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Porous Colloidal Hydrogels Formed by Coordination-Driven Self-Assembly of Charged Metal-Organic Polyhedra chemRxiv Pub Date : 2021-01-22 Zaoming Wang; Gavin Craig; alexandre legrand; Frederik Haase; Saori Minami; Kenji Urayama; Shuhei Furukawa
Introduction of porosity into supramolecular gels endows soft materials with functionalities for molecular encapsulation, release, separation and conversion. Metal-organic polyhedra (MOPs), discrete coordination cages containing an internal cavity, have recently been employed as building blocks to construct polymeric gel networks with potential porosity. However, most of the materials can only be synthesized
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Dynamics of Bound States of Dihydrogen at Cu(I) and Cu(II) Species Coordinated near One and Two Zeolite Framework Aluminium Atoms: A Combined Sorption, INS, IR and DFT Study chemRxiv Pub Date : 2021-01-22 Peter Georgiev; N. Drenchevb; Konstantin I. Hadjiivanov; Jacques Ollivier; Tobias Unruh; Alberto Albinati
The reactivity towards dihydrogen of various copper species, in different coordination environments, decorated by the presence of one and two Al atoms in the framework oz zeolite ZSM-5 are investigated by sorption, INS, FTIR and DFT modeling studies.
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Enhancing the Electrocatalytic Activity and Stability of Prussian Blue Analogues Through the Introduction of Au Nanoparticles in a Core@shell Heterostructure chemRxiv Pub Date : 2021-01-22 Roger Sanchis-Gual; Toribio F. Otero; Marc Coronado-Puchau; Eugenio Coronado
Prussian blue analogues (PBAs) have shown to be useful as earth-abundant electrocatalysts for the Oxygen Evolution Reaction (OER) in acidic, neutral and alkaline media. Still, further improvements can be achieved by increasing their electrical conductivity. In this work, we have obtained and fully characterized a variety of monodisperse core@shell hybrid nanoparticles of Au@PBA (PBA of NiIIFeII and
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Testing the Limitations of MD-based Local Electric Fields Using the Vibrational Stark Effect in Solution: Penicillin G as a Test Case chemRxiv Pub Date : 2021-01-22 Jacek Kozuch; Samuel Schneider; Chu Zheng; Zhe Ji; Richard T Bradshaw; Steven Boxer
Non-covalent interactions underlie nearly all molecular processes in the condensed phase from solvation tocatalysis. Their quantification within a physically consistent framework remains challenging. Experimental vibrational Stark effect (VSE)-based solvatochromism can be combined with molecular dynamics (MD) simulations to quantify the electrostatic forces in solute-solvent interactions for small
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Functional Annotation of an Enzyme Family by Integrated Strategy Combining Bioinformatics with Microanalytical and Microfluidic Technologies chemRxiv Pub Date : 2021-01-22 Pavel Vanacek; Michal Vasina; Jiri Hon; David Kovar; Hana Faldynova; Antonin Kunka; Tomas Buryska; Christoffel P. S. Badenhorst; Stanislav Mazurenko; David Bednar; Uwe T. Bornscheuer; Jiri Damborsky; Zbynek Prokop
Next-generation sequencing technologies enable doubling of the genomic databases every 2.5 years. Collected sequences represent a rich source of novel biocatalysts. However, the rate of accumulation of sequence data exceeds the rate of functional studies, calling for acceleration and miniaturization of biochemical assays. Here, we present an integrated platform employing bioinformatics, microanalytics
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Deep Generative Models for Ligand-based de Novo Design Applied to Multi-parametric Optimization chemRxiv Pub Date : 2021-01-22 Quentin Perron; Olivier Mirguet; Hamza Tajmouati; Adam Skiredj; Anne Rojas; Arnaud Gohier; Pierre Ducrot; Marie-Pierre Bourguignon; Patricia Sansilvestri-Morel; Nicolas Do Huu; Françoise Gellibert; Yann Gaston-Mathé
Multi-Parameter Optimization (MPO) is a major challenge in New Chemical Entity (NCE) drug discovery projects, and the inability to identify molecules meeting all the criteria of lead optimization (LO) is an important cause of NCE project failure. Several ligand- and structure-based de novo design methods have been published over the past decades, some of which have proved useful multiobjective optimization
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Synthesis and Characterization of Bidentate Isonitrile Iron Complexes chemRxiv Pub Date : 2021-01-22 Marion Till; John A. Kelly; Christoph G. P. Ziegler; Robert Wolf; Tianao Guo; Mark R. Ringenberg; Eugen Lutsker; Oliver Reiser
Divalent iron complexes trans-[FeBr2(BINC)2], [Cp*FeCl(BINC)] (Cp* = Me5C5) and [FeBr2(CNAr3NC)2] with chelat-ing bis(isonitrile) ligands BINC (bis(2-isocyanophenyl)phenylphosphonate) and CNAr3NC (2,2’’-diisocyano-3,5,3’’,5’’tetramethyl-1,1’:3’,1’’-terphenyl) have been prepared and characterized. Their subsequent reduction yields di- and trinuclear compounds [Fe3(BINC)6], [Cp*Fe(BINC)]2, [Fe(CNAr3NC)2]2
