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67ac98cc6dde43c90890a578
|
10.26434/chemrxiv-2025-xqprl
|
Improving Pitting Corrosion Prediction Accuracy in 316L Stainless Steel through the Synergy of Predictive Machine Learning and Reflective Microscopy
|
Accurately forecasting the locations of future pit formation sites on stainless steels (SS) holds significant practical value in both fundamental science and the corrosion industry, yet it poses a significant experimental challenge due to the need to localize imperfections in the passive film at a sub-nanometer scale. In this study, we tackle this issue by utilizing the combination of in-situ Reflective Microscopy (RM) instrumentation, optical modeling, and predictive machine learning (ML) methods, focusing on the prediction of pits location in SS316L alloy in chloride-rich media. Our findings indicate that the appearance of future pits is most often linked to slight ( 0.5%) decrease in the intensity of light reflected from the SS surface, yet this relationship is not always reciprocal. Optical modeling reinforced with ex-situ XPS suggest a chromium oxide deficiency in the surface films over these zones. This study provides proof of concept that RM enforced with ML approaches can be used as an accessible, highly precise tool to define zones of preferential pitting corrosion and highlights future promising directions for developing predictive corrosion monitoring systems.
|
Aleksei Makogon; Leonardo Bertolucci Coelho; Jon Ustarroz; Frédéric Kanoufi; Slava SHKIRSKIY
|
Physical Chemistry; Nanoscience; Electrochemistry - Mechanisms, Theory & Study; Interfaces; Surface
|
CC BY 4.0
|
CHEMRXIV
|
2025-02-14
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/67ac98cc6dde43c90890a578/original/improving-pitting-corrosion-prediction-accuracy-in-316l-stainless-steel-through-the-synergy-of-predictive-machine-learning-and-reflective-microscopy.pdf
|
60c753e8337d6c0e34e28929
|
10.26434/chemrxiv.13562798.v1
|
A Universal Standard Archive File for Adsorption Data
|
<div>New advanced adsorbents are a crucial driver for the development of energy and environmental applications. Tremendous potential is provided by machine learning and data mining techniques, as these approaches can identify the most appropriate adsorbent for a particular application. However, the current scientific reporting of adsorption isotherms in graphs and figures is not adequate to reproduce original experimentally measured data.</div><div><br /></div><div>This report proposes the specification of a new standard adsorption information file (AIF) inspired by the ubiquitous crystallographic information file (CIF) and based on the self-defining text archive and retrieval (STAR) procedure, also used to represent biological nuclear magnetic resonance experiments (NMR-STAR). The AIF is a flexible and easily extended free-format archive file that is readily human and machine readable</div><div>and is simple to edit using a basic text editor or parse for database curation. This format represents the first steps toward an open adsorption data format as a basis for a decentralized adsorption data library.</div><div><br /></div><div>An open format facilitates the electronic transmission of adsorption data between laboratories, journals and larger databases, which is key in the effort to increase open science in the field of porous materials in the future.</div>
|
Jack D. Evans; Volodymyr Bon; Irena Senkovska; Stefan Kaskel
|
Hydrogen Storage Materials; Nanostructured Materials - Materials; Nanocatalysis - Catalysts & Materials; Thermodynamics (Chem. Eng.); Materials Chemistry
|
CC BY 4.0
|
CHEMRXIV
|
2021-01-18
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c753e8337d6c0e34e28929/original/a-universal-standard-archive-file-for-adsorption-data.pdf
|
65cad4d79138d23161fad45d
|
10.26434/chemrxiv-2024-7hkz8
|
Optimized Trifluoromethylation and OH Radical Labeling with Radiolysis Provide Two Fold Enhancement in the Resolution of Hydroxyl Radical Protein Footprinting
|
Hydroxyl radical based protein footprinting (HRPF) coupled with mass spectrometry is a valuable medium-resolution technique in structural biology, facilitating the assessment of protein structure and molecular-level interactions in a wide range of solution conditions. In hydroxyl radical protein footprinting with X-rays (XFP), hydroxyl radicals (•OH) generated by water radiolysis covalently label multiple amino acid (AA) side chains simultaneously. However, HRPF technologies faces challenges in achieving their full potential due to the broad (>103) dynamic range of AA’s reactivity to •OH and the difficulty to detect slightly modified residues, particularly in peptides with highly reactive residues like methionine-containing peptides and in peptides containing all low reactive residues. To overcome this limitation, we developed a synchrotron-based multiplex labeling chemistry that utilizes CF3 radicals (•CF3) produced from a trifluoromethylation (TFM) reagent under controlled and optimized •OH doses generated by X-rays. We optimized the dual •CF3/•OH chemistry in this TFM labeling approach using six model peptides and lysozyme, there-by extending the existing •OH labeling platform with simultaneous •CF3 labeling. This optimization led to a two-fold increase in labeled AAs in multiplex TFM labeling, primarily by labeling to a greater degree AAs with low •OH reactivity via the •CF3 channel, while moderate and highly •OH reactive AAs were labeled in both •CF3 and •OH channels. Importantly, the low reactivity of methionine to •CF3 enabled the detection and quantification of additional AAs labeled by •CF3 across methionine-containing pep-tides. Consistent with observations in model peptides and protein, we observed a balanced dual •CF3/•OH chemistry and more uniform labeling of residues in both •CF3/•OH channels optimizing protein footprinting. Furthermore, the solvent accessibility of lysozyme residues directly correlated with •CF3 labeling demonstrating that multiplex labeling enables a high-resolution assessment of molecular interactions for enhanced HRPF.
|
Rohit Jain; Erik R. Farquhar; Nanak S. Dhillon; Nayeon Jeon; Mark R. Chance; Janna Kiselar
|
Analytical Chemistry; Mass Spectrometry; Spectroscopy (Anal. Chem.)
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2024-02-14
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/65cad4d79138d23161fad45d/original/optimized-trifluoromethylation-and-oh-radical-labeling-with-radiolysis-provide-two-fold-enhancement-in-the-resolution-of-hydroxyl-radical-protein-footprinting.pdf
|
66df910912ff75c3a1e6a92c
|
10.26434/chemrxiv-2024-v4c39-v2
|
Organo-electrocatalyst realizing efficient hydrogen production
|
Hydrogen is not only a green fuel but also a source of life at the beginning of the universe. Till now, electro-catalyzed hydrogen production plays an essential role in high-purity hydrogen production, where platinum-based catalysts take up the main parts due to their high efficiency and durability. However, the limited resources and high costs of noble metal species prohibit its larger-scale application, making it necessary to put forward new alternatives. The organocatalysts thus show promising potential in the practical industry, which is easy to design and synthesize. More importantly, it doesn’t contain any metal, cutting down the costs. In this work, the organocatalysts containing nitrogen and phosphorus sites are designed, exhibiting high catalytic activity (19 mV@10 mA·cm-2, 143 mV@400 mA·cm-2) and stability (more than 60 days) in hydrogen evolution reaction (HER). With organocatalysts firstly applied in practical hydrogen production, the price of H2 per Nm3 (0.37 $ꞏNm-3) is reduced to half of the Pt-based catalysts, making it possible for society to step into the green-H2 era. Moreover, since organocatalysts are introduced into inorganic electrochemistry, a field of organ-electrocatalysis will arise, bringing evolution in metal-dominated cathodic electrocatalysis and traditional organic catalysis as well.
|
Jiarui Yang; Wen-hao Li; Dingsheng Wang; Yadong Li
|
Organic Chemistry; Inorganic Chemistry; Catalysis; Physical Organic Chemistry; Electrocatalysis; Organocatalysis
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2024-09-10
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/66df910912ff75c3a1e6a92c/original/organo-electrocatalyst-realizing-efficient-hydrogen-production.pdf
|
60c74a94567dfe27b8ec4dcb
|
10.26434/chemrxiv.12218294.v1
|
TorchANI: A Free and Open Source PyTorch Based Deep Learning Implementation of the ANI Neural Network Potentials
|
<div>This paper presents TorchANI, a PyTorch based software for training/inference</div><div>of ANI (ANAKIN-ME) deep learning models to obtain potential energy surfaces and</div><div>other physical properties of molecular systems. ANI is an accurate neural network</div><div>potential originally implemented using C++/CUDA in a program called NeuroChem.</div><div>Compared with NeuroChem, TorchANI has a design emphasis on being light weight,</div><div>user friendly, cross platform, and easy to read and modify for fast prototyping, while</div><div>allowing acceptable sacrifice on running performance. Because the computation of</div><div>atomic environmental vectors (AEVs) and atomic neural networks are all implemented</div><div>using PyTorch operators, TorchANI is able to use PyTorch’s autograd engine to automatically compute analytical forces and Hessian matrices, as well as do force training</div><div>without additional codes required.</div>
|
Xiang Gao; Farhad Ramezanghorbani; Olexandr Isayev; Justin Smith; Adrian Roitberg
|
Computational Chemistry and Modeling; Theory - Computational; Machine Learning; Artificial Intelligence
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2020-05-04
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74a94567dfe27b8ec4dcb/original/torch-ani-a-free-and-open-source-py-torch-based-deep-learning-implementation-of-the-ani-neural-network-potentials.pdf
|
64de10f701042bc1cc3348a3
|
10.26434/chemrxiv-2023-v4824-v2
|
In situ Observation of Nanoparticle Photocharging: Gold Nanorods as Photochemical Capacitors
|
Light can photochemically charge plasmonic nanoparticles and in doing so modulate their Fermi level. Although this effect is increasingly applied to rationalize the kinetic enhancement observed in plasmonic photochemistry, the underlying charging mechanism is challenging to trace experimentally. Here, we introduce a method to observe the charging process of gold nanorods \textit{in situ} by tracing the longitudinal plasmon resonance during the photoinduced charge transfer from a hole scavenger. The obtained data provides spectroscopic evidence that the charging process can be understood in the frame of a nanoscale capacitor model, were the applied voltage is governed by the chemical potential of holes generated in the 5d-bands of gold. We also investigated the influence of particle size, oxygen content in the solvent and ligand on the charging, which further corroborates the proposed capacitor model. This work presents the first step for the rational engineering of Fermi levels in plasmon photochemistry.
|
Felix Stete; Wouter Koopman; Matias Bargheer
|
Physical Chemistry; Materials Science; Nanoscience; Plasmonic and Photonic Structures and Devices; Photochemistry (Physical Chem.); Spectroscopy (Physical Chem.)
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2023-08-17
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/64de10f701042bc1cc3348a3/original/in-situ-observation-of-nanoparticle-photocharging-gold-nanorods-as-photochemical-capacitors.pdf
|
60c742294c89194403ad23ea
|
10.26434/chemrxiv.8208656.v1
|
Iridium-Catalyzed Enantioselective Allylic Substitution with Aqueous Solutions of Nucleophiles
|
The iridium-catalyzed asymmetric allylic substitution
under biphasic conditions is reported. This approach allows the use of various
unstable and/or volatile nucleophiles including hydrazines, methylamine, <i>t</i>-butyl hydroperoxide, <i>N</i>-hydroxylamine, α-chloroacetaldehyde
and glutaraldehyde. This transformation provides rapid access to a broad range
of products from simple starting materials in good yields and up to >99% ee
and 20:1 d.r.. Additionally, these products can be elaborated efficiently into
a diverse set of cyclic and acyclic compounds, bearing up to four stereocenters
|
Tobias Sandmeier; Friedrich Wieland Goetzke; Simon Krautwald; Erick Carreira
|
Organic Synthesis and Reactions; Stereochemistry; Catalysis
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2019-06-04
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c742294c89194403ad23ea/original/iridium-catalyzed-enantioselective-allylic-substitution-with-aqueous-solutions-of-nucleophiles.pdf
|
60c753bcf96a0013d82884f0
|
10.26434/chemrxiv.13520156.v1
|
Synthesis and Characterization of Stearic Acid-Beclomethasone Dipropionate Conjugates with the Potential for Improving Loading Capacity in Lipid-based Nanoparticles
|
<p>Lipid-based nanoparticles (LBNs) are a new type of nanoparticulate drug delivery system, which have been gradually shown broad prospects in pulmonary drug delivery systems. However, the main disadvantage of these LBNs for inhalable drugs with limited lipophilicity is the low encapsulation capacity. Herein, this study anticipates establishing a technology platform to improve the loading capacity of low lipophilicity drugs in LBNs, for the therapy of lung diseases. A proof-of-concept was carried out using Beclomethasone dipropionate (BDP) as a model drug. BDP was conjugated with stearic acid (SA), a kind of the lipid matrix for LBN. The conjugate was characterized and the interactions between the conjugate and SA were investigated by molecular dynamics simulation. It is expected that the drug loading capacity of weak-lipophilic drugs in LBN can be increased by establishing the technology platform, and the application of LBNs in pulmonary delivery can be broadened.</p>
|
Shishuai Dang; Zhengwei Huang; Ying Huang; Xin Pan; Chuanbin Wu
|
Drug Discovery and Drug Delivery Systems
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2021-01-11
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c753bcf96a0013d82884f0/original/synthesis-and-characterization-of-stearic-acid-beclomethasone-dipropionate-conjugates-with-the-potential-for-improving-loading-capacity-in-lipid-based-nanoparticles.pdf
|
67d287e381d2151a02341aa9
|
10.26434/chemrxiv-2025-45f9c
|
Synthesis of 2-Acetylnoviosamine by Hydrogenolytic Cleavage of a Spirocyclopropane
|
Preparation of a 2-acetamido derivative of the rare 5,5-gem-dimethyl-deoxy carbohydrate noviose is reported in this study. The synthesis starts from readily available N-acetyl-ᴅ- mannosamine and tackles the introduction of the gem-dimethyl structural feature via a cyclopropanation and hydrogenolytic cleavage strategy, which can enable the synthesis of 2- amino noviose derivatives of both, L- and D-noviose.
|
Maruan D. Salim; Isabella Ferrara; Olivier Blacque; Karl Gademann
|
Organic Chemistry; Bioorganic Chemistry; Natural Products; Organic Synthesis and Reactions
|
CC BY 4.0
|
CHEMRXIV
|
2025-03-14
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/67d287e381d2151a02341aa9/original/synthesis-of-2-acetylnoviosamine-by-hydrogenolytic-cleavage-of-a-spirocyclopropane.pdf
|
649e529b9ea64cc167336cea
|
10.26434/chemrxiv-2023-4bmp3
|
Dearomative, aminocatalytic normal-electron-demand aza-Diels-Alder cycloaddition in the synthesis of tetrahydrofuropyridines
|
In the manuscript the application of dearomative normal-electron-demand aza-Diels-Alder cycloaddition in the synthesis of tetrahydrofuropyridines is described. The developed approach utilizes aminocatalytic activation of 2-alkyl-3-furfurals that proceeds via formation of dearomatized dienamine intermediate. Initially obtained cycloadducts have been subjected to subsequent transformations providing access to tetrahydrofuropyridines or functionalized cinnamates indicating the potential of the developed methodology. The mechanism of the process has been confirmed by DFT calculations.
|
Mateusz Dyguda; Artur Przydacz; Łukasz Albrecht
|
Organic Chemistry; Catalysis; Stereochemistry; Organocatalysis
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2023-06-30
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/649e529b9ea64cc167336cea/original/dearomative-aminocatalytic-normal-electron-demand-aza-diels-alder-cycloaddition-in-the-synthesis-of-tetrahydrofuropyridines.pdf
|
60c73ec39abda23cb1f8b931
|
10.26434/chemrxiv.7092833.v1
|
Formal Synthesis of Actinoranone Using a Racemization-Free One-Pot Semipinacol Rearrangement/Wittig Reaction
|
Here, we report a formal synthesis of the marine cytotoxic meroterpenoid actinoranone. Key steps include a racemization-free semipinacol rearrangement/Wittig reaction sequence and a chiral pool approach for the syntheses of the tetralone and the decalin fragments, respectively. The presented route provides access to the natural product in 14 steps in the longest linear sequence.
|
Martina Menger; Mathias Christmann
|
Natural Products; Organic Synthesis and Reactions; Chemical Biology; Drug Discovery and Drug Delivery Systems
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2018-09-18
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c73ec39abda23cb1f8b931/original/formal-synthesis-of-actinoranone-using-a-racemization-free-one-pot-semipinacol-rearrangement-wittig-reaction.pdf
|
618591aa7a002128ad47defb
|
10.26434/chemrxiv-2021-wktnm
|
Impacts of FERC Order No. 2222 on Dairy Manure Processing in Wisconsin
|
The agricultural practice of spreading dairy manure to fertilize crop fields leads to widespread air and water pollution, due to uncontrolled release of greenhouse gases, nutrients, and pathogens. The associated environmental and health impacts can be mitigated by deploying manure processing (MP) systems that can capture methane to produce electricity and that facilitate nutrient management. Unfortunately, electricity rates available to MP systems in the United States (US) provide limited economic incentives to promote their deployment. Recent policy enacted by the Federal Energy Regulatory Commission (Order 2222) enables distributed energy resource (DER) systems (such as MP systems) to participate in wholesale electricity markets. We present supply chain and market analyses in Wisconsin showing that this order can help activate an electricity bioeconomy that can help mitigating environmental and health impacts resulting from manure spreading. We estimate that this bioeconomy could generate up to $131 million in revenue for dairy farms annually while averting $39 million in greenhouse gas emissions and $182 million in nutrient emissions.
|
Evan Erickson; Philip Tominac; Victor Zavala
|
Energy; Chemical Engineering and Industrial Chemistry; Agriculture and Food Chemistry; Natural Resource Recovery; Power
|
CC BY 4.0
|
CHEMRXIV
|
2021-11-08
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/618591aa7a002128ad47defb/original/impacts-of-ferc-order-no-2222-on-dairy-manure-processing-in-wisconsin.pdf
|
60f0b82b7e67973c2b4efb5e
|
10.26434/chemrxiv-2021-h06nc-v2
|
Divergent Stereochemical Outcomes in the Insertion of Donor/Donor Carbenes into the C–H Bonds of Stereogenic Centers
|
Intramolecular C–H insertions with donor/donor dirhodium carbenes provide a concise and highly stereoselective method to set two contiguous stereocenters in a single step. Herein, we report the insertion of donor/donor carbenes into stereogenic carbon centers allowing access to trisubstituted benzodihydrofurans in a single step. This study illuminates, for the first time, the stereochemical impact on the carbene center and delineates the structural factors that enable control over both stereogenic centers. Sterically bulky, highly activated C–H insertion centers exhibit high substrate control yielding a single diastereomer and a single enantiomer of product regardless of the catalyst used. Less bulky, less activated C–H insertion centers exhibit catalyst control over the diastereomeric ratio (dr) wherein a single enantiomer of each diastereomer is observed. A combination of experimental studies and DFT calculations elucidates the origin of these results. First, hydride transfer from the stereogenic insertion site proceeds with high stereoselectivity to the carbene center, thus determining the absolute configuration of the product. Second, the short lived zwitterionic intermediate can undergo diastereoselective ring-closure by an SE2 mechanism that is either controlled by the substrate or the catalyst. These results demonstrate that donor/donor carbenes exhibit uniquely stereoselective reactions that originate from a stepwise reaction mechanism, in contrast to the analogous concerted reactions of carbenes with one or more electron-withdrawing groups attached.
|
Sarah Dishman; Croix Laconsay; James Fettinger; Dean Tantillo; Jared Shaw
|
Organic Chemistry; Stereochemistry
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2021-07-16
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60f0b82b7e67973c2b4efb5e/original/divergent-stereochemical-outcomes-in-the-insertion-of-donor-donor-carbenes-into-the-c-h-bonds-of-stereogenic-centers.pdf
|
60c743f9ee301c35ebc790bb
|
10.26434/chemrxiv.9730694.v1
|
Efficient Co-Harvesting of Solar Energy and Low-Grade Heat by Molecular Photoswitches for High Energy Density, Long-Term Stable Solar Thermal Battery
|
Solar
energy and ambient heat are two inexhaustible energy sources for addressing the
global challenge of energy and sustainability. Solar thermal battery based on molecular
switches that can store solar energy and release it as heat has recently attracted
great interest, but its development is severely limited by both low energy
density and short storage stability. On the other hand, the efficient recovery
and upgrading of low-grade heat, especially that of the ambient heat, has been
a great challenge. Here we report that solar energy and ambient heat can be
simultaneously harvested and stored, which is enabled by room-temperature
photochemical crystal-to-liquid transitions of small-molecule photoswitches.