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Proteomic Database Search Engine for Two-Dimensional Partial Covariance Mass Spectrometry chemRxiv Pub Date : 2021-01-22
We present a protein database search engine for the automatic identi?cation of peptide and protein sequences using the recently introduced method of two-dimensional partial covariance mass spectrometry (2D-PC-MS). Since 2D-PC-MS measurement reveals correlations between fragments stemming from the same or consecutive decomposition processes, the ?first-of-its-kind 2D-PC-MS search engine is based entirely
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Deep Alanine Scanning Reveals Potent Multi-alanine-substituted Protein–protein Interaction Inhibitors chemRxiv Pub Date : 2021-01-21 Xiyun Ye; Yen-Chun Lee; Zachary P. Gates; Yingjie Ling; Jennifer Mortensen; Fan-Shen Yang; Yu-Shan Lin; Bradley Pentelute
Establishing structure–activity relationships is crucial to understand and optimize the activity of peptide-based inhibitors of protein–protein interactions. Single alanine mutagenesis provides limited information toward this goal. To guide multiple simultaneous peptide modifications with retention of biological activity, we used synthetic combinatorial alanine-scanning libraries—in which each position
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Operando Studies of Iodine Species in an Advanced Oxidative Water Treatment Reactor chemRxiv Pub Date : 2021-01-21 Ahmed Moustafa; Alex Evans; Simmon Hofstetter; Jenny Boutros; Parastoo Pourrezaei; Cheng Zhang; Laura Patterson-Fortin; Charles Laing; Carter Goertzen; Richard Smith; Kenneth R Code; Ning Cheng; Peter E R Blanchard; Nathan Bettman; Raquibul Alam; Kerry McPhedran; Zohreh Fallah; Edward Roberts; Michael Gaultois
We present an electrochemical advanced oxidation process (eAOP) reactor employing expanded graphite, potassium iodide (KI), and electrical current, which demonstrates an exceptionally high rate of inactivation of E. coli (6log reduction in viable cells) at low current density 0.6 mA/cm^2), with low contact time (5 minutes) and low concentration of KI (10 ppm). Operando X-ray fluorescence mapping is
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Masked Graph Modeling for Molecule Generation chemRxiv Pub Date : 2021-01-21 Omar Mahmood; Elman Mansimov; Richard Bonneau; Kyunghyun Cho
De novo, in-silico design of molecules is a challenging problem with applications in drug discovery and material design.Here, we introduce a masked graph model which learns a distribution over graphs by capturing all possible conditional distributions over unobserved nodes and edges given observed ones.We train our masked graph model on existing molecular graphs and then sample novel molecular graphs
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Research on Thermal Neutron Shielding Performance of TiB2-Al Composite Materials chemRxiv Pub Date : 2021-01-21 Chao Wang; Zhefu Li; Mengge Dong; Lu Zhang; Jianxing Liu; Xiaozhou Cao; Xiangxin Xue
Although the various excellent properties and preparation methods of TiB2-based composites have been extensively studied, their neutron shielding properties have not received as much attention. In this article, the neutron shielding performance of the previously prepared TiB2-Al composite will be studied. The photo neutron source device was used to carry out neutron irradiation tests on test samples
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Highly Accurate Many-Body Potentials for Simulations of N2O5 in Water: Benchmarks, Development, and Validation chemRxiv Pub Date : 2021-01-21 Vinicius Cruzeiro; Eleftherios Lambros; Marc Riera; Ronak Roy; Francesco Paesani; Andreas Goetz
Dinitrogen pentoxide (N2O5) is an important intermediate in the atmospheric chemistry of nitrogen oxides. Although there has been much research, the processes that govern the physical interactions between N2O5 and water are still not fully understood at a molecular level. Gaining quantitative insight from computer simulations requires going beyond the accuracy of classical force fields, while accessing
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Multiple C–H Activation Enabled Modular Construction of Densely Functionalized Sulfur-Contained Arenes chemRxiv Pub Date : 2021-01-21 Wensen Ouyang; Jianhang Rao; Jie Wang; Yang Gao; Yanping Huo; Qian Chen; Xianwei Li
Modular construction of multiple functionalized arenes from abundant feedstocks, stands as an unremitting pursue goal in synthetic chemistry, which would accelerate the discovery of new drugs an advanced materials. Herein, by using multiple C-H activation strategy, through judicious choice of versatile imidate ester as the key directing group, expedi-ent delivery of molecular libraries of densely functionalized
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In situ lithiated ALD niobium oxide for improved long term cycling of layered oxide cathodes: A thin-film model study chemRxiv Pub Date : 2021-01-21 Abdessalem Aribia; Jordi Sastre; Xubin Chen; Evgeniia Gilshtein; Ayodhya N. Tiwari; Yaroslav E. Romanyuk