The two forms of energy are released together to produce high-temperature heat during
the reverse photochemical phase change. This strategy, combined with molecular
design, provides high energy density of 320-370 J/g and long-term storage
stability (half-life of about 3 months). On this basis, we fabricate
high-performance, flexible film devices of solar thermal battery, which can be
readily recharged at room temperature with good cycling ability, show fast rate
of heat release, and produce high-temperature heat that is >20<sup> o</sup>C
higher than the ambient temperature. Our work opens up a new avenue to harvest ambient
heat, and demonstrate a feasible strategy to develop high-performance solar
thermal battery.
|
Zhao-Yang Zhang; Tao LI
|
Fuel Cells
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2019-08-27
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c743f9ee301c35ebc790bb/original/efficient-co-harvesting-of-solar-energy-and-low-grade-heat-by-molecular-photoswitches-for-high-energy-density-long-term-stable-solar-thermal-battery.pdf
|
628291f159f0d66afe92a41a
|
10.26434/chemrxiv-2022-8j6wb
|
A compact photoreactor for automated H2 photoproduction: revisiting the (Pd, Pt, Au)/TiO2 (P25) Schottky junctions
|
The configuration and geometry of chemical reactors underpins the accuracy of performance evaluation for photocatalytic materials and, accordingly, the development and validation of thermodynamic and kinetic model reactions. The lack of accurate photonic, mass, and heat transport profiles for photochemical reactors hinder standardization, scale-up, and ultimately comparison between different experiments. This work proposes two contributions at the interface between engineering of chemical process and materials science: (A) an automated compact stainless-steel photoreactor with 40 cm3 and 65 cm2 of volume and area, respectively, for hydrogen photoproduction as a model reaction and (B) the synthesis, characterization, and performance of TiO2 Schottky junctions, using Pd, Pt, or Au nanoparticles (ca. 0.5, 1, 2wt.% loadings each) to validate the operation of the reactor. A photonic profile methodology is implemented to the studied reactor to obtain the local light absorption profile, opening up for evaluation of the local quantum yield calculation for the selected materials. A combination of transmission electron microscopy, (X-ray/ultraviolet) photoelectron/electron, energy loss/infrared spectroscopies, X-ray scattering, inductively coupled plasma atomic emission spectroscopy, and ultraviolet-visible spectrophotometry is employed to determine the distinctive surface and bulk properties to build structure-function correlations. The (Pd, Pt, Au)/TiO2 Schottky junction exhibits H2 production rates slightly higher than previous studies, with quantum yields almost 2-fold higher than reported values. These results, demonstrate that the proposed novel geometry of the photoreactor improves the photonic, heat, and mass profiles. An in-depth analysis of the Au plasmon was investigated coupling electron energy loss spectroscopy, UV-vis, and transmission electron microscope, resulting in insightful information about the Au NP mode at the TiO2 interface.
|
Pablo Jiménez-Calvo; Mario J. Muñoz-Batista; Mark Isaacs; Xiaoyan Li; Miguel Ángel Muñoz-Márquez; Gilberto Teobaldi; Mathieu Kociak; Erwan Paineau
|
Chemical Engineering and Industrial Chemistry; Reaction Engineering; Materials Chemistry
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2022-05-20
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/628291f159f0d66afe92a41a/original/a-compact-photoreactor-for-automated-h2-photoproduction-revisiting-the-pd-pt-au-ti-o2-p25-schottky-junctions.pdf
|
66e6be8ccec5d6c14220bd8f
|
10.26434/chemrxiv-2024-9x1jz
|
q-BWF functions to deconvolute the attenuated total reflectance infrared spectra of the barite-group minerals
|
Here we consider the minerals in the barite group and their attenuated total reflectance (ATR) infrared spectra, that we can find in the RRUFF database. We apply the q-BWF functions to deconvolute the components of the spectra. The q-BWF functions are the asymmetric line shapes that Sparavigna defined in 2023, to generalize the BWF (Breit-Wigner-Fano) functions. Good results are obtained for the deconvolution of barite, celestine and anhydrite ATR-IR spectra.
|
Amelia Carolina Sparavigna
|
Materials Science
|
CC BY 4.0
|
CHEMRXIV
|
2024-09-17
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/66e6be8ccec5d6c14220bd8f/original/q-bwf-functions-to-deconvolute-the-attenuated-total-reflectance-infrared-spectra-of-the-barite-group-minerals.pdf
|
64970d6a4821a835f355c8b9
|
10.26434/chemrxiv-2023-jfzrf-v2
|
Multi-fidelity Bayesian Optimization of Covalent Organic Frameworks for Xenon/Krypton Separations
|
Our objective is to search a large candidate set of covalent organic frameworks (COFs) for the one with the largest equilibrium adsorptive selectivity for xenon (Xe) over krypton (Kr) at room temperature. To predict the Xe/Kr selectivity of a COF structure, we have access to two molecular simulation techniques: (1) a higher-fidelity, binary grand canonical Monte Carlo simulation and (2) a lower-fidelity Henry coefficient calculation that (a) approximates the adsorbed phase as dilute and, consequently, (b) incurs a smaller computational runtime than the higher-fidelity simulation.
To efficiently search for the COF with the largest high-fidelity Xe/Kr selectivity, we employ a multi-fidelity Bayesian optimization (MFBO) approach. MFBO constitutes a sequential, automated feedback loop of (1) conduct a low- or high-fidelity molecular simulation of Xe/Kr adsorption in a COF, (2) use the simulation data gathered thus far to train a surrogate model that cheaply predicts, with quantified uncertainty, the low- and high-fidelity simulated Xe/Kr selectivity of COFs from their structural/chemical features, and then (3) plan the next simulation (i.e., choose the next COF and fidelity) in consideration of balancing exploration, exploitation, and cost.
We find that MFBO acquires the optimal COF among the candidate set of 609 structures using only 38 low-fidelity and nine high-fidelity simulations, incurring only 2.5%, 5% on average, and 18% on average of the computational runtime of an exhaustive, random, and single-fidelity BO search, respectively.
|
Nickolas Gantzler; Aryan Deshwal; Janardhan Rao Doppa; Cory Simon
|
Theoretical and Computational Chemistry; Materials Science; Nanostructured Materials - Materials; Theory - Computational; Artificial Intelligence
|
CC BY 4.0
|
CHEMRXIV
|
2023-06-26
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/64970d6a4821a835f355c8b9/original/multi-fidelity-bayesian-optimization-of-covalent-organic-frameworks-for-xenon-krypton-separations.pdf
|
6438a24e1d262d40ea69b61c
|
10.26434/chemrxiv-2023-l3sjk
|
2,3-Diarylmaleate salts as a versatile class of diarylethenes with a full spectrum of photoactivity in water
|
There is an incessant interest in transfer of common chemical processes from organic solvents to water, which is vital for the development of bioinspired and green chemical technologies. Diarylethenes feature a rich photochemistry, including both irreversible and reversible reactions that are in demand in organic synthesis, materials chemistry, and photopharmacology. Herein, we introduce the first versatile class of diarylethenes, namely, potassium 2,3-diarylmaleates (DAMs), that show excellent solubility in water. DAMs obtained from highly available precursors feature a full spectrum of photoactivity in water and undergo irreversible reactions (oxidative cyclization to phenanthrenes or rearrangement) or reversible photocyclization (switching), depending on their structure. This finding paves a way towards wider application of DAEs in photopharmacology and bioinspired technologies that require aqueous media for photochemical reactions.
|
Iumzhana Bolotova; Alexander Ustyuzhanin; Ekaterina Sergeeva; Anna Faizdrakhmanova; Yu Hai ; Andrey Stepanov; Igor Ushakov; Konstantin Lyssenko; Lei You; Andrey Lvov
|
Organic Chemistry; Materials Science; Organic Compounds and Functional Groups; Photochemistry (Org.); Dyes and Chromophores
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2023-04-17
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6438a24e1d262d40ea69b61c/original/2-3-diarylmaleate-salts-as-a-versatile-class-of-diarylethenes-with-a-full-spectrum-of-photoactivity-in-water.pdf
|
624ffff36574b21550c4cf0f
|
10.26434/chemrxiv-2022-jhn28
|
Structural Diversity in Oxoiridates with 1D IrnO3(n+1) Chain Fragments and Flat Bands
|
A previously unreported series of hexagonal-perovskite-based Rb-oxoiridates, Rb5Ir2O9, Rb7Ir3O12, and Rb12Ir7O24, have been synthesized and structurally analyzed via N2-protected single-crystal X-ray diffraction (SC-XRD). These materials exhibit different 1D IrnO3(n+1) chain fragments along their c axes. IrO6 Octahedra and RbOx (x = 6, 8, and 10) polyhedra are their basic building blocks. The IrO6 octahedra are linked via face-sharing, forming Ir2O9 dimers, Ir3O12 trimers, and Ir7O24 heptamers. The nonmagnetic RbOx (x = 6, 8, and 10) polyhedra serve as both bridging units and spacers. Temperature-dependent SC-XRD shows all three to display positive thermal expansion and rules out structural transitions from their triangular symmetries down to 100 K. Density functional theory results suggest semiconducting-like behavior for the title compounds. The flatness of the electronic bands and our structural analysis are of potential interest for understanding and designing 1D quantum materials.
|
Shu Guo; Hillary E. Mitchell Warden; R. J. Cava
|
Materials Science; Inorganic Chemistry; Magnetic Materials; Transition Metal Complexes (Inorg.); Materials Chemistry
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2022-04-12
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/624ffff36574b21550c4cf0f/original/structural-diversity-in-oxoiridates-with-1d-irn-o3-n-1-chain-fragments-and-flat-bands.pdf
|
64cf779f4a3f7d0c0db36ba4
|
10.26434/chemrxiv-2023-gvqnl
|
The Kinetic Stereocontrol in Brøsted Acid-catalyzed Pictet-Spengler Reaction and the Dynamic Epimerization Mechanism via Crystallization-induced Diastereomer Transformations
|
The merging of asymmetric catalysis with crystallization-induced diastereomer transformations (CIDTs) shows promise as a practical method for the synthesis of chiral molecules with one or more epimerization carbons. A successful sample is the merging of acid-catalyzed asymmetric Pictet-Spengler reaction with CIDTs for the efficient construction of chiral complex bioactive indole alkaloids like tetrahydrocarbolines. But the rule of the kinetic control is not yet fully understood. Meanwhile the structure factor on controlling the thermodynamic diastereoselectivity (beyond the solubility factor) in epimerization of 1,3-disubstituted-tetrahydro-β-carbolines via CIDTs in organic solvent/water is also unknown. For advanced understanding of the stereocontrol, the dominant non-covalent interactions would be identified based on a hydrated imine cation model. The potential of both systems as a small molecular model for future quantitative study of biologically relevant non-covalent interactions would also be discussed.
|
Liuqun Gu
|
Biological and Medicinal Chemistry; Organic Chemistry; Catalysis; Chemical Biology; Drug Discovery and Drug Delivery Systems; Acid Catalysis
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2023-08-08
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/64cf779f4a3f7d0c0db36ba4/original/the-kinetic-stereocontrol-in-br-sted-acid-catalyzed-pictet-spengler-reaction-and-the-dynamic-epimerization-mechanism-via-crystallization-induced-diastereomer-transformations.pdf
|
60c758660f50dbf37b398433
|
10.26434/chemrxiv.14547342.v1
|
Scalable 18F Processing Conditions for Copper-Mediated Radiofluorination Chemistry Facilitate "Design of Experiments" (DoE) Optimization Studies and Afford an Improved Synthesis of [18F]Olaparib.
|
A convenient, scalable, and azeotropic drying free method for processing [18F]fluoride as base free<br />[18F]TBAF is reported and applied to copper-mediated radiofluorination (CMRF) radiosyntheses. A central<br />feature of this method is that a single production of [18F]TBAF can be divided into small aliquots that can be<br />used to perform multiple small-scale reactions in DoE optimization studies. The results of these studies can<br />then be reliably translated to full batch tracer productions using automated synthesizers. This processing<br />technique was successfully applied to the manual DoE optimization, DoE study validation, and subsequent<br />full-batch automation of the PARP-1 tracer [18F]olaparib. After DoE optimization, we were able to produce<br />[18F]olaparib in high radiochemical yields via both manual (%RCY (CMRF step only) = 78 ± 6 %, n = 4) and<br />automated (up to 80% radiochemical yield (%RCY); 41% activity yield (%AY)) radiosynthesis procedures.<br />This work further demonstrates the power of the DoE approach for improving the radiochemical yields and<br />radiosynthesis performance of clinically relevant tracer productions
|
Gregory D. Bowden; Nantanat Chailanggar; Bernd J. Pichler; Andreas Maurer
|
Organic Synthesis and Reactions; Imaging Agents; Nuclear Chemistry
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2021-05-07
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c758660f50dbf37b398433/original/scalable-18f-processing-conditions-for-copper-mediated-radiofluorination-chemistry-facilitate-design-of-experiments-do-e-optimization-studies-and-afford-an-improved-synthesis-of-18f-olaparib.pdf
|
6629401e418a5379b09d4c33
|
10.26434/chemrxiv-2024-605dd-v2
|
Borylation and rearrangement reactions of azasilaanthracenes to afford B,N-doped nanographenes
|
An air-stable B3,N3-containing dibenzobisanthene (8) was prepared in 29% yield by heating a 1,3,5-tri(azasilaanthryl)benzene (5) with BBr3 (180 °C). Under these conditions, the reaction does not stop after threefold SiMe2/BBr exchange but proceeds further via two rearrangement and two intramolecular C–H borylation steps. Some mechanistic details were unveiled by using smaller model systems and applying lower reaction temperatures. According to X-ray crystallography, compound 8 has a helically distorted scaffold. Due to its multiple resonance structure, it shows a narrow-band blue-green emission (λem = 493 nm; ΦPL = 84%; FWHM = 0.20 eV; THF); samples measured in PMMA gave prompt and delayed fluorescence lifetimes of 10.7 ns and 136 μs, respectively. The optical properties of 8 and of structurally related species were also investigated by quantum-chemical means: Most of these compounds exhibit a small energy gap ΔEST between the lowest excited singlet (S1) and triplet (T1) states and a non-negligible spin-orbit coupling (SOC) between S1 and T1/T2, demonstrating their potential as thermally activated delayed fluorescence (TADF) emitters
|
Elena Zender; Danillo Valverde; Robert Neubaur; Sebastian Karger; Alexander Virovets; Michael Bolte; Hans-Wolfram Lerner; Matthias Wagner; Yoann Olivier
|
Theoretical and Computational Chemistry; Organic Chemistry; Materials Chemistry
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2024-04-25
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6629401e418a5379b09d4c33/original/borylation-and-rearrangement-reactions-of-azasilaanthracenes-to-afford-b-n-doped-nanographenes.pdf
|
6606dc8566c138172934fdc4
|
10.26434/chemrxiv-2024-d20px-v2
|
Beyond Molecular Structure: Critically Assessing Machine Learning for Designing Organic Photovoltaic Materials and Devices
|
Our study explores the current state of machine learning (ML) as applied to predicting and designing organic photovoltaic (OPV) devices. We outline key considerations for selecting the method of encoding a molecular structure and selecting the algorithm while also emphasizing important aspects of training and rigorously evaluating ML models. This work presents the first dataset of OPV device fabrication data mined from the literature. The top models achieve state-of-the-art predictive performance. In particular, we identify an algorithm that is used less frequently, but may be particularly well suited to similar datasets. However, predictive performance remains modest (R2 ≅ 0.6) overall. An in-depth analysis of the dataset attributes this limitation to challenges relating to the size of the dataset, as well as data quality and sparsity. These aspects are directly tied to difficulties imposed by current reporting and publication practices. Advocating for standardized reporting of OPV device fabrication data reporting in publications emerges as crucial to streamline literature mining and foster ML adoption. This comprehensive investigation emphasizes the critical role of both data quantity and quality, and highlights the need for collective efforts to unlock ML's potential to drive advancements in OPV.
|
Martin Seifrid; Stanley Lo; Dylan G. Choi; Gary Tom; My Linh Le; Kunyu Li; Rahul Sankar; Hoai-Thanh Vuong; Hiba Wakidi; Ahra Yi; Ziyue Zhu; Nora Schopp; Aaron Peng; Benjamin Luginbuhl; Thuc-Quyen Nguyen; Alán Aspuru-Guzik
|
Theoretical and Computational Chemistry; Materials Science; Energy; Carbon-based Materials; Machine Learning; Photovoltaics
|
CC BY 4.0
|
CHEMRXIV
|
2024-04-01
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6606dc8566c138172934fdc4/original/beyond-molecular-structure-critically-assessing-machine-learning-for-designing-organic-photovoltaic-materials-and-devices.pdf
|
67165e8712ff75c3a1142bb7
|
10.26434/chemrxiv-2024-sgtgf-v2
|
Chemical proteomics reveal human off-targets of fluoroquinolone induced mitochondrial toxicity
|
Fluoroquinolones (FQs) are an important class of potent broad-spectrum antibiotics. However, their general use is more and more limited by adverse side effects. While general mechanisms for the fluoroquinolone-associated disability (FQAD) have been identified, the underlying molecular targets of toxicity remain elusive. In this study, focusing on the most commonly prescribed FQs Ciprofloxacin and Levofloxacin, whole proteome analyses revealed prominent mitochondrial dysfunction in human cells, specifically of the complexes I and IV of the electron transport chain (ETC). Furthermore, global untargeted chemo-proteomic methodologies such as photo-affinity profiling with FQ-derived probes, as well as derivatization-free thermal proteome profiling, were applied to elucidate human protein off-targets of FQs in living cells. Accordingly, the interactions of FQs with mitochondrial AIFM1 and IDH2 have been identified and biochemically validated for their contribution to mitochondrial dysfunction. Of note, the FQ induced ETC dysfunction via AIFM1 activates the reverse carboxylation pathway of IDH2, however, its simultaneous inhibition triggers mitochondrial toxicity. This off-target discovery study provides unique insights into FQ toxicity enabling the utilization of identified molecular principles for the design of a safer FQ generation.
|
Till Reinhardt; Nina C. Bach; Alex Rothemann; Adrian T. Jauch; Yassmine El Harraoui; Sigrid Müller-Deubert; Martin F. Köllen; Timo Risch; Lianne H.C. Jacobs; Rolf Müller; Franziska R. Traube; Denitsa Docheva; Stefan Zahler; Jan Riemer; Stephan A. Sieber
|
Biological and Medicinal Chemistry; Organic Chemistry; Bioorganic Chemistry; Biochemistry; Chemical Biology
|
CC BY 4.0
|
CHEMRXIV
|
2024-10-22
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/67165e8712ff75c3a1142bb7/original/chemical-proteomics-reveal-human-off-targets-of-fluoroquinolone-induced-mitochondrial-toxicity.pdf
|
60f1d64a78578710cc6a3e0a
|
10.26434/chemrxiv-2021-8lc01
|
Titanium carbide MXene shows an electrochemical anomaly in water-in-salt electrolytes
|
Identifying and understanding charge storage mechanisms is important for advancing energy storage, especially when new materials and electrolytes are explored. Well-separated peaks in cyclic voltammograms (CVs) are considered key indicators of diffusion-controlled electrochemical processes with distinct Faradic charge transfer. Herein, we report on an electrochemical system with separated CV peaks, accompanied by surface-controlled partial charge transfer, in 2D Ti3C2Tx MXene in water-in-salt electrolytes. The process involves the insertion/desertion of desolvation-free cations, leading to an abrupt change of the interlayer spacing between MXene sheets. This unusual behavior increases charge storage at positive potentials, thereby increasing the amount of energy stored. This also demonstrates new opportunities for the development of high-rate aqueous energy storage devices and electrochemical actuators using safe and inexpensive aqueous electrolytes.