Protective coatings applied to cathodes help to overcome interface stability issues and extend the cycle life of Li-ion batteries. However, within 3D cathode composites it is difficult to isolate the effect of the coating because of the additives and non-ideal interfaces. In this study we investigate niobium oxide (NbOx) as cathode coating in a thin-film model system, which provides simple access to
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Benchmarking Graph Neural Networks for Materials Chemistry chemRxiv Pub Date : 2021-01-21 Victor Fung; Jiaxin Zhang; Eric Juarez; Bobby Sumpter
Graph neural networks (GNNs) have received intense interest as a rapidly expanding class of machine learning models remarkably well-suited for materials applications. To date, a number of successful GNNs have been proposed and demonstrated for systems ranging from crystal stability to electronic property prediction and to surface chemistry and heterogeneous catalysis. However, a consistent benchmark
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Amyloid like Aggregates Formed by the Self-Assembly of Proline and Hydroxyproline chemRxiv Pub Date : 2021-01-21 Bharti Koshti; Ramesh, Singh; Vivekshinh Kshtriya; Shanka Walia; Dhiraj Bhatia; khashti Ballabh Joshi; Nidhi Gour
Single amino acid based self-assembled structures have gained a lot of interest recently owing to their pathological significance in metabolite disorders. There is plethora of significant research work which illustrate amyloid like characteristics of assemblies formed by aggregation of single amino acids like Phenylalanine, Tyrosine, Tryptophan, Cysteine and Methionine and its implications in pathophysiology
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Logic and Symbolism of Switchable Porous Framework Materials chemRxiv Pub Date : 2021-01-21 Leila Abylgazina; Irena Senkovska; Stefan Kaskel
Metal-Organic Frameworks (MOFs) are highly porous materials composed of organic linkers connected by inorganic nodes. A unique subset of MOFs shows switchability, the ability to switch between at least two distinct structures differing significantly in porosity. These unique guest dependent pore opening and closing processes offer new opportunities in gas separation, selective recognition, sensing
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Persistent Homology Metrics Reveal Quantum Fluctuations and Reactive Atoms in Path Integral Dynamics chemRxiv Pub Date : 2021-01-21 Yunfeng Hu; Phonemany Ounkham; Ondrej Marsalek; Thomas E. Markland; Bala Krishnamoorthy; Aurora Clark
Nuclear quantum effects (NQEs) are known to impact a number of features associated with chemical reactivity and physicochemical properties, particularly for light atoms and at low temperatures. In the imaginary time path integral formalism, each atom is mapped onto a “ring polymer” whose spread is related to the quantum mechanical uncertainty in the particle’s position i.e. its thermal wavelength.
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On the Common Ground of Thermodynamics and Kinetics: How to Pin Down Overpotential to Reversible Metal Hydride Formation and the Complete Ideal Gas Theory of Reversible Chemical Hydrogen Storage chemRxiv Pub Date : 2021-01-20 Roland Hermann Pawelke
Ti-doped NaAlH4 requires at 125 °C for [AlH4] formation more than twice the equilibrium pressure; while it is straightforward to relate this conditional surplus in hydrogenation pressure respective chemical potential to kinetic hindrance, it appears strange that this matter has not been duly theoretically addressed in literature to this day. The interest in identifying such overpotentials is not of
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Irreversible Inhibition of BoNT/A Protease: Unique Warhead Reactivity and Function Contingent upon a Bifunctional Approach chemRxiv Pub Date : 2021-01-20 Lewis Turner; Alexander Lund Nielsen; Lucy Lin; Sabine Pellett; Takashi Sugane; Margaret Olsen; Eric Johnson; Kim janda
We describe a comprehensive screening campaign of warheads, linked to a hydroxamate chelating anchor, for the modification of Cys165 within the BoNT/A protease. Engaging thorough enzyme kinetics, we detail a remarkable proximity-driven covalent bond with an epoxide warhead, a weak electrophile; yet, one that possessed superior irreversible inhibition, and pharmacological properties, when compared to
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Localized Active Space Pair-Density Functional Theory chemRxiv Pub Date : 2021-01-20 Riddhish Pandharkar; Matthew R. Hermes; Christopher J. Cramer; Donald G. Truhlar; Laura Gagliardi
Accurate quantum chemical methods for the prediction of spin-state energy gaps for strongly correlated systems are computationally expensive and scale poorly with the size of the system. This makes calculations for many experimentally interesting molecules impractical even with abundant computational resources. In previous work, we have shown that the localized active space (LAS) self-consistent field
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A Single Residue on the WPD-Loop Affects the pH Dependency of Catalysis in Protein Tyrosine Phosphatases chemRxiv Pub Date : 2021-01-20 Ruidan Shen; Rory Crean; Sean Johnson; Shina Caroline Lynn Kamerlin; Alvan C. Hengge
Catalysis by protein tyrosine phosphatases (PTPs) relies on the motion of a flexible protein loop (the WPD-loop) that carries a residue acting as a general acid/base catalyst during the PTP-catalyzed reaction. The orthogonal substitutions of a non-catalytic residue in the WPD-loops of YopH and PTP1B results in shifted pH-rate profiles, from an altered kinetic pKa of the nucleophilic cysteine. Compared
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Pulse Dipolar EPR Reveals Double-Histidine Motif Spin-labelling is Robust Against Competitor Ions chemRxiv Pub Date : 2021-01-20 Joshua Wort; Swati Arya; Katrin Ackermann; Alan J. Stewart; Bela Bode
Pulse-dipolar EPR is an appealing strategy for structural characterization of complex systems in solution that complements other biophysical techniques. Significantly, the emergence of genetically encoded self-assembling spin labels exploiting exogenously introduced double-histidine motifs in conjunction with CuII-chelates offers high precision distance determination in systems non-permissive to thiol-directed
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(DMP)DAB–Pd–MAH: A Versatile Pd(0) Source for Precatalyst Formation, Reaction Screening, and Preparative-Scale Synthesis chemRxiv Pub Date : 2021-01-20 Jingjun Huang; Matthew Isaac; Ryan Watt; Joseph Becica; Emma Dennis; Makhsud I. Saidaminov; William A. Sabbers; David Leitch
We report an easily prepared and bench-stable mononuclear Pd(0) source stabilized by a chelating N,N’-diaryldiazabutadiene ligand and maleic anhydride: DMPDAB–Pd–MAH. Phosphine ligands of all types, including bidentate phosphines and large cone angle biarylphosphines, rapidly and completely displace the diazabutadiene ligand at room temperature to give air-stable Pd(0) phosphine complexes. DMPDAB–Pd–MAH
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Mixed Metal-Antimony Oxide Nanocomposites: Low pH Water Oxidation Electrocatalysts with Outstanding Durability at Ambient and Elevated Temperatures chemRxiv Pub Date : 2021-01-20 Luke Sibimol; Manjunath Chatti; Asha Yadav; Brittany Kerr; Jiban Kangsabanik; Tim Williams; Pavel V. Cherepanov; Akshat Tanksale; Bernt Johannessen; Douglas Macfarlane; Rosalie K. Hocking; Aftab Alam; Aswani Yella; Alexandr Simonov
Electrochemical water splitting with a proton-exchange membrane electrolyte provides many advantages for the energy-efficient production of high-purity H2 in a sustainable manner, but the current technology relies on high loadings of expensive and scarce iridium at the anodes, which are also often unstable in operation. To address this, the present work scrutinises the electrocatalytic properties of
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Catalyst Design in C–H Activation: A Case Study in the Use of Binding Free Energies to Rationalise Intramolecular Directing Group Selectivity in Iridium Catalysis chemRxiv Pub Date : 2021-01-20 William Kerr; Gary J. Knox; Marc Reid; Tell Tuttle
Remote directing groups in a bifunctional molecule do not always behave independently of one another in C–H activation chemistries. A combined DFT and experimental mechanistic study to provide enhanced Ir catalysts for chemoselective C–H deuteration of bifunctional aryl primary sulfonamides is described. This provides a pharmaceutically relevant and limiting case study in using binding energies to
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Chain-Growth Condensation Polymerization of Propargyl Electrophiles Enabled by Copper Catalysis chemRxiv Pub Date : 2021-01-20 Han-Li Sun; Da-Qi Liu; Jun-Jie Wang; Dawen Niu; Rong Zhu
In the pursuit of creating macromolecules with controlled molecular weight, sequence, and end groups, condensation polymerization remains an underexploited synthetic tool because of its intrinsic step-growth nature. Introducing chain-growth pathways into condensation polymerization calls for highly efficient chemistries that effect the challenging differentiation between functional groups of the same
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Ab Initio Prediction of High-Temperature Magnetic Relaxation Rates in Single-Molecule Magnets chemRxiv Pub Date : 2021-01-20 Daniel Reta; Jon G. C. Kragskow; Nicholas Chilton
Organometallic molecules based on [Dy(CpR)2]+ cations have emerged as clear front-runners in the search for high-temperature single-molecule magnets. However, despite a growing family of structurally-similar molecules, these molecules show significant variations in their magnetic properties, demonstrating the importance of understanding magneto-structural relationships towards developing more efficient
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Incorporating Fluorescent Nanomaterials in Organically Modified Sol-Gel Materials – Creating Single Composite Optical pH Sensors chemRxiv Pub Date : 2021-01-20 David Bartos; Morten Rewers; Lu Wang; Thomas Just Sørensen