|
Xuehang Wang; Tyler S. Mathis; Yangyunli Sun; Wan-Yu Tsai; Netanel Shpigel; Hui Shao; Danzhen Zhang; Kanit Hantanasirisakul; Fyodor Malchick; Nina Balke; De-en Jiang; Patrice Simon; Yury Gogotsi
|
Physical Chemistry; Electrochemistry - Mechanisms, Theory & Study; Materials Chemistry
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2021-07-19
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60f1d64a78578710cc6a3e0a/original/titanium-carbide-m-xene-shows-an-electrochemical-anomaly-in-water-in-salt-electrolytes.pdf
|
60c753a3bdbb89f645a3a4be
|
10.26434/chemrxiv.13521527.v1
|
Switching Between Enantiomers by Combining Chromoselective Photocatalysis and Biocatalysis
|
<a></a><a></a><a></a><a></a><a></a><a>Controlling the selectivity of a chemical
reaction with external stimuli is common in thermal processes, but rare in visible-light photocatalysis. Here we
show that the redox potential of a carbon nitride photocatalyst (CN-OA-m) can
be tuned by changing the irradiation wavelength to generate electron holes with
different oxidation potentials. This tuning was the key to realizing photo-chemo-enzymatic cascades that give either the (<i>S</i>)- or the (<i>R</i>)-enantiomer
of phenylethanol. In combination with an unspecific peroxygenase from <i>Agrocybe aegerita,</i> green light irradiation of CN-OA-m led to the
enantioselective hydroxylation of ethylbenzene to (<i>R</i>)-1-phenylethanol
(99% <i>ee</i>). In contrast, blue light irradiation triggered the
photocatalytic oxidation of ethylbenzene to acetophenone, which in turn was
enantioselectively reduced with an alcohol dehydrogenase from <i>Rhodococcus ruber </i>to form<i> </i>(<i>S</i>)-1-phenylethanol (93% <i>ee</i>).</a><a></a>
|
Luca Schmermund; Susanne Reischauer; Sarah Bierbaumer; Christoph Winkler; Alba Diaz-Rodriguez; Lee J. Edwards; Selin Kara; Tamara Mielke; Jared Cartwright; Gideon Grogan; Bartholomäus Pieber; Wolfgang Kroutil
|
Biocatalysis; Photocatalysis; Redox Catalysis
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2021-01-06
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c753a3bdbb89f645a3a4be/original/switching-between-enantiomers-by-combining-chromoselective-photocatalysis-and-biocatalysis.pdf
|
67857c8e6dde43c90865c472
|
10.26434/chemrxiv-2025-01g76
|
Rapid Multi-Omics for Bacteria Identifications using Flow Injection-Ion Mobility-Mass Spectrometry
|
Antibiotic resistance is one of the most serious public health concerns of our time. With limited development of new antimicrobials, attention has shifted towards ensuring that existing therapeutics maintain their efficacy against bacterial pathogens. In the case of bacterial infections, the ability to rapidly determine the organism and corresponding antibiotic susceptibility is vital to developing an effective treatment plan and preventing misuse of antibiotics. While there is currently no single, universal technology capable of obtaining both identifications and susceptibilities, the implementation of mass spectrometry in clinical microbiology has made significant improvement in the turnaround time from positive culture to identification. The current mass spectrometry approach exploits the unique protein fingerprints found across different genera of bacteria but struggles with identifications to the species level or lower because of the high degree of homology within a genus. However, other areas of development relying on the detection of bacterial lipids and small molecules with mass spectrometry have shown promise towards species-level identifications and detection of specific phenotypes, including those related to antibiotic resistance. While the concept of using multiple omics (or multi-omics) in diagnostic situations is not new, the issues of time and efficiency remain major hurdles to implementing multi-omic mass spectrometry into routine practice. To simultaneously obtain information provided by lipids and small molecules, we have developed a multi-omics strategy to bacterial identifications that relies on rapid gas separation separations by structure and mass using ion mobility-mass spectrometry (IM-MS). Proof of concept is demonstrated using strains of the leading causes of bacterial infections – the ESKAPE pathogens (Enterococci sp., Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter sp.). These results showcase the speed and capability of an IM-MS multi-omics workflow and show promise for expansion into more detailed identification methods in the future.
|
Hannah Hynds; Jana Carpenter; Kelly Hines
|
Analytical Chemistry; Biochemical Analysis; Mass Spectrometry
|
CC BY NC 4.0
|
CHEMRXIV
|
2025-01-17
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/67857c8e6dde43c90865c472/original/rapid-multi-omics-for-bacteria-identifications-using-flow-injection-ion-mobility-mass-spectrometry.pdf
|
661e90c121291e5d1df5b933
|
10.26434/chemrxiv-2024-9p76x
|
Mannose Presenting ‘Glyco-Colicins’ Convert the Bacterial Cell Surface into a Multivalent Adsorption Site for Adherent Bacteria
|
Biofilm formation is integral to the pathogenesis of numerous adherent bacteria and contributes to antimicrobial resistance (AMR). The rising threat of AMR means the need to develop novel non-bactericidal anti-adhesion approaches against such bacteria is more urgent than ever. Both adherent invasive Eschericia coli (AIEC, implicated in inflammatory bowel disease) and uropathogenic E. coli (UPEC, responsible for ~80% of urinary tract infections) adhere to terminal mannose sugars on epithelial glycoproteins through the FimH adhesin on their type 1 pilus. Although mannose-based inhibitors have previously been explored to inhibit binding of adherent bacteria to epithelial cells, this approach has been limited by monovalent carbohydrate-protein interactions. Herein we pioneer a novel approach to this problem through the preparation of colicin E9 bioconjugates that bind to the abundant BtuB receptor in the outer membrane of bacteria, enabling multivalent presentation of functional motifs on the cell surface. We show these bioconjugates label the surface of live E. coli, and furthermore demonstrate that mannose presenting “glyco-colicins” induce E. coli aggregation, using the bacteria itself as a multivalent platform for mannose display which triggers binding to adjacent FimH presenting bacteria.
|
Natasha Hatton; Joe Nabarro; Nicholas Yates; Alison Parkin; Laurence Wilson; Christoph Baumann; Martin Fascione
|
Biological and Medicinal Chemistry; Organic Chemistry; Chemical Biology
|
CC BY 4.0
|
CHEMRXIV
|
2024-04-17
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/661e90c121291e5d1df5b933/original/mannose-presenting-glyco-colicins-convert-the-bacterial-cell-surface-into-a-multivalent-adsorption-site-for-adherent-bacteria.pdf
|
60c74a65ee301c028ac79c40
|
10.26434/chemrxiv.12198039.v1
|
Newly Developed Semi-Synthetic Chloroquine and Hydroxychloroquine-Phytochemical Conjugates as Prospective COVID-19 Drug(s)
|
<p>Dear
Editor,</p>
<p> </p>
<p>Kindly
find a research article entitled “Newly developed semi-synthetic chloroquine
and hydroxychloroquine-phytochemical conjugates as prospective COVID-19 drug(s)”,
submitted<b> </b>for consideration for
publication. Kindly find the Herein, two series of chloroquine (CQ) and
hydroxychloroquine (HCQ) derivatives were chemically conjugated with
established small phenolic phytochemicals namely, thymol, vanillin, guaiacol,
eugenol, 4-hydroxycoumarin and vanillin analogues by the principles of
Williamson ether reaction. The HCQ-vanillin conjugation would be coveted as a
potential candidate against human COVID-19.</p>
<p><b> </b></p>
<p>Thanking
you,</p>
<p>With
regards,</p>
<p> </p>
<p>Rabindra
Nath Padhy, PhD, Post-Doc, Member NAMS.</p>
<p>Professor
and Head, Central Research Laboratory, IMS & Sum Hospital, </p>
<p>Siksha
‘O’ AnusandhanDeemed to be University, </p>
<p>Bhubaneswar-
751003, Odisha, India.</p>
<p>E-mail:
rnpadhy54@gmail.com</p><br />
|
Chita Ranjan Sahoo; Sudhir Kumar Paidesetty; Rabindra Padhy
|
Bioorganic Chemistry; Natural Products
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2020-04-27
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74a65ee301c028ac79c40/original/newly-developed-semi-synthetic-chloroquine-and-hydroxychloroquine-phytochemical-conjugates-as-prospective-covid-19-drug-s.pdf
|
63e504a01d2d1840632b4307
|
10.26434/chemrxiv-2023-l7rt1
|
Liquid Water : When Hyperpolarizability Fluctuations Boost and Reshape the Second Harmonic Scattering Intensities
|
Second Harmonic Scattering (SHS) is a method of choice to investigate the molecular structure of liquids. While a clear interpretation of SHS intensity exists for diluted solutions of dyes, the scattering due to solvents remains difficult to interpret quantitatively. Here, we report a quantum mechanics/molecular mechanics (QM/MM) approach to model the polarization-resolved SHS intensity of liquid water, quantifying different contributions to the signal. We point out that the molecular hyperpolarizability fluctuations and correlations cannot be neglected. The intermolecular orientational and hyperpolarizability correlations up to the third solvation layer strongly increase the scattering intensities, and modulate the polarization-resolved oscillation that is predicted here by QM/MM without fitting parameters. Our approach can be generalized to other pure liquids to provide a quantitative interpretation of SHS intensities in terms of short-range molecular ordering.
|
Guillaume Le Breton; Oriane Bonhomme; Emmanuel Benichou; Claire Loison
|
Theoretical and Computational Chemistry; Physical Chemistry
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2023-02-13
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/63e504a01d2d1840632b4307/original/liquid-water-when-hyperpolarizability-fluctuations-boost-and-reshape-the-second-harmonic-scattering-intensities.pdf
|
6341a223ea6a22bb990ecdc8
|
10.26434/chemrxiv-2022-w08rh
|
Online Protein Unfolding Characterized by Ion Mobility Electron Capture Dissociation Mass Spectrometry: Cytochrome C from Neutral and Acidic Solutions
|
Electrospray ionization mass spectrometry (ESI-MS) experiments, including ion mobility-mass spectrometry (ESI-IM-MS), and electron capture dissociation (ECD) of proteins ionized from aqueous solutions, have been used for the study of solution-like structures of intact proteins. By mixing aqueous proteins with denaturants online before ESI, the amount of protein unfolding can be precisely controlled and rapidly analyzed, permitting the characterization of protein folding intermediates in protein folding pathways. Herein, we mixed various pH solutions online with aqueous cytochrome C for unfolding and characterizing its unfolding intermediates with ESI-MS charge state distribution measurements, ion mobility, and ECD. The presence of folding intermediates and unfolded cytochrome c structures were detected from changes in charge states, arrival time distributions (ATDs), and ECD fragmentation. We also compared structures from nondenaturing and denaturing solution mixtures measured under “gentle” (i.e., low energy) ion transmission conditions with structures measured under “harsh” (higher energy) transmission. This work confirms that when using “gentle” instrument conditions, the gas-phase cytochrome c ions reflect attributes of the various solution-phase structures. However, “harsh” conditions that maximize ion transmission produce annealed, extended structures that no longer correlate with changes in solution structure.
|
Rebecca Cain; Ian Webb
|
Physical Chemistry; Biological and Medicinal Chemistry; Analytical Chemistry; Mass Spectrometry; Biochemistry; Structure
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2022-10-12
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6341a223ea6a22bb990ecdc8/original/online-protein-unfolding-characterized-by-ion-mobility-electron-capture-dissociation-mass-spectrometry-cytochrome-c-from-neutral-and-acidic-solutions.pdf
|
60c7530e4c89196fbaad424d
|
10.26434/chemrxiv.13383125.v1
|
Biomimetic Enterobactin Analogue Mediates Iron-Uptake and Cargo Transport into E. coli and P. aeruginosa
|
The design, synthesis
and biological evaluation of the artificial enterobactin analogue <b>Ent<sub>KL</sub></b>
and several fluorophore-conjugates thereof are described. <b>Ent<sub>KL</sub></b>
provides an attachment point for cargos such as fluorophores
or antimicrobial payloads. Corresponding conjugates are recognized by outer
membrane siderophore receptors of Gram-negative pathogens and retain the
natural hydrolyzability of the <i>tris</i>-lactone backbone, known to be key
for uptake into the cytosol. Initial density-functional theory (DFT)
calculations of the free energies of solvation (ΔG(sol)) and relaxed Fe-O force constants of the
corresponding <b>[Fe-Ent<sub>KL</sub>]<sup>3-</sup> </b>complexes<b> </b>indicated a similar iron binding
constant compared to natural enterobactin (<b>Ent</b>). The synthesis of <b>Ent<sub>KL</sub></b>
was achieved via an iterative assembly based on a 3-hydroxylysine building block over 14 steps with an overall yield of
3%. A series of growth recovery assays under iron-limiting conditions with <i>Escherichia coli</i>
and <i>Pseudomonas aeruginosa</i> mutant strains that are defective in natural
siderophore synthesis revealed a potent concentration-dependent growth
promoting effect of <b>Ent<sub>KL</sub></b> similar to natural <b>Ent</b>.
Additionally, four cargo-conjugates differing in molecular size were able to
restore growth of <i>E. coli</i> indicating an uptake into the cytosol. <i>P. aeruginosa
</i>displayed a stronger uptake promiscuity as six different cargo-conjugates
were found to restore growth under iron-limiting conditions. Imaging studies utilizing
BODIPY<sub>FL</sub>-conjugates, demonstrated the ability of <b>Ent<sub>KL</sub>
</b>to overcome the Gram-negative outer membrane permeability barrier and thus deliver
molecular cargos via the bacterial iron transport machinery of <i>E. coli</i>
and <i>P. aeruginosa</i>.
|
Robert Zscherp; Janetta Coetzee; Johannes Vornweg; Jörg Grunenberg; jennifer herrmann; rolf müller; Philipp Klahn
|
Chemical Biology; Drug Discovery and Drug Delivery Systems; Microbiology
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2020-12-17
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c7530e4c89196fbaad424d/original/biomimetic-enterobactin-analogue-mediates-iron-uptake-and-cargo-transport-into-e-coli-and-p-aeruginosa.pdf
|
645550f227fccdb3ea8cfd76
|
10.26434/chemrxiv-2023-m977f
|
In-situ monitoring of the material composition in PBF-LB via optical emission spectroscopy
|
Powder bed fusion using a laser beam of metals (PBF-LB/M) is a widely used additive manufacturing (AM) technique that enables the material-efficient fabrication of complex geometries in metallic parts. However, achieving high-quality parts with desired properties heavily depends on variances in the manufacturing process and powder composition, making quality control an indispensable aspect of almost all applications. Today, mainly grayscale imaging or pyrometry are employed, whereas in situ recording of chemical (compositional) information has rarely been done during LBF-LB/M. This pilot study explores the feasibility of in-situ optical emission spectroscopy (OES) for elemental analysis of metallic samples during PBF-LB, at the example of Nd-Fe-B. Our findings suggest that the local emissivity of Fe and Nd lines can serve as a reliable indicator to determine the temperature and elemental concentration in the plasma. The results showed that Online-OES during PBF-LB enables tracking of how Nd content in as-build parts critically depends on the laser parameter used while printing the part.
|
Anna Rosa Ziefuss; Rene Streubel; Philipp Gabriel; Florian Eibl; Stephan Barcikowski
|
Materials Science; Magnetic Materials; Materials Processing; Materials Chemistry
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2023-05-08
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/645550f227fccdb3ea8cfd76/original/in-situ-monitoring-of-the-material-composition-in-pbf-lb-via-optical-emission-spectroscopy.pdf
|
60c757a24c89191fc8ad4a5c
|
10.26434/chemrxiv.14439548.v1
|
Long-term Stabilized Amorphous Calcium Carbonate – an Ink for Bio-inspired 3D Printing
|
Amorphous
Calcium Carbonate (ACC) is a highly unstable amorphous precursor many organisms
utilize for the formation of crystals with intricate morphology and improved
mechanical properties. Herein, we report for the first-time high-yield long-term
stabilization of ACC, achieved via its co-precipitation in the presence of high
amounts of Mg and an acetone-based storage protocol. A novel use of the formed high-Mg
ACC paste as an ink for 3D printing techniques allows the formation of
bio-inspired intricately shaped calcium carbonate geometries. The obtained ink
can dry, though retains its amorphous nature, at a variety of temperatures
ranging from 25 to 150˚C
enabling various applications such as cultural heritage reconstruction and
artificial reefs formation. We also show the on-demand low-temperature
crystallization of the 3D printed ACC models, similar to what is achieved by
organisms in nature. Using this
bio-inspired crystallization route via transient amorphous precursor also enables
the presence of high Mg levels within the calcite crystalline lattice, far
beyond the thermodynamically stable solubility level. High levels of Mg incorporation,
in turns, encompasses a great promise for the enhancement in the mechanical
properties of the crystallized calcite 3D objects akin naturally found
crystalline CaCO<sub>3</sub>.
|
Hadar Shaked; Iryna Polishchuk; alina nagel; Yehonadav Bekenstein; Boaz Pokroy
|
Biological Materials
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2021-04-19
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c757a24c89191fc8ad4a5c/original/long-term-stabilized-amorphous-calcium-carbonate-an-ink-for-bio-inspired-3d-printing.pdf
|
62841594d55550f7eb9dd645
|
10.26434/chemrxiv-2022-sv6zf
|
Unravelling the synthesis of a rare-earth cluster-based metal–organic framework with spn topology
|
Y-CU-45, an analogue of Zr-MOF-808, is synthesized for the first time. Several reaction conditions are tested demonstrating that two fluorinated modulators are required for a reproducible synthesis yielding high quality material. Y-CU-45 shows high crystallinity and surface area, shining light on the potential for rare-earth cluster-based MOFs with open metal sites.
|
Hudson A. Bicalho; Felix Saraci; Jose de J. Velazquez-Garcia; Hatem M. Titi; Ashlee J. Howarth
|
Inorganic Chemistry; Coordination Chemistry (Inorg.); Materials Chemistry; Crystallography – Inorganic
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2022-05-19
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/62841594d55550f7eb9dd645/original/unravelling-the-synthesis-of-a-rare-earth-cluster-based-metal-organic-framework-with-spn-topology.pdf
|
634833324b0af32776c4102f
|
10.26434/chemrxiv-2022-1rc02-v2
|
Hydrophobized Poly(Heptazine Imide) for Highly Effective Photocatalytic Hydrogen Peroxide Production in a Biphasic Fatty Alcohol-Water System
|
Light-driven production of hydrogen peroxide via selective dioxygen reduction is an attractive “green” alternative to the conventionally used anthraquinone process. One of the most promising classes of photocatalytic materials for this conversion that excels by high selectivity, chemical stability and low cost is represented by polymeric carbon nitrides, and particularly by various types of poly(heptazine imide) (PHI), i.e., ionic variants of carbon nitride. A crucial challenge highlighted by recent studies is the problem of separation of formed H2O2 from the reaction medium and especially from the suspended photocatalyst particles since photocatalytically generated H2O2 can undergo light-driven decomposition, as well as disproportionation on the surface of the photocatalyst in the dark. Herein, we report an elegant solution to this problem by implementing a biphasic reaction system in which the hydrophobic photocatalyst oxidizes a lipophilic electron donor in the organic phase, while the produced H2O2 is instantaneously extracted into the aqueous layer. To this end, we have achieved an effective hydrophobization of ionic carbon nitride (PHI) nanoparticles in the form of a composite with alkylated silica. The hydrophobized composite effectively photocatalyzes the reduction of dioxygen to H2O2 with concurrent oxidation of a model fatty alcohol (1-octanol) in the organic phase under visible light irradiation (406 nm LED), and enables, at the same time, facile separation of the high-value H2O2/water mixture from the reaction medium at H2O2 concentrations (~0.12 M) that are unprecedentedly high for light-driven systems reported in the literature. Notably, fatty alcohols are readily available from vegetable waxes and as pulping sub-products, and the products of their partial oxidation represent a valuable feedstock for the synthesis of pharmaceuticals and cosmetic products. This work thus showcases a rational design of a high-performance photocatalytic system for H2O2 production that enables easy separation of the product from electron donors and its recovery at high concentrations, and paves the way for sustainable and economically viable light-driven H2O2 production from easily available feedstock.
|
Igor Krivtsov; Ashish Vazirani; Dariusz Mitoraj; Mohamed M. Elnagar; Christof Neumann; Andrey Turchanin; Yolanda Patiño; Salvador Ordóñez; Robert Leiter; Mika Lindén; Ute Kaiser; Radim Beranek
|
Catalysis; Heterogeneous Catalysis; Photocatalysis; Materials Chemistry
|
CC BY 4.0
|
CHEMRXIV
|
2022-10-14
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/634833324b0af32776c4102f/original/hydrophobized-poly-heptazine-imide-for-highly-effective-photocatalytic-hydrogen-peroxide-production-in-a-biphasic-fatty-alcohol-water-system.pdf
|
624c00b1855ee57a8be291a3
|
10.26434/chemrxiv-2022-g44dj-v2
|
Systematic bottom-up molecular coarse-graining via force and torque matching using anisotropic particles
|
We derive a systematic and general method for parametrizing coarse-grained molecular models consisting of anisotropic particles from fine-grained (e.g. all-atom) models for condensed-phase molecular dynamics simulations. The method, which we call anisotropic force-matching coarse-graining (AFM-CG), is based on rigorous statistical mechanical principles, enforcing consistency between the coarse-grained and fine-grained phase-space distributions to derive equations for the coarse-grained forces, torques, masses, and moments of inertia in terms of properties of a condensed-phase fine-grained system. We verify the accuracy and efficiency of the method by coarse-graining liquid-state systems of two different anisotropic organic molecules, benzene and perylene, and show that the parametrized coarse-grained models more accurately describe properties of these systems than previous anisotropic coarse-grained models parametrized using other methods that do not account for finite-temperature and many-body effects on the condensed-phase coarse-grained interactions. The AFM-CG method will be useful for developing accurate and efficient dynamical simulation models of condensed-phase systems of molecules consisting of large, rigid, anisotropic fragments, such as liquid crystals, organic semiconductors, and nucleic acids.
|
David Huang; Huong Nguyen
|
Theoretical and Computational Chemistry
|
CC BY 4.0
|
CHEMRXIV
|
2022-04-05
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/624c00b1855ee57a8be291a3/original/systematic-bottom-up-molecular-coarse-graining-via-force-and-torque-matching-using-anisotropic-particles.pdf
|
677d9c3afa469535b91f909d
|
10.26434/chemrxiv-2025-1c3w4
|
Hot-Nucleic Acid Lateral Flow Assay (Hot-NALFA): A Novel Method for Point Mutation Detection
|
This study presents "hot-nucleic acid lateral flow assay" (Hot-NALFA), an innovative method for detecting point mutations in nucleic acid sequences. Hot-NALFA integrates the temperature-sensitive allelic discrimination properties of molecular beacons into a lateral flow assay format operating at elevated temperatures (~45–55°C). This approach enables end-point, visual detection of mutations, eliminating the requirement for real-time fluorescence instrumentation traditionally associated with molecular beacon-based allelic discrimination. The method exhibits high specificity, generating a visible test line exclusively in the presence of mutant targets. The technique was validated with synthetic sequences representing two clinically significant mutations: P681H in the S gene of SARS-CoV-2 and H526Y in the rpob gene of Mycobacterium tuberculosis. Optimal binary discrimination between wild-type and mutant sequences was achieved within the temperature range of 45–55°C for both mutations. By enabling direct allelic discrimination in a simple and cost-effective lateral flow assay format, Hot-NALFA addresses key limitations of current mutation detection methods and holds promise for point-of-care diagnostics.
|
Priyanka Agarwal; Shubham Agrawal; Bhushan Toley
|
Analytical Chemistry; Analytical Chemistry - General; Biochemical Analysis
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2025-01-09
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/677d9c3afa469535b91f909d/original/hot-nucleic-acid-lateral-flow-assay-hot-nalfa-a-novel-method-for-point-mutation-detection.pdf
|
66a3eb4701103d79c5c78d90
|
10.26434/chemrxiv-2024-r5bs1
|
Effect of Tautomerization in the Photophysics of 5-(thiophen-2-yl)-6-aza Uracil
|
In this study, we calculated the vertical excitation energies (VEEs) and spin-orbit coupling
constants (SOCs) of 5-(thiophen-2-yl)-6-aza uracil (TAU) and 2-methyl-5-(thiophen-2-yl)-6-aza
uracil (MTAU) using ground-state optimized geometries in two solvents: acetonitrile and water.