Optical sensors hold the promise of providing the coupling between the tangible and the digital world that we are currently experiencing with physical sensors. The core of optical sensor development lies in materials development, where specific requirements of opposing physicochemical properties create a significant obstacle. The sensor material must provide dye retention, while ensuring porosity for
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Aerobically Stable and Substitutionally Labile α-Diimine Rhenium Dicarbonyl Complexes chemRxiv Pub Date : 2021-01-20
New synthetic routes to aerobically stable and substitutionally labile a-diimine rhenium(I) dicarbonyl complexes are described. The molecules are prepared in high yield from the cis-cis-trans-[Re(CO)2(tBu2bpy)Br2]- anion (2, where tBu2bpy is 4,4'-di-tert-butyl-2,2'-bipyridine), which can be isolated from the one electron reduction of the corresponding 17-electron complex (1). Compound 2 is stable in
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Rapid Analysis and Authentication of Meat Products using the MasSpec Pen Technology chemRxiv Pub Date : 2021-01-20 Abigail N. Gatmaitan; John Q. Lin; Jialing Zhang; Livia Schiavinato Eberlin
Food authenticity and safety are major public concerns due to the increasing number of food fraud cases. Meat fraud is an economically motivated practice of covertly replacing one type of meat with a cheaper alternative, raising health, safety, and ethical concerns for consumers. In this study, we implement the MasSpec Pen technology for rapid and direct meat analysis and authentication. The MasSpec
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High-Performance Non-doped Blue OLEDs based on Efficiently Triplet-Triplet Upconversion and Aggregation-induced Emission chemRxiv Pub Date : 2021-01-20 Pengbo Han; Chengwei Lin; Kaojin Wang; Yanping Qiu; Haozhong Wu; Dongge Ma; Anjun Qin; Ben Zhong Tang
Triplet-triplet upconversion (TTU), where two low-energy triplet excitons are converted to one higher energy singlet exciton, is excellent approach to break through the theoretical limit of the pure fluorescent organic light-emitting diodes (OLEDs) by 5%. To data, however, the reported emitters with high emission efficiency and efficiently TTU in film state are rare. Herein, we design the blue aggregation-induced
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Systematic Study of the Thermal Properties of Zeolitic Frameworks chemRxiv Pub Date : 2021-01-20 Maxime Ducamp; François-Xavier Coudert
We report a systematic study of the thermal and mechanical properties of 134 pure SiO2 zeolites through DFT-based calculations by making use of the quasi-harmonic approximation (out of a total of 242 known fully ordered zeolitic frameworks). The comparison of our results with reported experimental data for several zeolites revealed a very good accuracy and validated our simulation methodology. We observe
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Heterogeneous Adsorption and Local Ordering of Formate on a Magnetite Surface chemRxiv Pub Date : 2021-01-20 Marcus Creutzburg; Kai Sellschopp; Steffen Tober; Elin Grånäs; Vedran Vonk; Wernfried Mayr-Schmölzer; Stefan Müller; Heshmat Noei; Gregor Vonbun-Feldbauer; Andreas Stierle
We report a novel heterogeneous adsorption mechanism of formic acid on the magnetite (111) surface. Our experimental results and DFT calculations give evidence for dissociative adsorption of formic acid in quasi-bidentate and chelating geometries. The latter is induced by the presence of iron vacancies at the surface, making oxygen atoms accessible for hydrogen atoms from dissociated formic acid. DFT
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Enantioselective Conjugate Addition of Catalytically Generated Zinc Homoenolate chemRxiv Pub Date : 2021-01-20 Yoshiya Sekiguchi; Naohiko Yoshikai
We report herein an enantioselective conjugate addition reaction of a zinc homoenolate, catalytically generated via ring opening of a cyclopropanol, to an α,β-unsaturated ketone. The reaction is promoted by a zinc aminoalkoxide catalyst generated from Et2Zn and a chiral β-amino alcohol to afford 1,6- diketones, which undergo, upon heating, intramolecular aldol condensation to furnish highly substituted
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Fluoride Anions in All-Silica Zeolites: Studying Preferred Fluoride Sites and Dynamic Disorder with Density Functional Theory Calculations chemRxiv Pub Date : 2021-01-20 Michael Fischer
In all-silica zeolites synthesised via the “fluoride route”, the fluoride anions are typically incorporated in small cages, forming [SiO4F]- trigonal bipyramids. While diffraction and NMR experiments can elucidate the fluoride location(s) and the occurrence/absence of dynamic disorder, they provide limited insights into the factors that determine equilibrium position and dynamic behaviour. To develop
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Miniaturized Analysis of Amylopectin Chain Length Distribution by Fluorescence-Assisted Capillary Electrophoresis (FACE) down to Single Starch Granules chemRxiv Pub Date : 2021-01-19 amandine pruvost; stanislas helle; nicolas szydlowski; Christian ROLANDO