We then compared the theoretical and experimental absorption spectra for both modified 6-aza
uracil derivatives in these solvents. Methylation is used to prevent the 3-enol/5-enol
tautomerization observed in TAU and form the diketo tautomer. The aim is to determine if
methylation can be used as an effective strategy to avoid tautomerization of TAU without affecting
its photophysical properties. The experimental results and theoretical calculations demonstrated
that the addition of a methylated group does not change the photophysical properties of the
modified 6-Aza uracil.
|
Kamila Maldonado; Karitza Díaz-González; Sourav Seth; Carlos Crespo-Hernández
|
Physical Chemistry; Organic Chemistry; Photochemistry (Org.); Biophysical Chemistry
|
CC BY 4.0
|
CHEMRXIV
|
2024-07-31
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/66a3eb4701103d79c5c78d90/original/effect-of-tautomerization-in-the-photophysics-of-5-thiophen-2-yl-6-aza-uracil.pdf
|
62176d5e50b6213987de7219
|
10.26434/chemrxiv-2022-qwcjz
|
Sulfur-assisted urea synthesis from carbon monoxide and ammonia in water
|
Efficient conversion of carbon monoxide into urea in an aqueous ammonia solution was demonstrated through coupling with the elemental sulfur reduction to polysulfides. Polysulfides control the overall reaction rate while suppressing the accumulation of a by-product, hydrogen sulfide. These functions follow basic kinetic and thermodynamic theories, enabling prediction-based reaction control. This operational merit, together with the superiority of water as a green solvent, suggests that our demonstrated urea synthesis is a promising option for sulfur utilization beneficial for agricultural production.
|
Norio Kitadai; Satoshi Okada; Akiko Makabe; Eiji Tasumi; Masayuki Miyazaki
|
Organic Chemistry; Agriculture and Food Chemistry; Organic Synthesis and Reactions
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2022-02-25
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/62176d5e50b6213987de7219/original/sulfur-assisted-urea-synthesis-from-carbon-monoxide-and-ammonia-in-water.pdf
|
661030e691aefa6ce1e33513
|
10.26434/chemrxiv-2024-x7rkm
|
An Abiotic Phospholipid Metabolic Network Facilitates Membrane Plasticity in Artificial Cells
|
The plasticity of living cell membranes relies on complex metabolic networks fueled by cellular energy. Although lipid vesicles have been extensively studied, creating synthetic membranes capable of metabolic cycles remains unrealized. Here we present an abiotic phospholipid metabolic network that generates and maintains dynamic artificial cell membranes. Chemical coupling agents drive the in situ synthesis of transiently stable non-canonical phospholipids, leading to the formation and maintenance of phospholipid membranes. Phospholipid metabolic cycles are capable of driving lipid self-selection and controlling lipid metabolism can induce reversible membrane phase transitions, triggering membrane fusion and lipid mixing. Our work demonstrates that simple lipid metabolic networks can produce artificial cells with lifelike properties, offering insights into mechanisms for engineering synthetic membrane dynamics.
|
Alessandro Fracassi; Andrés Seoane; Roberto Brea; Neal Devaraj
|
Biological and Medicinal Chemistry
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2024-04-08
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/661030e691aefa6ce1e33513/original/an-abiotic-phospholipid-metabolic-network-facilitates-membrane-plasticity-in-artificial-cells.pdf
|
66c9513cf3f4b05290ec71ef
|
10.26434/chemrxiv-2024-7vg64
|
Environment- and Conformation-Induced Frequency Shifts of C–D Vibrational Stark Probes in NAD(P)H Cofactors
|
NAD(P)H cofactors are found in all forms of life and are essential for electron and hydrogen atom transfer. The linear response of a carbon-deuterium (C–D) vibration based on the vibrational Stark effect can facilitate measurements of electric fields for critical biological reactions including cofactor-mediated hydride transfer. We find both inter- and intramolecular electric fields influence the C–D frequency in NAD(P)H and nicotinamide-like models where the reactive C4-hydrogen has been deuterated. Hence, the C–D frequency can report both environmental electrostatics and conformational changes of the nicotinamide ring. Conformation-dependent effects are mediated through space as electrostatic effects, rather than through-bond. A Stark tuning rate of ~0.57 cm-1/(MV/cm) was determined using both experimental and computational approaches, including vibrational solvatochromism, molecular dynamics simulations, and in-silico Stark calculations. The vibrational probe’s Stark tuning rate is shown to be robust and suitable for measuring fields along hydride transfer reaction coordinates in enzymes
|
Steven Fried; Srijit Mukherjee; Yuezhi Mao; Steven Boxer
|
Physical Chemistry; Biophysical Chemistry; Spectroscopy (Physical Chem.)
|
CC BY NC 4.0
|
CHEMRXIV
|
2024-08-26
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/66c9513cf3f4b05290ec71ef/original/environment-and-conformation-induced-frequency-shifts-of-c-d-vibrational-stark-probes-in-nad-p-h-cofactors.pdf
|
60c73e0f702a9b8a45189cac
|
10.26434/chemrxiv.5314828.v2
|
Systematic comparison of Amber and Rosetta energy functions for protein structure evaluation.
|
<p>An accurate energy function is an essential component of biomolecular
structural modeling and design. The
comparison of differently derived energy functions enables analysis of the
strengths and weaknesses of each energy function, and provides independent
benchmarks for evaluating improvements within a given energy function. We compared the molecular mechanics Amber
empirical energy function to two versions of the Rosetta energy function
(talaris2014 and REF2015) in decoy discrimination and loop modeling tests. Both
Rosetta's talaris2014 and Amber's ff14SBonlySC energy functions performed well
in scoring the native state as the lowest energy conformation in many cases. In 24/150 cases with Rosetta, and in 2/150
cases using Amber, a false minimum is found that is absent in the alternative
landscape. In 21/150 cases, both energy function-generated landscapes featured
false minima. The newest version of the Rosetta energy function, REF2015, which
has more physically-derived terms than talaris2014, performs significantly
better, highlighting the improvements made to the Rosetta scoring approach. To
take advantage of the semi-orthogonal nature of these energy functions, we developed
a Pareto optimization approach that combines Amber and Rosetta energy
landscapes to predict the most near-native model for a given protein. This algorithm
improves upon predictions from either energy function in isolation, and should
aid in model selection for structure prediction and loop modeling tasks. </p>
|
Aliza Rubenstein; Kristin Blacklock; Hai Nguyen; David Case; Sagar Khare
|
Computational Chemistry and Modeling
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2018-04-04
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c73e0f702a9b8a45189cac/original/systematic-comparison-of-amber-and-rosetta-energy-functions-for-protein-structure-evaluation.pdf
|
60c74ade0f50db7d51396b30
|
10.26434/chemrxiv.12220418.v2
|
Liquid Crystal Coacervates Composed of Short Double Stranded DNA and Cationic Peptides
|
<p>Phase separation of nucleic acids and proteins is a ubiquitous phenomenon regulating sub-cellular compartment structure and function. While complex coacervation of flexible single stranded nucleic acids is broadly investigated, coacervation of double stranded DNA (dsDNA) is less studied because of its propensity to generate solid precipitates. Here, we reverse this perspective by showing that short dsDNA and poly-L-lysine coacervates can escape precipitation while displaying a surprisingly complex phase diagram, including the full set of liquid crystal (LC) mesophases observed to date in bulk dsDNA. LC-coacervate structure was characterized upon variations in temperature and monovalent salt, DNA and peptide concentrations, which allow continuous transitions between all accessible phases. A deeper understanding of LC-coacervates can gain insights to decipher structures and phase transition mechanisms within biomolecular condensates, to design stimuli-responsive multi-phase synthetic compartments with different degrees of order and to exploit self-assembly driven cooperative prebiotic evolution of nucleic acids and peptides.</p>
|
Tommaso Fraccia; Tony Z. Jia
|
Biological Materials; Liquid Crystals; Polyelectrolytes - Polymers; Self-Assembly
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2020-04-30
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74ade0f50db7d51396b30/original/liquid-crystal-coacervates-composed-of-short-double-stranded-dna-and-cationic-peptides.pdf
|
6525264a45aaa5fdbbadc2ef
|
10.26434/chemrxiv-2023-rs2zh
|
C-H Chalcogenation by a Bromide Rich and Environmentally Benign Orthorhombic CsPbBr3 under Visible Light, Polar Media and Aerobic Condition
|
The stability of CsPbBr3 nanocrystals (NCs) in open air remains challenging and can vary depending on the specific material and conditions. Generally, perovskites are prone to degradation due to oxygen, moisture, polar solvent, and light exposure. In this work, we have aimed to develop strategies to improve the stability of CsPbBr3 perovskite and broaden its potential applications in organic synthesis. An orthorhombic CsPbBr3 perovskite nano-crystal (NC) obtained from bromide precursor dibromoisocyanuric acid, can work efficiently as a visible light photocatalyst (blue LED, 5 mol % and TON ~ 18.11) under O2 atmosphere and in acetonitrile (dielectric constant ε ~ 37.5). The synthesis of diaryl sulfides and a diaryl selenide were achieved via template-free C-H functionalization of electron-rich arenes. The electron-rich arenes also helped to enhance the stability of the CsPbBr3 perovskites photocatalyst within the reaction system. The orthorhombic and bromide-rich CsPbBr3 NC displayed superior photocatalytic activity than cubic CsPbBr3 NCs and was found to be environmentally benign. After the reaction, only 32 ppb of Pb(II) was leached out (ICP-OES analysis) which is quite lower than the maximum permissible limit for drinking water of humans (50 ppb).
|
Ashis Mathuri; Buddhadeb Pal ; MILAN PRAMANIK; Anupam Manna; Prasenjit Mal
|
Organic Chemistry; Photochemistry (Org.); Materials Chemistry
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2023-10-11
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6525264a45aaa5fdbbadc2ef/original/c-h-chalcogenation-by-a-bromide-rich-and-environmentally-benign-orthorhombic-cs-pb-br3-under-visible-light-polar-media-and-aerobic-condition.pdf
|
65cacb669138d23161fa546e
|
10.26434/chemrxiv-2024-rp8s5
|
Total Synthesis of Cephanolide A and Harringtonolide: A Unified Strategy Connecting Benzenoid and Troponoid Cephalotaxus Diterpenoids
|
The fascinating benzenoid and troponoid Cephalotaxus diterpenoids are highly related biosynthetically, both of which are popular targets for total synthesis. Herein, we describe a unified strategy for the concise synthesis of cephanolide A and harringtonolide in 14 and 16 steps respectively. Palladium catalyzed Csp2-Csp3 cross-coupling followed by doubly electron-deficient intramolecular Diels-Alder reaction secure the rapid construction of the Cephalotaxus carbon framework. Late-stage benzenoid-to-troponoid ring expansion was accomplished employing Büchner-Curtius-Schlotterbeck (BCS) reaction, furnishing harringtonolide in two steps from cephanolide A. This work shed light on the chemical synthetic connection between benzenoid and troponoid Cephalotaxus diterpenoids.
|
Zi-An Zhang; Xu-cheng Gan; Guang Tian; Xiao-Yu Shi; Chuanguang Qin; Jie Wang
|
Organic Chemistry; Natural Products
|
CC BY NC 4.0
|
CHEMRXIV
|
2024-02-14
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/65cacb669138d23161fa546e/original/total-synthesis-of-cephanolide-a-and-harringtonolide-a-unified-strategy-connecting-benzenoid-and-troponoid-cephalotaxus-diterpenoids.pdf
|
60c73cc9bdbb897866a37b7b
|
10.26434/chemrxiv.14738109.v1
|
Towards a Practical, Non-enzymatic Process for Molnupiravir from Cytidine
|
A scalable four step synthesis of molnupiravir from
cytidine is described herein. The attractiveness of this approach is its fully
chemical nature involving inexpensive reagents and more environmentally
friendly solvents such as water, isopropanol, acetonitrile and acetone. Isolation
and purification procedures are improved in comparison to our earlier report,
as all intermediates can be isolated via aqueous acid treatment and recrystallization. The key steps in
the synthesis, namely ester formation, hydroxamination and deprotection were
done on multigram scale to afford molnupiravir in 36-41% yield with average purity
of 98 wt% by q-NMR and 99 area % by HPLC
|
Vijayagopal Gopalsamuthiram; Appasaheb L. Kadam; Jeffrey Noble; David Snead; Corshai Williams; Timothy F. Jamison; Chris Senanayake; Ajay Yadaw; Sarabindu Roy; Gopal Sirasani; B. Frank Gupton; Justina Burns; Daniel W. Cook; Rodger W. Stringham; Saeed Ahmad; Rudy Krack
|
Process Chemistry
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2021-06-08
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c73cc9bdbb897866a37b7b/original/towards-a-practical-non-enzymatic-process-for-molnupiravir-from-cytidine.pdf
|
64ca3c65dfabaf06ff93d1ed
|
10.26434/chemrxiv-2023-8dvg5
|
Preparation of "mycelium pulp" from mushroom fruiting bodies
|
In this study, we developed a new method to extract mycelial fibers from the fruiting bodies of mushrooms without destroying their structure. After chemical treatment with NaOH and H<sub>2</sub>O<sub>2</sub>, the fruiting bodies were decolorized via an environmentally friendly method using sunlight irradiation. The visible light reflectance of decolorized fruiting bodies was more than 80%. Ultrasonic treatment was used to defibrillate the fruiting bodies at the mycelial level, and a white micrometer-sized dispersion of mycelial fibers (mycelium pulp) was obtained. The mycelium retained its structure, demonstrating a thick linear mycelium pulp (width: 8.0 ± 3.4 μm) in <i>Flammulina velutipes<i> and a thin branched mycelium pulp (width: 2.3 ± 0.6 μm) in <i>Ganoderma lucidum<i>. The mycelium pulp is a completely new material that maintains its mycelial structure, unlike previously reported materials derived from fruiting bodies. The mycelium pulp demonstrates excellent deformability and can be used to create one- to three-dimensional deformable products, showing a wide range of material applicability.
|
Hiroya Nakauchi; Satomi Tagawa; Yoshihiko Amano
|
Materials Science; Biological Materials; Fibers; Materials Chemistry
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2023-08-09
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/64ca3c65dfabaf06ff93d1ed/original/preparation-of-mycelium-pulp-from-mushroom-fruiting-bodies.pdf
|
6734adca7be152b1d0f3f458
|
10.26434/chemrxiv-2024-8p4fv
|
Digging through the (statistical) dirt: A reproducible method for single-molecule flicker noise analysis
|
Flicker noise analysis has found widespread use in the molecular electronics community over the past 9
years. The noise power of the junctions and the value of its scaling exponent 𝑛 provide information on the
spatial overlap of scattering states in single-molecule junctions and give unique insights into quantum
transport phenomena at the single-molecule level. The predominant drawback of this analytical tool is the
inconsistency of the methodologies employed, resulting in irreproducibility across datasets acquired in
different conditions or in different laboratories. Herein, we provide a pathway to a more reproducible
methodology, detailing issues with the currently accepted correlation techniques employed and introduce the
use of more statistically robust data processing criteria and lower thresholds for data acquisition parameters.
|
James Morris; Jarred Potter; Demetris Bates; Chuanli Wu; Craig Robertson; Simon Higgins; Richard Nichols; Paul Low; Andrea Vezzoli
|
Physical Chemistry; Nanoscience; Nanodevices; Transport phenomena (Physical Chem.)
|
CC BY NC 4.0
|
CHEMRXIV
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2024-11-15
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https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6734adca7be152b1d0f3f458/original/digging-through-the-statistical-dirt-a-reproducible-method-for-single-molecule-flicker-noise-analysis.pdf
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65a7628d66c13817299f6c39
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10.26434/chemrxiv-2024-njlv5
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Caged Gold Nanostars: A novel plasmonic nanoplatform with theranostics applications
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Here, we first introduce caged gold nanostars (C-GNS), a novel hybrid nanoplatform combining the exceptional plasmonic properties of nanostars with the loading capability of hollow-shell structures. We present two synthetic routes used to produce C-GNS particles and highlight the benefits of the galvanic replacement-free approach. FEM simulations explore the enhanced plasmonic properties of this novel nanoparticle morphology. Finally, in a proof-of-concept study, we successfully demonstrate in vivo hyperspectral imaging and photothermal treatment of tumors in a mouse model with the C-GNS nanoplatform.
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Aidan Canning; Tuan Vo-Dinh
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Nanoscience; Nanostructured Materials - Nanoscience; Plasmonic and Photonic Structures and Devices
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CC BY NC ND 4.0
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CHEMRXIV
|
2024-01-18
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/65a7628d66c13817299f6c39/original/caged-gold-nanostars-a-novel-plasmonic-nanoplatform-with-theranostics-applications.pdf
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6684ae6f5101a2ffa837f52d
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10.26434/chemrxiv-2024-kmjgl
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Fundamentally Intertwined: Anharmonic Intermolecular Interactions Dictate Both Thermal Expansion and Terahertz Lattice Dynamics in Molecular Crystals
|
We investigate the anisotropic thermal expansion behavior of a co-crystalline system composed of 4,4’-azopyridine and trimesic acid (TMA-azo). Using variable-temperature single-crystal X-ray diffraction (SC-XRD), low-frequency Raman spectroscopy, and terahertz time-domain spectroscopy (THz-TDS), we observe significant temperature-induced shifting and broadening of the vibrational absorption features, indicating changes in the intermolecular potential and dynamics. Our findings reveal that thermal expansion is driven by anharmonic interactions and the potential energy topography, rather than increased molecular dynamics. Density functional theory (DFT) simulations support these results, highlighting significant softening of the potential energy surface (PES) with temperature. This comprehensive approach offers valuable insights into the relationship between structural dynamics and thermal properties, providing a robust framework for designing materials with tailored thermal expansion characteristics.
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Navkiran Juneja; Josephine Hastings; William Stoll; William Brennessel; Salvatore Zarella; Parker Sornberger; Luca Catalano; Timothy Korter; Michael Ruggiero
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Theoretical and Computational Chemistry; Physical Chemistry; Physical and Chemical Properties; Spectroscopy (Physical Chem.); Materials Chemistry; Crystallography
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CC BY NC ND 4.0
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CHEMRXIV
|
2024-07-04
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6684ae6f5101a2ffa837f52d/original/fundamentally-intertwined-anharmonic-intermolecular-interactions-dictate-both-thermal-expansion-and-terahertz-lattice-dynamics-in-molecular-crystals.pdf
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60c7504d567dfe6f1cec5837
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10.26434/chemrxiv.13019117.v1
|
Speed-Dependent Adaptive Partitioning QM/MM for Displacement Damage Simulations
|
Solids receive displacement damages (DD) when interacting with energetic particles, which may happen during the fabrication of semiconductor devices, in harsh environments and in certain analysis techniques. Simulations of the DD generation are usually carried out with classical molecular dynamics (MD), but classical MD does not account for all the effects in DD, as demonstrated by <i>ab initio</i> calculations of model systems in literature. A fully <i>ab initio</i> simulation of the DD generation is impractical due to the large number of atoms involved. In my previous paper [Phys. Chem. Chem. Phys. 22, 19307 (2020)], I developed an adaptive-center (AC) method for adaptive-partitioning (AP) quantum mechanics/molecular mechanics (QM/MM) simulations, allowing the active region centers and the QM/MM partition to be determined on-the-fly for energy-conserving AP-QM/MM methods. I demonstrated that the AC-AP-QM/MM is applicable to the simulation of the DD generation, so that the active regions can be treated with an <i>ab initio</i> method. The AC method was unable to identify the fast-moving recoil ions in the DD generation as active region centers, however, and the accuracy is negatively affected by the rapid change in QM/MM partition of the system. In this paper, I extend the AC method and develop a speed-dependent adaptive-center (SDAC) method for proper AP-QM/MM simulations of DD. The SDAC method is applicable to general problems with speed-dependent active regions, and is compatible with all existing energy-conserving partition-by-distance AP-QM/MM methods. The artifact due to the speed-dependent potential energy surface can be made small by choosing proper criteria. I demonstrate the SDAC method by simulations of the DD generation in bulk Silicon.<br />
|
Zenghui Yang
|
Computational Chemistry and Modeling
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CC BY NC ND 4.0
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CHEMRXIV
|
2020-09-30
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c7504d567dfe6f1cec5837/original/speed-dependent-adaptive-partitioning-qm-mm-for-displacement-damage-simulations.pdf
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653ffac8c573f893f1748f3a
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10.26434/chemrxiv-2023-4x7kx
|
Structure and dynamics of liquid water from ab initio simulations: Adding Minnesota density functionals to Jacob’s ladder
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The accurate representation of the structural and dynamical properties of water is essential for simulating the unique behavior of this ubiquitous solvent. Here we assess the current status of describing liquid water using ab initio molecular dynamics, with a special focus on the performance of all the later generation Minnesota functionals. Findings are contextualized within the current knowledge on DFT for describing bulk water under ambient conditions and compared to experimental data. We find that, contrary to the prevalent idea that local and semilocal functionals overstructure water and underestimate dynamical properties, M06-L, revM06-L, and M11-L understructure water, while MN12-L and MN15-L overdistance water molecules due to weak cohesive effects. This can be attributed to a weakening of the hydrogen bond network, which leads to dynamical fingerprints that are over fast. While most of the hybrid Minnesota functionals (M06, M08-HX, M08-SO, M11, MN12- SX, and MN15) also yield understructured water, their dynamical properties generally improve over their semilocal counterparts. It emerges that exact exchange is a crucial component for accurately describing hydrogen bonds, which ultimately leads to corrections in both the dynamical and structural properties. However, an excessive amount of exact exchange strengthens hydrogen bonds and causes overstructuring and slow dynamics (M06-HF). As a compromise, M06-2X is the best performing Minnesota functional for water, and its D3 corrected variant shows very good structural agreement. From previous studies considering nuclear quantum effects (NQEs), the hybrid revPBE0-D3, and the rung-5 RPA (RPA@PBE) have been identified as the only two approximations that closely agree with experiments. Our results suggest that the M06-2X(-D3) functionals have the potential to further improve the reproduction of experimental properties when incorporating NQEs through path integral approaches. This work provides further proof that accurate modeling of water interactions requires the inclusion of both exact exchange and balanced (non-local) correlation, highlighting the need for higher rungs on Jacob’s ladder to achieve predictive simulations of complex biological systems in aqueous environments.
|
Justin Villard; Ursula Rothlisberger
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Theoretical and Computational Chemistry
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CC BY 4.0
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CHEMRXIV
|
2023-10-31
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https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/653ffac8c573f893f1748f3a/original/structure-and-dynamics-of-liquid-water-from-ab-initio-simulations-adding-minnesota-density-functionals-to-jacob-s-ladder.pdf
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674999377be152b1d0566ec8
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10.26434/chemrxiv-2024-gx2q5
|
Detection of Western Diamondback Rattlesnake (C. atrox) venom using Glycopolymer Functionalised Gold Nanoparticles
|
Every 5 minutes, 50 people are bitten by a snake worldwide, four will be permanently disabled and one will die.1,2 Most approaches to treating and diagnosing snake envenomation rely on antibody-based solutions. Here, we present a proof-of-concept for a glycan-based UV-vis assay to detect Crotalus atrox (C. atrox) venom versus model proteins and Indian Cobra (Naja naja, N. naja) venom.
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Mahdi Hezwani; Derecash Anokye; Douglas E. Soutar; Melissa Ligorio; Neil Prabhakar; Alexander Cantor; Roberto Terracciano; Marc Walker; Alexander N. Baker
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Biological and Medicinal Chemistry; Polymer Science; Bioengineering and Biotechnology; Materials Chemistry
|
CC BY NC 4.0
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CHEMRXIV
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2024-12-02
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/674999377be152b1d0566ec8/original/detection-of-western-diamondback-rattlesnake-c-atrox-venom-using-glycopolymer-functionalised-gold-nanoparticles.pdf
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60c745b4f96a00d394286c19
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10.26434/chemrxiv.10110536.v1
|
Convergent Synthesis of Trisubstituted Tetrahydrofurans via Bis-Thermally Reactive 1,5-Diene-Tert-Butyl Carbonates.
|
<p>Cascade reactions (also known as domino- or
tandem reactions) are an efficient strategy for generating molecular complexity.
We report that synergizing the thermal reactivity of 3,3-dicyano-1,5-dienes and
<i>tert</i>-butyl carbonates result in stereospecific 2,3,4-trisubstituted
tetrahydrofuran synthesis. While substituted tetrahydrofurans can be
challenging to synthesize, this discovery converts readily available 1,5-dienes
derived from aldehydes, malononitrile, and <i>cis</i>-buten-1,4-diol into complex tetrahydrofurans <i>via </i>a process
involving <i>thermal </i>Cope rearrangement, Boc-deprotection, and <i>oxy</i>-Michael
addition. Described herein includes background related to the discovery,
optimization and scope, and representative functional group interconversion
chemistry for the scaffolds. </p>
|
Alex Grenning; Fabien Emmetiere
|
Organic Synthesis and Reactions
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CC BY NC ND 4.0
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CHEMRXIV
|
2019-11-06
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c745b4f96a00d394286c19/original/convergent-synthesis-of-trisubstituted-tetrahydrofurans-via-bis-thermally-reactive-1-5-diene-tert-butyl-carbonates.pdf
|
65e1d0ee9138d231616bcc22
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10.26434/chemrxiv-2024-rs3lh
|
Silicon-tethered colchicine aryne cyclo-adduct as a potent molecule for the abrogation of epithelial to mesenchymal transition via modulating cell cycle regulatory CDK-2 and CDK-4 kinases
|
The anticancer potential of colchicine and its derivatives has garnered significant attention due to their ability to bind with tubulin, a critical cytoskeletal protein crucial for cell division's mitotic phase. In this study, we synthesized a new-generation library of colchicine derivatives via cycloaddition of colchicine utilizing position C-8 and C-12 diene system regioselectivity with aryne precursor to generate a small focussed library of derivatives. We assessed their anticancer activity against various cancer cell lines like MCF-7, MDA-MB-231, MDA-MB-453, and PC-3. Normal human embryonic kidney cell line HEK-293 was used to determine the toxicity. Among these derivatives, the silicon-tethered compound B-4a demonstrated the highest potency against breast cancer cells. Subsequent mechanistic studies revealed that B-4a effectively modulates cell cycle regulatory kinases (cdk-2 and cdk-4) and their associated cyclins (cyclin B1, cyclin D1), inducing apoptosis.
Additionally, B-4a displayed a noteworthy impact on tubulin polymerization, distinct from the parent colchicine, and significantly disrupted the vimentin cytoskeleton, contributing to G1 arrest in breast cancer cells. Moreover, B-4a exhibited substantial anti-metastatic properties by inhibiting breast cancer cell migration and invasion. These effects were attributed to the down-regulation of major epithelial to mesenchymal transition (EMT) factors, including Vimentin and Twist-1, as well as the upregulation of the epithelial marker E-cadherin in an apoptosis-dependent manner.
|
Waseem Lone; Jagdish Chand ; Puneet Kumar; Zabeer Ahmed ; Anindya Goswami ; Jasha Momo H. Anal
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Biological and Medicinal Chemistry; Organic Chemistry; Natural Products; Cell and Molecular Biology; Drug Discovery and Drug Delivery Systems
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2024-03-04
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/65e1d0ee9138d231616bcc22/original/silicon-tethered-colchicine-aryne-cyclo-adduct-as-a-potent-molecule-for-the-abrogation-of-epithelial-to-mesenchymal-transition-via-modulating-cell-cycle-regulatory-cdk-2-and-cdk-4-kinases.pdf
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663be41f91aefa6ce184835b
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10.26434/chemrxiv-2024-qx3wv
|
Hierarchical Assembly and Environmental Enhancement of Bacterial Ice Nucleators
|
Bacterial ice nucleating proteins (INPs) are exceptionally effective in promoting the kinetically hindered transition of water to ice. Their efficiency relies on the assembly of INPs into large functional aggregates, with the size of ice nucleation sites determining activity. Experimental freezing spectra have revealed two distinct, defined aggregate sizes, typically classified as class A and C ice nucleators (INs). Despite the importance of INPs and years of extensive research, the precise number of INPs forming the two aggregate classes and their assembly mechanism have remained enigmatic. Here, we report that bacterial ice nucleation activity emerges from more than two prevailing aggregate species and identify the specific number of INPs responsible for distinct crystallization temperatures. We find that INP dimers constitute class C INs, tetramers class B INs, and hexamers and larger multimers are responsible for the most efficient class A activity. We propose a hierarchical assembly mechanism based on tyrosine interactions for dimers, and electrostatic interactions between INP dimers to produce larger aggregates. This assembly is membrane-assisted: increasing the bacterial outer membrane fluidity decreases the population of the larger aggregates, while preserving the dimers. Inversely, DPBS buffer increases the population of multimeric class A and B aggregates 200-fold and endows the bacteria with enhanced stability towards repeated freeze-thaw cycles. Our analysis suggests that the enhancement results from the better alignment of dimers in the negatively charged outer membrane, due to screening of their electrostatic repulsion. This constitutes the first demonstration of enhancement of the most potent bacterial INs.
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Galit Renzer; Ingrid de Almeida Ribeiro; Hao-Bo Guo; Janine Fröhlich-Nowoisky; Rajiv Berry; Mischa Bonn; Valeria Molinero; Konrad Meister
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Physical Chemistry; Earth, Space, and Environmental Chemistry; Atmospheric Chemistry; Biophysical Chemistry
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2024-05-10
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/663be41f91aefa6ce184835b/original/hierarchical-assembly-and-environmental-enhancement-of-bacterial-ice-nucleators.pdf
|
60c7571a9abda24005f8e624
|
10.26434/chemrxiv.14370764.v1
|
Simulation Meets Experiment: Unraveling the Properties of Water in Metal-Organic Frameworks Through Vibrational Spectroscopy
|
<div>
<div>
<div>
<p>In nanoporous materials, guest–host interactions affect the properties and function of
both adsorbent and adsorbate molecules. Due to their structural and chemical diversity, metal-organic frameworks (MOFs), a common class of nanoporous materials, have
been shown to be able to efficiently and, often, selectively adsorb various types of guest
molecules. In this study, we characterize the structure and dynamics of water confined
in ZIF-90. Through the integration of experimental and computational infrared (IR) spectroscopy, we probe the structure of heavy water (D<sub>2</sub>O) adsorbed in the pores,
disentangling the fundamental framework–water and water–water interactions. The experimental IR spectrum of D<sub>2</sub>O in ZIF-90 displays a blue-shifted OD-stretch band
compared to liquid D<sub>2</sub>O. The analysis of the IR spectra simulated at both classical
and quantum levels indicates that the D<sub>2</sub>O molecules preferentially interact with the
carbonyl groups of the framework and highlights the importance of including nuclear
quantum effects and taking into account Fermi resonances for a correct interpretation
of the OD-stretch band in terms of the underlying hydrogen-bonding motifs. Through
a systematic comparison with the experimental spectra, we demonstrate that computational spectroscopy can be used to gain quantitative, molecular-level insights into
framework–water interactions that determine the water adsorption capacity of MOFs
as well as the spatial arrangements of the water molecules inside the MOF pores which,
in turn, are key to the design of MOF-based materials for water harvesting.</p>
</div>
</div>
</div>
|
Kelly M. Hunter; Jackson Wagner; Mark Kalaj; Wei Xiong; Paesani Lab; Francesco Paesani
|
Computational Chemistry and Modeling; Theory - Computational; Physical and Chemical Properties; Spectroscopy (Physical Chem.); Statistical Mechanics; Thermodynamics (Physical Chem.); Materials Chemistry
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2021-04-06
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c7571a9abda24005f8e624/original/simulation-meets-experiment-unraveling-the-properties-of-water-in-metal-organic-frameworks-through-vibrational-spectroscopy.pdf
|
60c7432e4c89190610ad25c3
|
10.26434/chemrxiv.8956919.v1
|
Symmetry-Adapted Perturbation Theory Decomposition of the Reaction Force: Insights into Substituent Effects Involved in Hemiacetal Formation Mechanisms
|
<div>The decomposition of the reaction force based on symmetry-adapted perturbation theory (SAPT) has been proposed. This approach was used to investigate the subtituent effects along the reaction coordinate pathway for the hemiacetal formation mechanism between methanol and substituted aldehydes of the form CX<sub>3</sub>CHO (X = H, F, Cl, and Br), providing a quantitative evaluation of the reaction-driving and reaction-retarding force components. Our results highlight the importance of more favorable electrostatic and induction effects in the reactions involving halogenated aldehydes that leads to lower activation energy barriers. These substituent effects are further elucidated by applying the functional-group partition of symmetry-adapted</div><div>perturbation theory (F-SAPT). The results show that the reaction is largely driven by favorable direct non-covalent interactions between the CX<sub>3</sub> group on the aldehyde and the OH group on methanol.</div>
|
Wallace Derricotte
|
Theory - Computational
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2019-07-22
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c7432e4c89190610ad25c3/original/symmetry-adapted-perturbation-theory-decomposition-of-the-reaction-force-insights-into-substituent-effects-involved-in-hemiacetal-formation-mechanisms.pdf
|
6577ca997acf130c3206bb37
|
10.26434/chemrxiv-2023-s8kps-v2
|
Development of Repetitive Synergism in Calitropis procera Extract with Ampicillin for Combating Drug Resistance in Clinical Bacteria and Identification of its Bioactive Components using GS-MS Analysis.
|
The pursuit of innovative approaches to develop lead compounds that exhibit selectivity, efficacy, and safety as potential candidates for clinical trials poses a significant scientific challenge. Natural products, with their inherent diversity, offer unique pharmacophores, chemotypes, and scaffolds that can be harnessed to create effective drugs targeting various infections and diseases. This study introduces a straightforward, rudimentary, and environmentally sustainable method to enhance the antimicrobial activity of two less potent antimicrobial agents, fostering consistent and repetitive synergism against drug-resistant clinical bacteria. The aqueous extract of fresh leaves and flowers of Calotropis procera was subjected to a reaction with a 1 mg/mL ampicillin solution under heat and acidic conditions. The resultant sample exhibited pronounced synergy and heightened susceptibility against resistant strains of Staphylococcus aureus and Salmonella spp, augmenting their zones of inhibition from 0 mm to 16.8 mm and from 5.3 mm to 21.4 mm, respectively. Utilizing gas chromatography-mass spectrometry (GC-MS) analysis, the study identified 53 phytochemicals in the extract, with oleic acid (13.04%), 1,1,1,3,5,5,7,7,7-nonamethyl-3-(trimethylsiloxy) tetrasiloxane (9.50%), 9-heptadecanone (3.75%), cystamine (3.35%), and tetrahydro-4H-pyran-4-ol (3.15%) emerging as the top five most abundant phytochemicals. Notably, 18 out of the 53 phytochemicals were associated with known biological activities. Some underwent molecular transformations, generating new molecules or analogues of existing biologically active compounds under the reaction conditions applied. The analysis revealed the discovery of compounds such as farnesol, cystamine, cystine, metaraminol, dl-phenylephrine, and two distinct substituted amphetamine compounds. Three phytochemicals demonstrated anticancer properties, namely farnesol, 4-amino-1-pentanol, and an imidazole derivative resembling the drug Ribavir. The study's findings underscore the potential of medicinal plant phytochemicals in synthetic combination reactions, either with themselves or other drugs/reagents, to yield a diverse array of compounds exhibiting significant pharmacological activities. These compounds may serve as valuable starting materials, intermediates, or derivatives in pharmaceutical production.
|
Mathew Gideon; Zakari Ladan; Yahaya Yakubu
|
Biological and Medicinal Chemistry; Organic Chemistry; Chemical Engineering and Industrial Chemistry; Bioorganic Chemistry; Combinatorial Chemistry; Drug Discovery and Drug Delivery Systems
|
CC BY 4.0
|
CHEMRXIV
|
2023-12-12
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6577ca997acf130c3206bb37/original/development-of-repetitive-synergism-in-calitropis-procera-extract-with-ampicillin-for-combating-drug-resistance-in-clinical-bacteria-and-identification-of-its-bioactive-components-using-gs-ms-analysis.pdf
|
62fa51141d6a99444404ee84
|
10.26434/chemrxiv-2022-587qb
|
Photoactive surfactant semiconductors characterized by a dissociative identity disorder integrated into the membranes of living cells as trojan horses for on-demand and spatial regulation of oxidative stress.
|
Oxidative stress is a cause for numerous diseases and aging processes. Thus, one is keen to tune the level of intracellular stress and to learn from that, and an unusual approach is presented here. The methodology involves multifunctional surfactants. Although their molecular design is non-biological, a fullerenol head group attached covalently to -conjugated dyes, the surfactants possess superior biocompatibility. Using the intrinsic fluorescence signal as a probe it is proven, the amphiphiles become incorporated into the membranes of Caco-2 cells. There, they are able to exhibit additional functions. The compound reduces cellular stress in dark reaction pathways. The antagonistic property is activated under irradiation, the photocatalytic production of ROS, resulting in cell damage and finally to apoptosis. The feature is activated even by NIR-light via a two-photon process. The properties as molecular semiconductors leads to a trojan horse situation and allows programming the spatial distribution of cytotoxicity.