In the present work, we developed a miniaturized method for determining amylopectin chain length distribution (CLD) by fluorescence-assisted capillary electrophoresis (FACE). The method relies on single granule entrapping into capillaries followed by direct starch gelatinization and amylopectin debranching on carbograph-based solid phase extraction (SPE) cartridges. Sample desalting on HypersepTM tips
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α-Glucosidic Hydroquinone Derivatives from Viburnum Erosum chemRxiv Pub Date : 2021-01-19 Jinyoung Park; Jiho Lee; Hyeon S. Jang; Birang Jeong; Seong Y. Choi; Juyeol Kim; Yong S. Kwon; Heejung Yang
Six new compounds (1−6) were isolated from the leaves of Viburnum erosum along with four known compounds 7−10. The structures were determined by NMR and MS spectroscopic analyses, and their absolute configurations were established by chemical and spectroscopic methods. Compounds 1–6 were α-glucosidic hydroquinone derivatives with different linear monoterpenoid structures. Compounds 1−10 were also evaluated
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A Bifunctional Iminophosphorane Squaramide Catalyzed Enantioselective Synthesis of Hydroquinazolines via Intramolecular Aza-Michael Addition to α,β-Unsaturated Esters chemRxiv Pub Date : 2021-01-19 Guanglong Su; Connor J. Thomson; Ken Yamazaki; Daniel Rozsar; Kirsten Christensen; Trevor Hamlin; Darren J. Dixon
An efficient synthesis of enantioenriched hydroquinazoline cores via a novel bifunctional iminophosphorane squaramide catalyzed intramolecular aza-Michael addition of urealinked α,β-unsaturated esters is described. The methodology exhibits a high degree of functional group tolerance around the forming hydroquinazoline aryl core and wide structural variance on the nucleophilic N atom of the urea moiety
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Visible-Light-Induced Deep Aerobic Oxidation of Alkyl Aromatics chemRxiv Pub Date : 2021-01-19 changchengwang wang; guoxiang zhang; zhiwei zuo; rong zeng; dandan zhai; Feng Liu; Zhangjie Shi
Oxidation is a major chemical process to produce oxygenated chemicals in both nature and chemical industry. Currently, industrial deep oxidation processes from polyalkyl benzene are major routes to produce benzoic acids and benzene polycarboxylic acids (BPCAs), while to some extent suffering from the energy-intensive and potentially hazardous drawbacks and the sluggish separation issues. In this report
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Is a Single Conformer Sufficient to Describe the Reorganization Energy of Amorphous Organic Transport Materials? chemRxiv Pub Date : 2021-01-19 Jacob Terence Blaskovits; Kun-Han Lin; Raimon Fabregat; Iwona Swiderska; Hélène Wu; Clemence Corminboeuf
The reorganization energy (λ), which quantifies the structural rearrangement of a molecule when accommodating a charge, is a key parameter in the evaluation of charge mobility in molecular solids. However, it is unclear how λ is influenced by conformational isomerism, which co-exist in amorphous solids. Here, we examine the conformational space of a family of model amorphous organic hole transport
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Synergistic Inhibition of SARS-CoV-2 Replication using Disulfiram and Remdesivir chemRxiv Pub Date : 2021-01-19 Ting Chen; Cheng-Yin Fei; Yi-Ping Chen; Karen Sargsyan; Chun Ping Chang; Hanna S. Yuan; Carmay Lim
The SARS-CoV-2 replication and transcription complex (RTC) comprising nonstructural protein (nsp) 2-16 plays crucial roles in viral replication, reducing the efficacy of broad-spectrum nucleoside analog drugs such as remdesivir and in evading innate immune responses. Most studies target a specific viral component of the RTC such as the main protease or the RNA-dependent RNA polymerase. In contrast
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Substituent Effects of Amines on Genipin Dye Formation – Insights into Dye Origins chemRxiv Pub Date : 2021-01-19 Fiona Jeeva; Chris Caputo
Genipin, a naturally occurring iridoid, represents an interesting class of reactive dyes. This colorless molecule produces brilliant blue dyes in the presence of primary aliphatic amines. The mechanism behind this unique reaction has been suggested to proceed via an oxidative polymerization reaction, albeit few studies have investigated this process. By utilizing aromatic amines, we demonstrate that
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Detection of Metabolite-Protein Interactions in Complex Biological Samples by High-Resolution Relaxometry: Towards Interactomics by NMR chemRxiv Pub Date : 2021-01-19 Ziqing Wang; Veronica Ghini; Pavel Kaderavek; Simone Pisano; Milan Zachrdla; Philippe Pelupessy; Morgan Kazmierczak; Thorsten Marquardsen; Jean-Max Tyburn; Guillaume Bouvignies; Giacomo Parigi; Claudio Luchinat; Fabien Ferrage
In this manuscript, we introduce an NMR method to investigate the interaction of metabolites and other small molecules with proteins in biological fluids. Our approach, based on high-resolution relaxometry identifies the interaction of small molecules with proteins in blood serum and is used for the quantitative analysis of binding competition in situ.