|
Marian Jaschke; Masina Plenge; Marius Kunkel; Tina Lehrich; Julia Schmidt; Kilian Stöckemann; Dag Heinemann; Stephan Siroky; Anaclet Ngezahay; Sebastian Polarz
|
Biological and Medicinal Chemistry; Organic Chemistry; Photochemistry (Org.); Cell and Molecular Biology; Materials Chemistry
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2022-08-16
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/62fa51141d6a99444404ee84/original/photoactive-surfactant-semiconductors-characterized-by-a-dissociative-identity-disorder-integrated-into-the-membranes-of-living-cells-as-trojan-horses-for-on-demand-and-spatial-regulation-of-oxidative-stress.pdf
|
60c757b29abda20e04f8e7b7
|
10.26434/chemrxiv.14451117.v1
|
Ligand-to-Copper Charge Transfer: A General Catalytic Approach to Aromatic Decarboxylative Functionalization
|
<p>Aryl carboxylic acids are valuable, stable, and abundant functional handles in organic synthesis. Historically, their activation with established two-electron methods requires forcing conditions, and such protocols are limited in scope. In contrast, we envisioned that copper’s ability to generate open-shell species through ligand-to-metal charge transfer (LMCT), combined with its unique capacity to act as a potential aroyloxy and aryl radical reservoir, could mediate facile light- and copper-enabled aromatic decarboxylative functionalization by mitigating undesired reactivity of radical intermediates formed during aromatic decarboxylation. We report herein a general copper-LMCT open-shell activation platform for aromatic halodecarboxylation. Catalytic decarboxylative chlorination, bromination, and iodination of diverse (hetero)aryl carboxylic acids have been achieved to provide broadly used electrophilic cross-coupling handles from widely available aromatic acid precursors. Notably, decarboxylative fluorination of aryl carboxylic acids – a long-standing challenge in the field of organic synthesis – is readily accessible over a wide breadth of (hetero)aryl substrates. Ultrafast transient absorption (TA) spectroscopy experiments in combination with steady-state UV-vis spectroscopy studies are consistent with the proposed copper-LMCT mechanism, supporting the mechanistic basis of this activation platform.</p>
|
Tiffany Q. Chen; P. Scott Pedersen; Nathan W. Dow; Remi Fayad; Cory E. Hauke; Michael C. Rosko; Evgeny O. Danilov; David C. Blakemore; Anne-Marie Dechert-Schmitt; Thomas Knauber; Felix N. Castellano; David W. C. MacMillan
|
Organic Synthesis and Reactions; Photochemistry (Org.); Homogeneous Catalysis; Photocatalysis; Redox Catalysis
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2021-04-20
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c757b29abda20e04f8e7b7/original/ligand-to-copper-charge-transfer-a-general-catalytic-approach-to-aromatic-decarboxylative-functionalization.pdf
|
635ec3a5cf6de9055c28a36e
|
10.26434/chemrxiv-2022-c1ctc-v2
|
XDM-Corrected Hybrid DFT with Numerical Atomic Orbitals Predicts Molecular Crystal Lattice Energies with Unprecedented Accuracy
|
Molecular crystals are important for many applications, including energetic materials, organic semi-conductors, and the development and commercialization of pharmaceuticals. The exchange-hole dipole moment (XDM) dispersion model has shown good performance in the calculation of relative and absolute lattice energies of molecular crystals, although it has traditionally been applied in combination with plane-wave/pseudopotential approaches. This has limited XDM to use with semilocal functional approximations, which suffer from delocalization error and poor quality conformational energies, and to systems with a few hundreds of atoms at most due to unfavorable scaling. In this work, we combine XDM with numerical atomic orbitals, which enable the efficient use of XDM-corrected hybrid functionals for molecular crystals. This improves the treatment of delocalization error and conformational energies, and makes the calculation scale linearly with system size. We test the new XDM-corrected functionals for their ability to predict the lattice energies of molecular crystals for the X23 set and 13 ice phases, the latter being a particularly stringent test. A composite approach using a XDM-corrected, 25% hybrid functional based on B86bPBE achieves a mean absolute error of 0.48 kcal/mol per molecule for the X23 set and 0.19 kcal/mol for the total lattice energies of the ice phases, compared to recent diffusion Monte-Carlo data. These results make the new XDM-corrected hybrids not only far more computationally efficient than previous XDM implementations, but also the most accurate density-functional methods for molecular crystal lattice energies to date.
|
Alastair Price; Alberto Otero-de-la-Roza; Erin Johnson
|
Theoretical and Computational Chemistry; Physical Chemistry; Computational Chemistry and Modeling; Theory - Computational; Physical and Chemical Properties
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2022-11-01
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/635ec3a5cf6de9055c28a36e/original/xdm-corrected-hybrid-dft-with-numerical-atomic-orbitals-predicts-molecular-crystal-lattice-energies-with-unprecedented-accuracy.pdf
|
677ca20e81d2151a0226e653
|
10.26434/chemrxiv-2025-qvt7v
|
Evaluating electrospun polycaprolactone fibers for blood-contacting applications
|
When the kidneys are injured, uremic toxins (UTXs) accumulate in the body, affecting other tissues and causing a loss of essential body functions. This study investigated the adsorption of blood plasma-laden uremic toxins on the surface of PCL fibers to assess their potential as an alternative to membrane dialysis materials. Using plasma containing 25 uremic toxins at a concentration similar to that found in end-stage kidney disease patients, we analyzed the adsorbed proteins and examined clot formation in normal and toxin-treated plasma in the presence of PCL fiberss. Our findings revealed that the presence of uremic toxins significantly increased the adsorption of proteins on PCL fiber meshes, without leading to increased clot formation. This suggests a lack of enzymatic activation despite the higher protein adsorption. Additionally, our study indicates that unmodified PCL surfaces have the potential to trigger a strong humoral immune response, underscoring the importance of understanding these interactions for the development of personalized treatment approaches for patients with kidney failure.
|
Muzammil Kuddushi; Aishwarya Pawar; Mehdi Ghaffari Sharaf; Larry Unsworth; Xuehua Zhang
|
Biological and Medicinal Chemistry
|
CC BY 4.0
|
CHEMRXIV
|
2025-01-08
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/677ca20e81d2151a0226e653/original/evaluating-electrospun-polycaprolactone-fibers-for-blood-contacting-applications.pdf
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62e1f5308e160780afd164b7
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10.26434/chemrxiv-2022-h3nhx
|
Electrocatalytic Ammonia Oxidation by a Low Coordinate Copper Complex
|
Molecular catalysts for ammonia oxidation to dinitrogen represent enabling components to utilize ammonia as a fuel and/or source of hydrogen. Ammonia oxidation requires not only the breaking of multiple strong N-H bonds, but also controlled N-N bond formation. We report a novel β-diketiminato copper complex [iPr2NNF6]Cu-NH3 ([Cu(I)]-NH3 (2)) as a robust electrocatalyst for NH3 oxidation in acetonitrile under homogeneous conditions. Complex 2 operates at a moderate overpotential (700 mV) with a TOFmax = 940 h-1 as determined from CV data in 1.3 M NH3 MeCN solvent. Prolonged (>5 h) controlled potential electrolysis (CPE) reveals the stability and robustness of the catalyst under electrocatalytic conditions. Detailed mechanistic investigations indicate that electrochemical oxidation of [Cu(I)]-NH3 forms {[Cu(II)]-NH3}+ (4) which undergoes deprotonation by excess NH3 to form reactive copper(II)-amide [Cu(II)]-NH2 (6) unstable towards N-N bond formation to give the dinuclear hydrazine complex [Cu(I)]2(mu-N2H4). Electrochemical studies reveal that the bisammine complex [Cu(I)](NH3)2 (7) forms at high ammonia concentration as part of the {[Cu(II)](NH3)2}+/[Cu(I)](NH3)2 redox couple that is electrocatalytically inactive. DFT analysis reveals a much higher thermodynamic barrier for deprotonation of {[Cu(II)](NH3)2}+ (8) by NH3 to give the four-coordinate copper(II) amide [Cu(II)](NH2)(NH3) (9) (dG = 31.7 kcal/mol) as compared to deprotonation of the three coordinate {[Cu(II)]-NH3}+ by NH3 to provide the reactive three coordinate parent amide [Cu(II)]-NH2 (dG = 18.1 kcal/mol) susceptible to N-N coupling to form [Cu(I)]2(mu-N2H4) (dG = -11.8 kcal/mol).
|
Md Estak Ahmed; Mahdi Raghibi Boroujeni; Pokhraj Ghosh; Christine Greene; Subrata Kundu; Jeffery Bertke; Timothy Warren
|
Inorganic Chemistry; Catalysis; Electrocatalysis; Homogeneous Catalysis
|
CC BY NC ND 4.0
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CHEMRXIV
|
2022-07-29
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/62e1f5308e160780afd164b7/original/electrocatalytic-ammonia-oxidation-by-a-low-coordinate-copper-complex.pdf
|
61eef0404b9500427a08e5e8
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10.26434/chemrxiv-2022-54qd3
|
Complex Loop Dynamics Underpin Activity, Specificity and Evolvability in the (βα)8 Barrel Enzymes of Histidine and Tryptophan Biosynthesis
|
Enzymes are conformationally dynamic, and their dynamical properties play an important role in regulating their specificity and evolvability. In this context, substantial attention has been paid to the role of ligand-gated conformational changes in enzyme catalysis; however, such studies have focused on tremendously proficient enzymes such as triosephosphate isomerase and orotidine 5’-monophosphate decarboxylase, where the rapid (μs timescale) motion of a single loop dominates the transition between catalytically inactive and active conformations. In contrast, the (βα)8-barrels of tryptophan and histidine biosynthesis, such as the specialist isomerase enzymes HisA and TrpF, and the bifunctional isomerase PriA, are decorated by multiple long loops that undergo conformational transitions on the ms (or slower) timescale. Studying the interdependent motions of multiple slow loops, and their role in catalysis, poses a significant computational challenge. This work combines conventional and enhanced molecular dynamics simulations with empirical valence bond simulations to provide rich detail of the conformational behavior of the catalytic loops in HisA, PriA and TrpF, and the role of their plasticity in facilitating bifunctionality in PriA and evolved HisA variants. In addition, we demonstrate that, similar to other enzymes activated by ligand-gated conformational changes, loops 3 and 4 of HisA and PriA act as gripper loops, facilitating the isomerization of the large bulky substrate ProFAR, albeit now on much slower timescales. This hints at convergent evolution on these different (βα)8-barrel scaffolds. Finally, our work highlights the potential of engineering loop dynamics as a powerful tool to artificially manipulate the diverse catalytic repertoire of TIM-barrel proteins.
|
Adrian Romero-Rivera; Marina Corbella; Antonietta Parracino; Wayne M. Patrick; Shina Caroline Lynn Kamerlin
|
Theoretical and Computational Chemistry; Biological and Medicinal Chemistry; Catalysis; Biochemistry; Bioinformatics and Computational Biology; Computational Chemistry and Modeling
|
CC BY 4.0
|
CHEMRXIV
|
2022-01-27
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/61eef0404b9500427a08e5e8/original/complex-loop-dynamics-underpin-activity-specificity-and-evolvability-in-the-8-barrel-enzymes-of-histidine-and-tryptophan-biosynthesis.pdf
|
60c741a5bdbb89774fa3839a
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10.26434/chemrxiv.8068307.v1
|
SuSMoST: Surface Science Modeling and Simulation Toolkit
|
We offer the scientific community the Surface Science Modelling and Simulation Toolkit (SuSMoST), which includes a number of utilities and implementations of statistical physics algorithms and models. With SuSMoST one is able to predict or explain the structure and thermodynamics properties of adsorption layers. SuSMoST automatically builds formal graph and tensor-network models from atomic description of adsorption complexes. So it can be routinely used for a wide class of adsorption systems. SuSMoST aids ab initio calculations of interactions between adsorbed species. In particular it generates surface samples considering symmetry of adsorption complexes. Using methods of various nature SuSMoST generates representative samples of adsorption layers and computes its thermodynamics quantities such as mean energy, coverage, density, heat capacity. From these data one can plot phase diagrams of adsorption systems, assess thermal stability of self-assembled structures, simulate thermal desorption spectra, etc.<br />
|
Sergey Akimenko; Galina Anisimova; Anastasiia Fadeeva; Vasilii Fefelov; Vitaly Gorbunov; Tatiana Kayumova; Myshlyavtsev Myshlyavtsev; Marta Myshlyavtseva; Pavel Stishenko
|
Computational Chemistry and Modeling; Self-Assembly; Statistical Mechanics
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2019-05-08
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c741a5bdbb89774fa3839a/original/su-s-mo-st-surface-science-modeling-and-simulation-toolkit.pdf
|
60c74554ee301c2a23c792d1
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10.26434/chemrxiv.10003157.v1
|
Enantioselective Olefin Hydrocyanation Without Cyanide
|
The enantioselective hydrocyanation of olefins represents a conceptually straightforward approach to prepare enantiomerically enriched nitriles. These, in turn, comprise or are intermediates in the synthesis of many pharmaceuticals and their synthetic derivatives. Herein, we report a cyanide-free dual Pd/CuH-catalyzed protocol for the asymmetric Markovnikov hydrocyanation of vinyl arenes and the anti-Markovnikov hydrocyanation of terminal olefins in which oxazoles function as nitrile equivalents. After an initial hydroarylation process, the oxazole substructure was deconstructed using a [4+2]/retro-[4+2] sequence to afford the enantioenriched nitrile product under mild reaction conditions.
|
Alexander Schuppe; Gustavo M. Borrajo-Calleja; Stephen L. Buchwald
|
Organic Synthesis and Reactions
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2019-10-23
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74554ee301c2a23c792d1/original/enantioselective-olefin-hydrocyanation-without-cyanide.pdf
|
64ca85194a3f7d0c0d7b4cea
|
10.26434/chemrxiv-2023-nb6g4
|
Efficient 2D to 0D Energy Transfer in HgTe Nanoplatelet-Quantum Dot Heterostructures through High-Speed Exciton Diffusion
|
Large area absorbers with localized defect emission are of interest for energy concentration via the antenna effect. Transfer between 2D and 0D quantum-confined structures is advantageous as it affords maximal lateral area antennas with continuously tunable emission. We report the quantum efficiency of energy transfer in in-situ grown HgTe nanoplatelet (NPL)/quantum dot (QD) heterostructures to be near unity (>85%), while energy transfer in separately synthesized and well separated solutions of HgTe NPLs to QDs only reaches 47±11% at considerably higher QD concentrations. Using Kinetic Monte Carlo simulations, we estimate an exciton diffusion constant of 1-10 cm2/s in HgTe NPLs, the same magnitude as 2D semiconductors. We also simulate in-solution energy transfer between NPLs and QDs, recovering an R^(-4) dependence, consistent with 2D-0D near-field energy transfer even in randomly distributed NPL/QD mixtures. This highlights the advantage of NPLs 2D morphology and the efficiency of NPL/QD heterostructures and mixtures for energy harvesting.
|
Stephanie Tenney; Lauren Tan; Xuanheng Tan; Mikayla Sonnleitner; Belle Coffey; Jillian Williams; Ricky Ronquillo; Timothy Atallah; Tasnim Ahmed; Justin Caram
|
Physical Chemistry; Nanoscience; Materials Chemistry
|
CC BY 4.0
|
CHEMRXIV
|
2023-08-03
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/64ca85194a3f7d0c0d7b4cea/original/efficient-2d-to-0d-energy-transfer-in-hg-te-nanoplatelet-quantum-dot-heterostructures-through-high-speed-exciton-diffusion.pdf
|
629c75506057b1651591faad
|
10.26434/chemrxiv-2022-ht2gb
|
Pulse dipolar EPR spectroscopy reveals buffer modulated cooperativity of metal templated protein dimerization
|
Self-assembly of protein monomers directed by metal ion coordination constitutes a promising strategy for designing supramolecular architectures complicated by the non-covalent interaction between monomers. Herein, two pulse dipolar electron paramagnetic resonance spectroscopy (PDS) techniques, double electron-electron resonance (DEER) and relaxation-induced dipolar modulation enhancement (RIDME), were simultaneously employed for studying the CuII-templated dimerization behavior of a model protein (Streptococcus sp. Group G, Protein G B1 domain) in both phosphate and Tris-HCl buffers. A cooperative binding model could simultaneously fit all data and demonstrate cooperativity of protein dimerization across α-helical double-histidine motifs in presence of Cu(II) is strongly buffer modulated, representing a platform for highly tunable buffer-switchable templated dimerization. Hence, PDS enriches the family of techniques for monitoring binding processes, supporting the development of novel strategies for bioengineering structures and stable architectures assembled by an initial metal-templated dimerization.
|
Maria Oranges; Joshua Wort; Miki Fukushima; Edoardo Fusco; Katrin Ackermann; Bela Bode
|
Physical Chemistry; Biological and Medicinal Chemistry; Inorganic Chemistry; Bioinorganic Chemistry; Biophysics; Spectroscopy (Physical Chem.)
|
CC BY 4.0
|
CHEMRXIV
|
2022-06-06
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/629c75506057b1651591faad/original/pulse-dipolar-epr-spectroscopy-reveals-buffer-modulated-cooperativity-of-metal-templated-protein-dimerization.pdf
|
67d6998e6dde43c908fbd66c
|
10.26434/chemrxiv-2025-v109w
|
Repairing Sequence-Induced Defects in Charge-Imbalanced Polyampholyte Hydrogels
|
Polyampholyte (PA) hydrogels, composed of cationic and anionic segments, are widely used in wearable device and brain-robot-interface. However, their structural stability is highly sensitive to anionic-to-cationic ratio, presenting challenges in achieving stability and robustness through trial-and-error experimental approaches. This work investigates sequence structures of PA hydrogels, revealing that deviations from ideal charge balance (anion fraction, f = 0.5) introduce sequence-induced defects, characterized by mismatched ionic segments, which significantly influences swelling behavior and mechanical performance. Such structure defects were effectively eliminated by introducing Fe3+, allowing PA gels to maintain stable mechanical properties across a broad f range (0.51-0.58), comparable to those of finely charge-balanced gels. FTIR and viscoelastic analyses suggest that Fe3+ coordination strengthens weak ionic bonds derived from sequence mismatches, enhancing the toughness of charge-imbalanced PA hydrogels. This work provides insights into the origin of internal defects and proposes a new approach for improving hydrogel stability through targeted defect mitigation.
|
Shanhao Feng; Shilei Zhu; Yang Qiao; Wenwen Yu; Fengbo Zhu; Ya Nan Ye; Qiang Zheng
|
Polymer Science; Coordination polymers; Hydrogels; Polymer chains
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2025-03-19
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/67d6998e6dde43c908fbd66c/original/repairing-sequence-induced-defects-in-charge-imbalanced-polyampholyte-hydrogels.pdf
|
670d954851558a15ef136e8c
|
10.26434/chemrxiv-2024-w3lxs
|
A ligand-assisted proximity effect allows for H2-driven copper hy-dride chemistry under mild conditions
|
A bifunctional copper(I)/N-heterocyclic carbene complex bearing a highly basic 2-iminopyridine subunit effects a variety of copper(I) hydride-based reductive transformations at low H2 pressure. The bifunctional catalyst allows for the first time to employ only catalytic amounts of alkoxide additive and is the copper(I) catalyst with the highest reactivity towards H2 re-ported so far. We can demonstrate that efficient alkyne semihydrogenations, conjugate reductions as well as 1,2-reductions of carbonyl compounds can be carried out at very low H2 pressure. The new protocol circumvents the need for previously required high-pressure equipment. At the same time, use of the new iminopyridine-based ligand allows for the tolerance of an unprecedented variety of functional groups in the realm of copper(I)-catalyzed hydrogenations. A possible working model featuring an iminopyridine-mediated proximity effect that coordinates the key alkoxide close to the reactive cop-per(I) center is proposed to account for the observed significant rise in reactivity. Mechanistic studies directed at support-ing this current working hypothesis are presented.
|
Mahadeb Gorai; Philipp Rotering; Jonas Franzen; Fabian Dielmann; Johannes Teichert
|
Organic Chemistry; Catalysis; Organometallic Chemistry; Organic Synthesis and Reactions; Homogeneous Catalysis; Ligand Design
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2024-10-16
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/670d954851558a15ef136e8c/original/a-ligand-assisted-proximity-effect-allows-for-h2-driven-copper-hy-dride-chemistry-under-mild-conditions.pdf
|
63657b7355a0817a11d2f3e2
|
10.26434/chemrxiv-2021-q0q9v-v2
|
Systematic study of triazolyl sterols for the development of new drugs against parasitic Neglected Tropical Diseases.
|
A series of thirty 1,2,3-triazolylsterols, inspired by azasterols with proven antiparasitic activity, were prepared by a stereocontrolled synthesis. Ten of these compounds constitute chimeras/hybrids of AZA and 1,2,3-triazolyl azasterols. The entire library was assayed against the kinetoplastid parasites Leishmania donovani, Trypanosoma cruzi, and Trypanosoma brucei, the causatives agents for visceral leishmaniasis, Chagas disease, and sleeping sickness, respectively. Most of the compounds were active at submicromolar/nanomolar concentrations with high selectivity index, when compared to their cytotoxicity against mammalian cells. Analysis of in silico physicochemical properties were conducted to rationalize the activities against the neglected tropical disease pathogens. The analogs with selective activity against L. donovani (E4, IC50 0.78 uM), T brucei (E1, IC50 0.12 uM) and T. cruzi (B1- IC50 0.33 uM), and the analogs with broad-spectrum antiparasitic activities against the three kinetoplastid parasites (B1 and B3), may be promising leads for further development as selective or broad-spectrum antiparasitic drugs.
|
Exequiel Porta; María Sol Ballari; Shane Wilkinson; Guoyi Ma; Babu Tekwani; Guillermo Labadie
|
Biological and Medicinal Chemistry; Drug Discovery and Drug Delivery Systems
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2022-11-07
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/63657b7355a0817a11d2f3e2/original/systematic-study-of-triazolyl-sterols-for-the-development-of-new-drugs-against-parasitic-neglected-tropical-diseases.pdf
|
64ef0655dd1a73847fd199c0
|
10.26434/chemrxiv-2023-wqmdv
|
Functional Polyester Synthesis from CO2, Butadiene and Epoxides
|
Carbon dioxide (CO2), as a renewable, abundant and inexpensive C1 feedstock, has long been recognized as an ideal comonomer to prepare sustainable materials. Contrast to the well-established alternating copolymerization of CO2 and epoxides, little success has been made on polymer synthesis via CO2/olefin copolymerization. Here we report an unprecedented strategy to synthesize bifunctional polyesters from CO2, butadiene, and epoxides via a metastable lactone intermediate, 3-ethylidene-6-vinyltetrahydro-2H-pyran-2-one (EVP). The obtained polyesters with tunable EVP content (39-93 mol%) show good thermal stability, and can conveniently undergo chemical degradation. Mechanistic studies revealed that the in situ formation of dimer EVP circumvented the electronic effect of conjugated ester and enhanced the steric hindrance, promoting the desired ring-opening reaction. This method extends the potential to access functional CO2-based polymers beyond the conventional polycarbonates obtained from CO2 and epoxides.
|
Yajun Zhao; Xiaohui Zhang; Zhuang Li; Shan Tang
|
Polymer Science
|
CC BY NC 4.0
|
CHEMRXIV
|
2023-08-31
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/64ef0655dd1a73847fd199c0/original/functional-polyester-synthesis-from-co2-butadiene-and-epoxides.pdf
|
60c73d0d469df4b750f42662
|
10.26434/chemrxiv.5356327.v1
|
Improving the Mechanical Durability of Superhydrophobic Coating by Deposition on to a Mesh Structure
|
<p>Superhydrophobic surfaces (SHSs) require a
combination of a rough nano- or microscale structured surface topography and a
low surface energy. However, its superydrophobicity is easily lost, even under
relatively mild mechanical abrasion, when the surface is mechanically weak.