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Large Scale Membrane Movement Induced by a Cation Switch chemRxiv Pub Date : 2021-01-19 Laura. H. John; Gail. M. Preston; Mark S. P. Sansom; Luke Clifton
A biomembrane sample system where millimolar changes of cations induce reversible large scale (≥ 200 Å) changes in the membrane-to-surface distance is described. The system composes of a free-floating bilayer (FFB), formed adjacent to a self-assembled monolayer (SAM). To examine the membrane movements, differently charged FFBs in the presence and absence of Ca2+ and Na+, respectively, were examined
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Activated Self-Resolution and Error-Correction in Catalytic Reaction Networks chemRxiv Pub Date : 2021-01-19 Fredrik Schaufelberger; Olof Ramstrom
To understand the emergence of function in complex reaction networks is a primary goal of systems chemistry and origin-of-life studies. Especially challenging is the establishment of systems that simultaneously exhibit several functionality parameters that can be independently tuned. In this work, a multifunctional complex reaction network of nucleophilic small molecule catalysts for the Morita-Baylis-Hillman
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A Heavily Substituted Manganite in an Ordered Nanocomposite for Long-Term Energy Applications chemRxiv Pub Date : 2021-01-19 Federico Baiutti; Francesco Maria Chiabrera; Matias Acosta; David R. Diercks; David Parfitt; José Santiso; Xuejing Wang; Andrea Cavallaro; Alex Morata; Alexander Chroneos; Judith L. MacManus-Driscoll; Albert Tarancón; Haiyan Wang
The implementation of nano-engineered composite oxides opens up the way towards the development ofa novel class of superior energy materials. Vertically aligned nanocomposites are characterized by acoherent, dense array of vertical interfaces, which allows for the extension of local effects to the wholevolume of the material. Here, we use such a unique architecture to fabricate highly electrochemicallyactive
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Stereoselectivity Predictions for the Pd-Catalyzed 1,4-Conjugate Addition Using Q2MM chemRxiv Pub Date : 2021-01-18 Jessica Wahlers; Michael Maloney; Farbod Salahi; Anthony Rosales; Paul Helquist; Per-Ola Norrby; Olaf Wiest
The parameterization of a transition state force field for the title reaction is described. Validation for 82 literature examples leads to a MUE of 1.8 kJ/mol and an R2 of 0.877 between computed and experimental stereoselectivities. The use if the TSFF is demonstrated for a virtual library of 27 ligands and 59 enones.
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Interaction Region Indicator (IRI): A Very Simple Real Space Function Clearly Revealing Both Chemical Bonds and Weak Interactions chemRxiv Pub Date : 2021-01-18 Tian Lu; qinxue chen
Graphically revealing interaction regions in a chemical system enables chemists to notice the areas at a glance where significant interactions have formed, it is very helpful in studying chemical bonds, intermolecular and intramolecular interactions. Reduced density gradient (RDG) has already been widely employed in literatures to visually exhibit weak interaction regions, in fact it also has the ability
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Too Much of a Good Thing? Assessing Performance Tradeoffs of Two-Electron Compounds for Redox Flow Batteries chemRxiv Pub Date : 2021-01-18 Bertrand Neyhouse; Alexis Fenton Jr; Fikile Brushett
Engineering redox-active compounds to support stable multi-electron transfer is an emerging strategy for enhancing the energy density and reducing the cost of redox flow batteries (RFBs). However, when sequential electron transfers occur at disparate redox potentials, increases in electrolyte capacity are accompanied by decreases in voltaic efficiency, restricting the viable design space. To understand
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Remarkable Size Effect on Photophysical and Nonlinear Optical Properties of All-Carboatomic Rings, Cyclo[18]carbon and Its Analogues chemRxiv Pub Date : 2021-01-13 Zeyu Liu; Tian Lu; Aihua Yuan; Qinxue Chen; Xiufen Yan
Inspired by recent experimental observation of molecular morphology and theoretical predictions of multiple properties of cyclo[18]carbon, we systematically studied photophysical and nonlinear optical properties of cyclo[2N]carbons (N = 3−15) allotropes through density functional theory. This work unveils the unusual optical properties of the sp-hybridized carbon rings with different sizes. The remarkable
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Emergence of a Promiscuous Peroxidase Under Non-Equilibrium Conditions chemRxiv Pub Date : 2021-01-13 Sumit Pal; Antara Reja; Subhajit Bal; Baishakhi Tikader; Sandip Kar; Dibyendu Das
In the far from equilibrium state of living matter, energy is consumed to fuel the metabolic networks of enzymatic reactions. The emergence of protometabolic pathways in primeval earth is intricately related to the evolutionary journey of modern enzymes. Fundamental understanding of such energy driven generation of early catalytic systems would help us recognize the conditions required for the minimal
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Dataset of Noncovalent Intermolecular Interaction Energy Curves for 24 Small High-Spin Open-Shell Dimers chemRxiv Pub Date : 2021-01-13 Katarzyna Madajczyk; Piotr Zuchowski; Filip Brzęk; Łukasz Rajchel; Dariusz Kędziera; Marcin Modrzejewski; Michał Hapka
We introduce a dataset of 24 interaction energy curves of open-shell noncovalent dimers, referred to as the O24x5 dataset. The dataset consists of high-spin dimers up to eleven atoms selected to assure diversity with respect to interactions types: dispersion, electrostatics and induction. The benchmark interaction energies are obtained at the restricted open-shell CCSD(T) level of theory with complete
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Cobalt Catalysis Enables Regioselective Ring-opening of Epoxides with Aryl Halides chemRxiv Pub Date : 2021-01-13 Aleksandra Potrząsaj; Mateusz Musiejuk; Wojciech Chaładaj; Maciej Giedyk; Dorota Gryko
Ring-opening of epoxides furnishing either linear or branched products belongs to the group of classic transformations in organic synthesis. However, the regioselective cross-electrophile coupling of aryl epoxides with aryl halides still represents a key challenge. Herein, we report vitamin B12/Ni dual-catalytic system that allows for the selective synthesis of linear products under blue-light irradiation
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Hetero-helicenes Synthesis Through 1,3-Dipolar-Cycloaddition of Sydnones with Arynes: Synthesis, Origins of Selectivity and Application to pH Triggered Chiroptical Switch with CPL-sign Reversal chemRxiv Pub Date : 2021-01-13 Expédite Yen-Pon; Floris Buttard; Lucas Frédéric; Pierre Thuéry; Frédéric Taran; Grégory Pieters; Pier Alexandre Champagne; Davide Audisio
The regioselective access to hetero-helicenes through 1,3-dipolar cycloaddition of sydnones with arynes is described. Novel access to sydnones and poly-(hetero)aromatic aryne precursors allowed the introduction of chemical diversity over multiple positions of the helical scaffolds. The origins of the unconventional regioselectivity during the cycloaddition steps was systematically investigated using
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Application of the “EigenValue Analysis (EVANS)” Methodology to Build Quantitative Structure Pharmacokinetic Relationship Models chemRxiv Pub Date : 2021-01-13 Anish Gomatam; Blessy Joseph; Mushtaque S. Shaikh; Poonam Advani; Evans C. Coutinho
We present EigenValue ANalySis (EVANS), a QSPR methodology that considers 3D molecular information of enantiomeric ensembles of chiral molecules without the need to perform an alignment step. EVANS follows an intricate molecular modelling protocol that generates orthogonal eigenvalues from hybrid matrices of physicochemical properties and 3D structure; these eigenvalues are used as independent variables
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Modeling LiF and FLiBe Molten Salts with Robust Neural Network Interatomic Potentials chemRxiv Pub Date : 2021-01-13 Stephen T. Lam; Qing-Jie Li; Ronald Ballinger; Charles Forsberg; Ju Li
Lithium-based molten salts have attracted significant attention due to their applications in energy storage, advanced fission reactors and fusion devices. Lithium fluorides and particularly 66.6%LiF-33.3¾F2 (Flibe) are of considerable interest in nuclear systems, as they show an excellent combination of desirable heat-transfer and neutron-absorption characteristics. For nuclear salts, the range of
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Pyrolysis of Complexes of Metallosulphophthalocyanines with Chitosan for Obtaining Graphite-like structures chemRxiv Pub Date : 2021-01-13 Natalia Lebedeva; Sabir Guseinov; Elena Yurina; Yury Gubarev; Anatoly V'yugin
Highlights: Polymer complexes of chitosan with copper and cobalt phthalocyanines were obtained Decomposition products of chitosan and polymer complexes with metal phthalocyanines were determined Pyrolysis of chitosan and its polymer complexes with metallosulphophthalocyanines leads to the formation of carbonizates The introduction of copper phthalocyanine into the composition of the polymer complex
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Unveiling Potent Photooxidation Behavior of Catalytic Photoreductants chemRxiv Pub Date : 2021-01-13 Karina Targos; Oliver P. Williams; Zachary Wickens
We describe a photocatalytic system that reveals latent photooxidant behavior from one of the most reducing conventional photoredox catalysts, N-phenylphenothiazine (PTH). This aerobic photochemical reaction engages difficult to oxidize feedstocks, such as benzene, in C(sp2)–N coupling reactions through direct oxidation. Mechanistic studies are consistent with activation of PTH via photooxidation and
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