Here, we develop a method that significantly increases the mechanical
durability of a superhydrophobic surface, by introducing a mesh layer beneath
the superhydrophobic layer. The hardness, abrasion distance, flexibility and
water-jet impact resistance all increase for the commercially available
Ultra-ever Dry superhydrophobic coating. This is attributed to the increased
mechanical durability offered by the mesh, whose construction not only
increases the porosity of the SHS coating but acts as a third, larger
structure, so that the superhydrophobic layer is now composed of a three-level
hierarchical structure: the mesh, micropillars and nanoparticles.</p>
|
Weihua Hu; De-Quan Yang; Edward Sacher
|
Coating Materials; Nanostructured Materials - Nanoscience
|
CC BY NC 4.0
|
CHEMRXIV
|
2017-08-31
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c73d0d469df4b750f42662/original/improving-the-mechanical-durability-of-superhydrophobic-coating-by-deposition-on-to-a-mesh-structure.pdf
|
60c75686567dfe622cec64e4
|
10.26434/chemrxiv.14251649.v1
|
Synthesis of Multi-Protein Complexes through Charge-Directed Sequential Activation of Tyrosine Residues
|
Site-selective protein-protein coupling has long been a goal of chemical biology research. In recent years, that goal has been realized to varying degrees through a number of techniques, including the use of tyrosinase-based coupling strategies. Early publications utilizing tyrosinase from <i>Agaricus bisporus</i> showed the potential to convert tyrosine residues into <i>ortho</i>-quinone functional groups, but this enzyme is challenging to produce recombinantly and suffers from some limitations in substrate scope. Initial screens of several tyrosinase candidates revealed that the tyrosinase from <i>Bacillus megaterium</i> (megaTYR) as an enzyme that possesses a broad substrate tolerance. We use the expanded substrate preference as a starting point for protein design experiments and show that single point mutants of megaTYR are capable of activating tyrosine residues in various sequence contexts. We leverage this new tool to enable the construction of protein trimers via a charge-directed sequential activation of tyrosine residues (CDSAT).
|
Casey S. Mogilevsky; Marco Lobba; Daniel D. Brauer; Alan Marmelstein; Johnathan Maza; Jamie M. Gleason; Jennifer A. Doudna; Matthew Francis
|
Aggregates and Assemblies; Biocompatible Materials; Biological Materials; Bioengineering and Biotechnology; Chemical Biology; Drug Discovery and Drug Delivery Systems; Biocatalysis
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2021-03-23
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c75686567dfe622cec64e4/original/synthesis-of-multi-protein-complexes-through-charge-directed-sequential-activation-of-tyrosine-residues.pdf
|
652c199545aaa5fdbb124118
|
10.26434/chemrxiv-2023-h2nph
|
Flash-within-flash synthesis of gram-scale solid-state materials
|
Sustainable manufacturing that prioritizes energy efficiency, minimal water use, scalability, and the ability to generate diverse materials is essential to advance inorganic materials production while maintaining environmental consciousness. However, current manufacturing practices are unable to meet these requirements. Here, we describe a new flash-within-flash Joule heating (FWF)—a non-equilibrium, ultrafast heat conduction method—to prepare 13 transition metal dichalcogenides (TMD) and 9 non-TMD materials, each in under 5 seconds while in ambient conditions. FWF achieves enormous advantages in facile gram scalability and in sustainable manufacturing criteria when compared to other synthesis methods. Also, FWF allows the production of phase-selective and single-crystalline bulk powders, a phenomenon rarely observed by any other synthesis method. Furthermore, FWF-made MoSe2 outperformed commercially available MoSe2 in tribology, showcasing the quality of FWF-made materials. The capability for atom substitution and doping further highlights the versatility of FWF as a general bulk inorganic materials synthesis protocol.
|
Chi Choi; Jaeho Shin; Lucas Eddy; Victoria Granja; Kevin Wyss; Bárbara Damasceno; Hua Gao; Guanhui Gao; Yufeng Zhao; C. Fred Higgs, III; Yimo Han; James Tour
|
Inorganic Chemistry; Solid State Chemistry
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2023-10-16
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/652c199545aaa5fdbb124118/original/flash-within-flash-synthesis-of-gram-scale-solid-state-materials.pdf
|
6261042211b146bbdb2ac47b
|
10.26434/chemrxiv-2022-gcrjg
|
Quick and Efficient Quantitative Predictions of Androgen Receptor Binding Affinity for Screening Endocrine Disruptor Chemicals Using 2D-QSAR and Chemical Read-Across
|
Endocrine Disruptor Chemicals are synthetic or natural molecules in the environment that promote adverse modifications of endogenous hormone regulation in humans and/or in animals. In the present research, we have applied two-dimensional quantitative structure-activity relationship (2D-QSAR) modeling to analyze the structural features of these chemicals responsible for binding to the androgen receptors (logRBA) in rats. We have collected the receptor binding data from the EDKB database (https://www.fda.gov/science-research/endocrine-disruptor-knowledge-base/accessing-edkb-database) and then employed the DTC-QSAR tool, available from https://dtclab.webs.com/software-tools, for dataset division, feature selection, and model development. The final partial least squares was evaluated using various stringent validation criteria. From the model, we interpreted that hydrophobicity, steroidal nucleus, bulkiness and a hyrdrogen bond donor at an appropriate position contribute to the receptor binding affinity, while presence of electron rich features like aromaticity and polar groups decrease the receptor binding affinity. Additionally we have also performed chemical Read-Across predictions using Read-Across-v3.1 available from https://sites.google.com/jadavpuruniversity.in/dtc-lab-software/home, and the results for the external validation metrics were found to be better than the QSAR-derived predictions. To explore the essential features responsible for the receptor binding, pharmacophore mapping, molecular docking along with molecular dynamics simulation were also performed, and the results are in accordance with the QSAR findings.
|
Arkaprava Banerjee; Priyanka De; Vinay Kumar; Supratik Kar; Kunal Roy
|
Theoretical and Computational Chemistry; Computational Chemistry and Modeling; Chemoinformatics - Computational Chemistry
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2022-04-21
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6261042211b146bbdb2ac47b/original/quick-and-efficient-quantitative-predictions-of-androgen-receptor-binding-affinity-for-screening-endocrine-disruptor-chemicals-using-2d-qsar-and-chemical-read-across.pdf
|
60c7548d469df463aaf44f7a
|
10.26434/chemrxiv.13681426.v1
|
A Mechanistic Analysis of Trimethylanilinium Salt Degradation: Implications for Methylation and Cross-coupling Applications
|
<i>N,N,N</i>-trimethylanilinium
salts are known to display dual reactivity through both the aryl group and the <i>N</i>-methyl groups. These salts have thus
been widely applied in cross-coupling, aryl etherification, fluorine
radiolabelling, phase-transfer catalysis, supramolecular recognition, polymer
design, and (more recently) methylation. However, their application as electrophilic
methylating reagents remains somewhat underexplored, and an understanding of
their arylation versus methylation reactivities is lacking. This study presents
a mechanistic degradation analysis of <i>N,N,N</i>-trimethylanilinium
salts and highlights the implications for synthetic applications of this
important class of salts. Kinetic degradation studies, in both solid state and
solution phases, have delivered insights into the physical and chemical
parameters affecting anilinium salt stability. <sup>1</sup>H NMR kinetic
analysis of salt degradation has evidenced thermal degradation to methyl iodide
and the parent aniline, consistent with a closed-shell S<sub>N</sub>2-centred degradative
pathway, and methyl iodide being the key reactive species in applied
methylation procedures. Furthermore, the effect of halide and non-nucleophilic
counterions on salt degradation has been investigated, along with deuterium
isotope and solvent effects. Finally, new mechanistic insights have enabled the
investigation of the use of trimethylanilinium salts in O-methylation and in
improved cross-coupling strategies.
|
Jack B. Washington; Michele Assante; Chunhui Yan; David McKinney; Vanessa Juba; Andrew Leach; Sharon E. Baillie; Marc Reid
|
Organic Compounds and Functional Groups; Organic Synthesis and Reactions; Physical Organic Chemistry; Process Chemistry; Computational Chemistry and Modeling; Chemical Kinetics; Physical and Chemical Properties
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2021-02-02
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c7548d469df463aaf44f7a/original/a-mechanistic-analysis-of-trimethylanilinium-salt-degradation-implications-for-methylation-and-cross-coupling-applications.pdf
|
60c74d2eee301c89d4c7a200
|
10.26434/chemrxiv.12595340.v1
|
Electrochemically Driven Desaturation of Carbonyl Compounds
|
<p> Electrochemical techniques have long been heralded for their innate sustainability as efficient methods for
achieving redox reactions. Carbonyl desaturation, as a fundamental organic oxidation, is an oft-employed transformation to
unlock adjacent reactivity. To date, the most reliable methods
for achieving it have relied on transition metals (Pd/Cu) or stoichiometric reagents based on I, Br, Se, or S. Herein we report an
operationally simple pathway to such structures from enol
silanes and phosphates using electrons as the primary reagent.
This electrochemically driven desaturation exhibits a broad
scope across an array of carbonyl derivatives, is easily scalable
(1-100g), and can be predictably implemented into synthetic
pathways using experimentally or computationally derived
NMR shifts. Mechanistic interrogation suggests a radical-based
reaction pathway. <br /></p>
|
Samer Gnaim; Yusuke Takahira; Henrik Wilke; Zhen Yao; Jinjun Li; Dominique Delbrayelle; Pierre-Georges Echeverria; Julien Vantourout; Phil Baran
|
Organic Synthesis and Reactions; Electrochemistry
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2020-07-02
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74d2eee301c89d4c7a200/original/electrochemically-driven-desaturation-of-carbonyl-compounds.pdf
|
60c73fdf9abda209c4f8bb77
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10.26434/chemrxiv.7528946.v1
|
Sulfonamides Are an Overlooked Class of Electron Donors in Luminogenic Luciferins and Fluorescent Dyes
|
Many fluorophores, and all bright light-emitting
substrates for firefly luciferase, contain hydroxyl or amine electron donors.
Here we show that sulfonamides can serve as replacements for these canonical
groups. Unlike “caged” carboxamides, sulfonamide analogues enable
bioluminescence, and sulfonamidyl luciferins, coumarins, rhodols, and
rhodamines are fluorescent in water. Sulfonamide donors thus have previously unappreciated
potential to expand the functional repertoire of luminescent molecules.
|
Deepak K. Sharma; Spencer T. Adams; Kate L. Liebmann; Adam Choi; Stephen Miller
|
Bioorganic Chemistry; Organic Compounds and Functional Groups; Organic Synthesis and Reactions; Photochemistry (Org.); Imaging; Biochemistry; Chemical Biology
|
CC BY NC ND 4.0
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CHEMRXIV
|
2018-12-31
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c73fdf9abda209c4f8bb77/original/sulfonamides-are-an-overlooked-class-of-electron-donors-in-luminogenic-luciferins-and-fluorescent-dyes.pdf
|
60c742baee301c548cc78ed7
|
10.26434/chemrxiv.8223998.v1
|
The Calculation of the Infrared and Terahertz Spectrum of Sodium Peroxodisulfate.
|
A number of DFT programs with various combinations of pseudo-potentials and van der Waals’ dispersive corrections have been used to optimize the structure of sodium peroxodisulfate, Na<sub>2</sub>(SO<sub>4</sub>)<sub>2</sub>, and to calculate the infra-red and terahertz absorption spectrum of the powdered crystal. Comparison of the results from the different methods highlights the problems of calculating the absorption spectrum reliably. In particular the low frequency phonon modes are especially sensitive to the choice of grids to represent the wavefunction or the charge distribution, k-point integration grid and the energy cutoff. A comparison is made between the Maxwell-Garnett (MG) and Bruggeman effective medium methods used to account for the effect of crystal shape on the predicted spectrum. Possible scattering of light by air inclusions in the sample and by larger particles of Na<sub>2</sub>(SO<sub>4</sub>)<sub>2</sub> is also considered using the Mie method. The results of the calculations are compared with experimental measurements of the transmission and attenuated total reflection spectra
<br />
|
John Kendrick; Andrew Burnett
|
Computational Chemistry and Modeling; Theory - Computational; Optics; Physical and Chemical Properties; Spectroscopy (Physical Chem.)
|
CC BY NC ND 4.0
|
CHEMRXIV
|
1970-01-01
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c742baee301c548cc78ed7/original/the-calculation-of-the-infrared-and-terahertz-spectrum-of-sodium-peroxodisulfate.pdf
|
66cc9e5e20ac769e5fe58065
|
10.26434/chemrxiv-2024-vfkz0
|
Polyethersulfones upcycling to luminescent materials by aminolysis
|
Upcycling of polyethersulfone (PES), a high-performance polymer based on an aromatic-rich aryl-ether-based backbone, can advantageously yield both starting Bisphenol S (BPS) comonomer and valuable OLED derivatives, providing complete atom valorisation strategy for PES waste. Deprotonated selected amines proved particularly efficient at depolymerizing PES at moderate temperatures (~ 120 °C). The recycled monomer yields validate the back-to-monomer chemical recycling method for industrial compliance. The OLED derivatives afforded by the same simple process can easily be isolated and promote an innovative upcycling strategy using polymer-to-valuable chemicals, a very relevant approach to help tackle the ever-growing plastic waste remediation.
|
Johan Liotier; Leila Issoufou Alfari; Benoît Mahler; Thomas Niehaus; Christophe Dujardin; Simon Guelen; Vincent Schanen; Véronique Dufaud; Jean RAYNAUD; Vincent Monteil
|
Polymer Science
|
CC BY NC 4.0
|
CHEMRXIV
|
2024-08-27
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/66cc9e5e20ac769e5fe58065/original/polyethersulfones-upcycling-to-luminescent-materials-by-aminolysis.pdf
|
658e86b566c1381729443baa
|
10.26434/chemrxiv-2023-28q5w
|
Detection of a Kinetically Competent Compound-I Intermediate in the Vancomycin Biosynthetic Enzyme OxyB
|
Cytochrome P450 enzymes are abundantly encoded in microbial genomes. Their reactions have two general outcomes, one involving oxygen insertion via a canonical ‘oxygen rebound’ mechanism and a second that diverts from this pathway and leads to a wide array of products, notably intramolecular oxidative crosslinks. The antibiotic of-last-resort vancomycin contains three such crosslinks, which are crucial for biological activity and are installed by the P450 enzymes OxyB, OxyA, and OxyC. The mechanisms of these enzymes have remained elusive in part because of the difficulty in spectroscopically capturing transient intermediates. Using stopped-flow UV/Visible absorption and rapid freeze-quench electron paramagnetic resonance spectroscopies, we show that OxyB generates the highly reactive compound-I intermediate, which can react with a model vancomycin peptide substrate in a kinetically competent fashion to generate product. Our results have implications for the mechanism of OxyB and are in line with the notion that oxygen rebound and oxidative crosslinks share early steps in their catalytic cycles.
|
Andy K. L. Nguy; Ryan J. Martinie; Amanda Cai; Mohammad R. Seyedsayamdost
|
Biological and Medicinal Chemistry; Biochemistry
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2023-12-29
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/658e86b566c1381729443baa/original/detection-of-a-kinetically-competent-compound-i-intermediate-in-the-vancomycin-biosynthetic-enzyme-oxy-b.pdf
|
64831e0c4f8b1884b70f34ad
|
10.26434/chemrxiv-2023-h0qrq
|
Crystal Structure Prediction of Energetic Materials
|
The synthesis and experimental testing of energetic materials can be hazardous, but their many industrial and military applications necessitate their constant research and development. We evaluate computational methods for predicting the crystal structures of energetic molecular organic crystals from their molecular structure as a first step in computationally evaluating materials, which could guide experimental work. Crystal structure prediction (CSP) is evaluated on a test set of ten energetic materials with known crystal structures, initially using a rigid-molecule, anisotropic atom-atom force field approach, followed by re-optimization of predicted crystal structures using dispersion-corrected solid state density functional theory (DFT). CSP using the force field was found to provide good results for some molecules, whose known crystal structures are reproduced by one of the lowest energy predictions, but are more variable than for other small organic molecules. Re-optimization of predicted crystal structures using solid state DFT leads to reliable predictions, demonstrating CSP as a approach that can be applied in the area of energetic materials discovery and development.
|
Joseph E. Arnold; Graeme M. Day
|
Theoretical and Computational Chemistry; Computational Chemistry and Modeling; Materials Chemistry
|
CC BY 4.0
|
CHEMRXIV
|
2023-06-13
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/64831e0c4f8b1884b70f34ad/original/crystal-structure-prediction-of-energetic-materials.pdf
|
659d6cf366c138172910be90
|
10.26434/chemrxiv-2024-3x777
|
Navigating Antibacterial Frontiers: Landscape Analysis of Antibiotics, Resistance Mechanisms and Emerging Therapeutic Strategies
|
Developing effective antibacterial solutions has become paramount in maintaining global health in this era of increasing bacterial threats and rampant antibiotic resistance. Traditional antibiotics have played a significant role in combating bacterial infections throughout history. However, the emergence of novel resistant strains necessitates constant innovation in antibacterial research. We have analyzed the data on antibacterials from the CAS Content CollectionTM, the largest human-curated collection of published scientific knowledge, proven valuable for quantitative analysis of global scientific knowledge. Our analysis focuses on mining the CAS Content Collection data for recent publications (since 2012). This article aims to explore the intricate landscape of antibacterial research while reviewing the advancement from traditional antibiotics to novel and emerging antibacterial strategies. By delving into the resistance mechanisms, this paper highlights the need to find alternate strategies to address the growing concern.
|
Krittika Ralhan; Kavita Iyer; Leilani Lotti Diaz; Robert Bird; Qiongqiong Zhou
|
Biological and Medicinal Chemistry; Drug Discovery and Drug Delivery Systems
|
CC BY 4.0
|
CHEMRXIV
|
2024-01-10
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/659d6cf366c138172910be90/original/navigating-antibacterial-frontiers-landscape-analysis-of-antibiotics-resistance-mechanisms-and-emerging-therapeutic-strategies.pdf
|
60c73d97469df448fcf42762
|
10.26434/chemrxiv.6015611.v1
|
Hydration Free Energies of Organic Molecules in the FreeSolv Database Calculated with Polarized Atom In Molecules Atomic Charges and the GAFF Force Field.
|
<div>Computer simulations of bio-molecular systems often use force fields, which are combinations of simple empirical atom-based functions to describe the molecular interactions. Even though polarizable force fields give a more detailed description of intermolecular interactions, nonpolarizable force fields, developed several decades ago, are often still preferred because of their reduced computation cost. Electrostatic interactions play a major role in bio-molecular systems and are therein described by atomic point charges.</div><div>In this work, we address the performance of different atomic charges to reproduce experimental hydration free energies in the FreeSolv database in combination with the GAFF force field. Atomic charges were calculated by two atoms-in-molecules approaches, Hirshfeld-I and Minimal Basis Iterative Stockholder (MBIS). To account for polarization effects, the charges were derived from the solute's electron density computed with an implicit solvent model and the energy required to polarize the solute was added to the free energy cycle. The calculated hydration free energies were analyzed with an error model, revealing systematic errors associated with specific functional groups or chemical elements. The best agreement with the experimental data is observed for the MBIS atomic charge method, including the solvent polarization, with a root mean square error of 2.0 kcal mol<sup>-1</sup> for the 613 organic molecules studied. The largest deviation was observed for phosphor-containing molecules and the molecules with amide, ester and amine functional groups.</div>
|
Maximiliano Riquelme; Alejandro Lara; David L. Mobley; Toon Vestraelen; Adelio R Matamala; Esteban Vöhringer-Martinez
|
Computational Chemistry and Modeling
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2018-03-22
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c73d97469df448fcf42762/original/hydration-free-energies-of-organic-molecules-in-the-free-solv-database-calculated-with-polarized-atom-in-molecules-atomic-charges-and-the-gaff-force-field.pdf
|
63f940b732cd591f126ed34a
|
10.26434/chemrxiv-2023-fjk22-v2
|
Revisiting a Flotation Cell Benchmark
|
Developing a flotation benchmark to compare any flotation system has been challenging due to the great variation which exists in flotation cell types, geometry, and internal hydrodynamics. Parkes et al (2022) focused on the product flux passing through the upper surface as a Performance Measure, interpreting a batch mechanical cell as a steady-state plug flow device, equivalent to infinite steady-state tanks in series. Recent work revealed a conundrum that arises out of the tanks in series analysis when applied to a system of fixed volume. This Technical Note resolves the issue, providing a much stronger and clearer framework for the flotation benchmark.
|
Sian Parkes; Peipei Wang; Kevin P. Galvin
|
Chemical Engineering and Industrial Chemistry; Natural Resource Recovery; Reaction Engineering
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2023-02-27
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/63f940b732cd591f126ed34a/original/revisiting-a-flotation-cell-benchmark.pdf
|
670d679d12ff75c3a16b3977
|
10.26434/chemrxiv-2024-r4fj6
|
Pressure-Dependent Kinetic Analysis of the N2H3 Potential Energy Surface
|
Pressure-dependent reactions on the N2H3 potential energy surface (PES) are studied at the CCSDT(Q)/aug-cc-pVTZ//B2PLYPD3/aug-cc-pVTZ level of theory. This work extends the N2H3 PES relative to previous literature studies by adding another isomer, NH3N, and additional bimolecular channels adjacent to the new isomer, NNH + H2, and H2NN + H. Theoretical predictions are made for the rate coefficients of all path and well-skipping pressure-dependent reactions. The theoretical analyses employ a combination of ab-initio transition state theory and master equation simulations. Pressure-dependent rate coefficients are computed for all reactions in the network. The dominant products of NH2+NH(T) recombination are N2H2+H, and at high pressures and low temperatures N2H3 formation becomes important. Collisions of H2NN + H on this surface yield mainly N2H2 +H as well. Important secondary reactions are H2NN+ H <=> NNH + H2 at high temperatures and all examined pressures and H2NN + H <=> N2H3 at low temperatures and high pressures. None of these three reactions were considered by previous NH3 oxidation models with pressure-dependent rate coefficients. The rate coefficients obtained here should be useful in modeling ammonia, hydrazine, and hydrazine derivatives in various combustion environments.
|
Michal Keslin; Kfir Kaplan; Alon Grinberg Dana
|
Theoretical and Computational Chemistry; Physical Chemistry; Computational Chemistry and Modeling; Chemical Kinetics; Quantum Mechanics
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2024-10-16
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/670d679d12ff75c3a16b3977/original/pressure-dependent-kinetic-analysis-of-the-n2h3-potential-energy-surface.pdf
|
6787f942fa469535b92cbd67
|
10.26434/chemrxiv-2025-d0b12
|
Scalable Main Group Mechanocatalytic CO2 Valorisation to Cyclocarbonate Species
|
Over the past two decades, main group elements have gained attention as promising substitutes for precious metals in catalytic processes. Additionally, mechanochemistry is emerging as a field with the potential to promote catalytic reactions under mild conditions. Herein, we report a scalable, main-group mechanocatalytic synthesis of cyclic carbonates from both solid and liquid epoxides, using CO₂ as a renewable feedstock under mild conditions with a gallium aminotrisphenolate catalyst. Unlike solution-based methods, which generally require high temperatures and/or high CO₂ pressures, this mechanocatalytic process operates at just 1 bar and room temperature. The developed mechanochemical method affords the targetted compounds in high yields, while also enabling efficient transformation of multi-terminal epoxides and avoiding the conversion losses typically observed in solution. Furthermore, this scalable method outperforms solution-based approaches across all green metrics, setting a new benchmark for environmentally friendly synthesis.
|
Javier F. Reynes; Lucía Álvarez-Miguel; Frederik Winkelmann; Michael Felderhoff; Marta E G. Mosquera; Christopher J. Whiteoak; Felipe Garcia
|
Organic Chemistry; Inorganic Chemistry; Catalysis; Organic Synthesis and Reactions; Main Group Chemistry (Inorg.); Solid State Chemistry
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2025-01-21
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6787f942fa469535b92cbd67/original/scalable-main-group-mechanocatalytic-co2-valorisation-to-cyclocarbonate-species.pdf
|
60c759aa567dfe6399ec6aa9
|
10.26434/chemrxiv.14720883.v1
|
Targetable Conformationally Restricted Cyanines Enable Photon-Count Limited Applications
|
Cyanine dyes are exceptionally useful probes for a range of fluorescence-based applications. We recently demonstrated that appending a ring system to the pentamethine cyanine ring system improves the quantum yield and extends the fluorescence lifetime. Here, we report an optimized synthesis of persulfonated variants that enable efficient labeling of nucleic acids and proteins. We demonstrate that a bifunctional sulfonated tertiary amide significantly improves the optical properties of the resulting bioconjugates. These new conformationally restricted cyanines are compared to parent species in a range of contexts including their use on a DNA-nano-antenna, in single-molecule Förster resonance energy transfer (FRET) applications, far-red fluorescence lifetime imaging microscopy (FLIM), and single-molecule localization microscopy. These efforts define contexts in which eliminating cyanine isomerization provides meaningful benefits to imaging performance.
|
Patrick Eiring; Ryan McLaughlin; Siddharth Matikonda; HAN ZHONGYING; Lennart Grabenhorst; Dominic Helmerich; Mara Meub; Gerti Beliu; Michael Luciano; Venu Bandi; Niels Zijlstra; Zhen-Dan Shi; Rolf Swenson; Philip Tinnefeld; Viktorija Glembockyte; Thorben Cordes; Markus Sauer; Martin Schnermann
|
Organic Synthesis and Reactions
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2021-06-03
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c759aa567dfe6399ec6aa9/original/targetable-conformationally-restricted-cyanines-enable-photon-count-limited-applications.pdf
|
60c74f6d702a9b2aea18bb8f
|
10.26434/chemrxiv.12901346.v1
|
On the Variability of Ligand pKa during Homogeneously Catalyzed Aqueous Methanol Dehydrogenation
|
<p>Using DFT based molecular dynamics simulations</p><p>incorporating explicit water solvent, we elucidate the varying behaviour of the ligand pKa of a molecular catalyst for methanol dehydrogenation, using the Ru(PNP) catalytic system</p><p>as a case study. The pKa of the amido ligand moiety in this catalytic system is highly sensitive to the species adsorbed on the metal</p><p>center, resulting in a substantial variation of the ligand pKa along the catalytic cycle. Since the ligand pKa is an important characteristic that determines the exact role of the ligand during aqueous methanol dehydrogenation, this characteristic has important implications on metal ligand cooperative pathways.</p>
|
Nitish Govindarajan; Hugo Beks; E.J. Meijer
|
Homogeneous Catalysis
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2020-09-01
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74f6d702a9b2aea18bb8f/original/on-the-variability-of-ligand-p-ka-during-homogeneously-catalyzed-aqueous-methanol-dehydrogenation.pdf
|
6688078501103d79c51d18ac
|
10.26434/chemrxiv-2024-d4cjt
|
SYNTHESIS, CHARACTRIZATION AND ANTIBACTERIAL ACTIVITY OF SCHIFF BASES DERIVED FROM PHENYL HYDRAZINE DERIVATIVES AND THEIR Cu (II) and Zn (II) COMPLEXES
|
Phenyl hydrazine Schiff bases have received a lot of attention recently because of their biological importance and potential medical applications. These compounds are of particular interest because they have a variety of beneficial properties, including antibacterial, anticancer, antimalarial, antiinflammatory, antinociceptive, antitubercular, anthelmintic, antidiabetic, and antiepileptic. In this research, Phenyl hydrazine derivatives of Schiff base ligands namely ((E)-2-benzylidene-1-phenylhydrazine, (E)-2-(4-nitrobenzylidene) phenyl hydrazine, 2,2'-((1E, 1’E)-hydrazine-1,2-diylidenebis (methanylylidene)) diphenol and (E)-2-(2-hydroxybenzylidene)-1-phenylhydrazine) and their copper(II) and zinc(II) complexes were synthesized and described. The synthesized ligands, were characterized by varieties of techniques including Fourier transform Infrared, UV-Visible and NMR (13C-NMR and 1H-NMR) spectroscopies. The complexes were synthesized via the reactions of ligands with the corresponding metal acetates in a medium of methanol which were then characterized by UV –Vis and IR spectroscopies. In-vitro antibacterial activity of the ligand and metal complexes were carried out against three bacteria species E. coli s, Staphylococcus aureus, and Pseudomonas aeruginosa by disc diffusion method. The antibacterial activity shows that the copper (II) complex (TCO8) the highest activity against bacteria than the Zn (II) metal complexes and the free ligand. The minimum inhibitory concentration of the Cu(II) complex (TCO8) demonstrated excellent antibacterial activity varies from 5-10 µl/ml, against S. auras, E. Coli, P. aeruginosa with inhibition zone of 21mm, 16mm, 11mm respectively, using ciprofloxacin as a standard drug.
|
Henok Abebe; Tesfaye Lamma; Adelew Filkale; Dagne Kure
|
Organic Chemistry; Inorganic Chemistry; Bioinorganic Chemistry; Coordination Chemistry (Inorg.)
|
CC BY NC 4.0
|
CHEMRXIV
|
2024-07-08
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6688078501103d79c51d18ac/original/synthesis-charactrization-and-antibacterial-activity-of-schiff-bases-derived-from-phenyl-hydrazine-derivatives-and-their-cu-ii-and-zn-ii-complexes.pdf
|
6717741c83f22e4214c93722
|
10.26434/chemrxiv-2024-2vbvs
|
Harnessing Carbene Reactivity of [1.1.1]Propellane for [2,3]-Sigmatropic Rearrangement: Application and Mechanistic Studies
|
[1.1.1]Propellane is a highly strained smallest tricyclic hydrocarbon, and its reactivity is primarily engrossed by addition reactions across the strained C-C bond, leading to the formation of bicyclo[1.1.1]pentane derivatives. Herein, we present an unprecedented [2,3]-sigmatropic rearrangement that uses [1.1.1]propellane as a carbene precursor to rapidly access allenylated or allylated methylenecyclobutanes. The reaction is highly efficient and scalable, works well under mild conditions, and can tolerate remarkable functional groups on propargyl and allyl sulfides/selenides. Another significant achievement of this approach is the utility of the obtained products in synthesizing substituted bicyclo[2.1.1]hexanes, potential bioisosteres of ortho and meta-substituted benzenes, by developing a novel photocatalyzed radical cascade cyclization. Density functional theory calculations have suggested that the mechanism of this reaction proceeds via a Cu(I)-assisted five-membered envelope transition state to give the [2,3]-rearrangement product.
|
Suparnak Midya; Aksar Ali; Durga Prasad Hari
|
Organic Chemistry; Catalysis; Organic Synthesis and Reactions; Homogeneous Catalysis; Photocatalysis
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2024-10-24
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6717741c83f22e4214c93722/original/harnessing-carbene-reactivity-of-1-1-1-propellane-for-2-3-sigmatropic-rearrangement-application-and-mechanistic-studies.pdf
|
670a711a51558a15efdb4be0
|
10.26434/chemrxiv-2024-wtbqh
|
Development of FT-IR and FT-NIR methods for analysis of moisture and sugars in Jaggery
|
Jaggery is a natural sweetener obtained from sugarcane, palm or sweet sorghum. It is consumed in almost all sections of the society in India. Number of R&D efforts have been made to understand the physio-chemical properties via analytical method developments and functional properties of jaggery. However, majority of jaggery analysis is still being carried out by employing conventional methods which are laborious and time consuming. In this preprint, we report the, FT-IR and FT-NIR methods for analysis of moisture content and sugar contents in jaggery.
|
Anusree L; Raksha U; Nanishankar Harohally
|
Agriculture and Food Chemistry
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2024-10-22
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/670a711a51558a15efdb4be0/original/development-of-ft-ir-and-ft-nir-methods-for-analysis-of-moisture-and-sugars-in-jaggery.pdf
|
60c745bb567dfe10feec44df
|
10.26434/chemrxiv.9272684.v3
|
Copper Reactivity Can be Tuned to Catalyse the Stereoselective Synthesis of 2-Deoxy Glycosides from Glycals
|
<p><a></a>We demonstrate that tuning the reactivity of Cu by the choice of oxidation state and counterion leads to the activation of both “armed” and “disarmed” type glycals towards direct glycosylation leading to the a-stereoselective synthesis of deoxyglycosides in good to excellent yields. Mechanistic studies show that CuI is essential for effective catalysis and stereocontrol and that the reaction proceeds through dual activation of both the enol ether as well as the OH nucleophile.</p>
|
Carlos Palo-Nieto; Abhijit Sau; Robin Jeanneret; Pierre-Adrien Payard; Maristela Braga Martins-Teixeira; Ivone Carvalho; Laurence Grimaud; M. Carmen Galan
|
Organic Synthesis and Reactions; Homogeneous Catalysis; Catalysis
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2019-10-16
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c745bb567dfe10feec44df/original/copper-reactivity-can-be-tuned-to-catalyse-the-stereoselective-synthesis-of-2-deoxy-glycosides-from-glycals.pdf
|
6463c0bda32ceeff2dc08a2d
|
10.26434/chemrxiv-2023-q2gdd
|
Frustrated Ion Pair-Enabled Cross-Electrophile Coupling of Unactivated Alkyl Electrophiles
|
Cross-electrophile coupling reactions have evolved into a major strategy for rapidly assembling important molecules, yet challenges remain for the formation of C(sp3)–C(sp3) bonds that form the core of nearly all organic compounds. Herein, we report a distinct, transition metal-free platform to form such bonds without the need for activating or stabilizing groups on the coupling partners. The reaction is enabled by an unusual single electron transfer in a frustrated ion pair and is complementary in terms of scope to transition metal-catalyzed processes. Moreover, we could further leverage this new mechanistic manifold in the design of other reactions, showing the broad potential of this new reactivity in organic synthesis.
|
Sven Roediger; Philip Boehm; Bill Morandi
|
Organic Chemistry; Organic Synthesis and Reactions
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2023-05-17
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6463c0bda32ceeff2dc08a2d/original/frustrated-ion-pair-enabled-cross-electrophile-coupling-of-unactivated-alkyl-electrophiles.pdf
|
60c74045ee301cc3d0c78a4a
|
10.26434/chemrxiv.7680137.v1
|
Synthetic bPNAs as Allosteric Triggers of Hammerhead Ribozyme Catalysis
|
The biochemistry and structural biology of the hammerhead ribozyme (HHR) has been well-elucidated. The secondary and tertiary structural elements that enable sugar-phosphate bond scission to be be catalyzed by this RNA are clearly understood. We have taken advantage of this knowledge base to test the extent to which synthetic molecules, may be used to trigger structure in secondary structure and tertiary interactions and thereby control HHR catalysis. These molecules belong to a family of molecules we call generally call “bPNAs” based on our work on bifacial peptide nucleic acid (bPNA). This family of molecules display the “bifacial” heterocycle melamine, which acts as a base-triple upon capturing two equivalents of thymine or uracil. Loosely structured internal oligouridylate bulges of 4-20 nucleotides can be restructured as triplex hybrid stems upon binding bPNAs. As such, a duplex stem element can be replaced with a bPNA triplex hybrid stem; similarly, a tertiary loop-stem interaction can be replaced with a loop-bPNA-stem complex. In this chapter, we discuss how bPNAs are prepared and applied to study structure-function turn-on in the hammerhead ribozyme system.
|
Dennis Bong; Yufeng Liang; Jie Mao
|
Biochemistry; Chemical Biology
|
CC BY NC ND 4.0
|
CHEMRXIV
|
2019-02-07
|
https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/60c74045ee301cc3d0c78a4a/original/synthetic-b-pn-as-as-allosteric-triggers-of-hammerhead-ribozyme-catalysis.pdf
|
64c760e5658ec5f7e57927de
|
10.26434/chemrxiv-2023-k0qnb
|
Tunable valence tautomerism in lanthanide-organic alloys
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The electronic structures of the lanthanide (Ln) ions are inimitable and key to advanced materials and technologies. The trivalent ions are ubiquitous and dwarf the use of di- and tetra-valent analogues, which, however, possess vastly different optical and magnetic properties. Hence, alteration of the valence electron count by external stimuli would lead to dramatic changes in materials properties. Compounds exhibiting a temperature-induced, complete Ln(III) ⇄ Ln(II) switch, referred to as a valence tautomeric (VT) transition, are virtually absent. Herein, we present an abrupt and hysteretic VT transition in a lanthanide-based coordination polymer, SmI2(pyrazine)3, driven by the interconversion of closed-shell Sm(II)-pyrazine(0) and paramagnetic Sm(III)-pyrazine(●–) redox pairs. Alloying SmI2(pyrazine)3 with Yb(II) yields isomorphous Sm(1–x)Yb(x)I2(pyrazine)3 solid solutions with VT transition critical temperatures ranging widely from 200 K to ~50 K at ambient pressure. These findings demonstrate a simple strategy to realize thermally switchable magnetic materials with chemically tunable transition temperatures.
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Maja Dunstan; Anna Manvell; Nathan Yutronkie; Frédéric Aribot; Jesper Bendix; Andrei Rogalev; Kasper Steen Pedersen
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Materials Science; Inorganic Chemistry; Organometallic Chemistry; Magnetic Materials; Coordination Chemistry (Inorg.); Lanthanides and Actinides
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CC BY NC ND 4.0
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CHEMRXIV
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2023-08-03
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https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/64c760e5658ec5f7e57927de/original/tunable-valence-tautomerism-in-lanthanide-organic-alloys.pdf
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6275393144bdd5b42458fcfb
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10.26434/chemrxiv-2022-clqmd
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Synthesis and styrene copolymerization of novel phenoxy and benzyloxy ring-substituted octyl phenylcyanoacrylates
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Novel ring-substituted octyl phenylcyanoacrylates, RPhCH=C(CN)CO2CH2(CH2)6CH3 (where R is 3-phenoxy, 4-phenoxy, 4-(4-bromophenoxy), 3-(4-chlorophenoxy), 2-(4-fluorophenoxy), 3-(4-methylphenoxy), 4-(4-methylphenoxy), 4-(4-nitrophenoxy), 3-[3-(trifluoromethyl)phenoxy], 2-benzyloxy, 3-benzyloxy, 4-benzyloxy) were prepared and copolymerized with styrene. The acrylates were synthesized by the piperidine catalyzed Knoevenagel condensation of ring-substituted benzaldehydes and octyl cyanoacetate, and characterized by CHN analysis, IR, 1H and 13C NMR. The acrylates were copolymerized with styrene in solution with radical initiation (ABCN) at 70C. The compositions of the copolymers were calculated from nitrogen analysis.
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Zena Ahmad; Burcin Asilturk; Dana R. Fasman; Erin R. Hocker; Sean P. Markey; Karina Martinez; Aisha Owens; Jasmine S. Ramirez; Oscar Rios; David Villegas; Jack N. Wiley; Lindsay M. Winders; Sara M. Rocus; William S. Schjerven; Gregory B Kharas
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Organic Chemistry; Polymer Science; Organic Compounds and Functional Groups; Organic Synthesis and Reactions; Organic Polymers
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CC BY 4.0
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CHEMRXIV
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2022-05-10
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https://chemrxiv.org/engage/api-gateway/chemrxiv/assets/orp/resource/item/6275393144bdd5b42458fcfb/original/synthesis-and-styrene-copolymerization-of-novel-phenoxy-and-benzyloxy-ring-substituted-octyl-phenylcyanoacrylates.pdf
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