ChemRxiv : the preprint server for chemistry最新文献

{"title":"Synthetic Studies of Maleimide Derivatives for Bioconjugates Polymers by RAFT polymerization.","authors":"S. Gondi","doi":"10.33774/chemrxiv-2021-xhq0n","DOIUrl":"https://doi.org/10.33774/chemrxiv-2021-xhq0n","url":null,"abstract":"An efficient method for the synthesis of maleimides derivatives in toluene in presence of PTSA is described. The method features a broad substrate scope of utility in both simple and complex setting and provide access to valuable derivatives without any column chromatography purification is described.","PeriodicalId":72565,"journal":{"name":"ChemRxiv : the preprint server for chemistry","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45691745","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Computational Study on the Ca2+ Solvation, Coordination Environment, and Mobility in Electrolytes for Calcium Ion Batteries","authors":"Saeid Biria, Shreyas Pathreeker, I. Hosein","doi":"10.33774/chemrxiv-2021-djssr-v2","DOIUrl":"https://doi.org/10.33774/chemrxiv-2021-djssr-v2","url":null,"abstract":"Calcium (ion) batteries are promising next-generation energy storage systems, owing to their numerous benefits in terms of performance metrics, low-cost, mineral abundance, and economic sustainability. A central and critical area to the advancement of the technology is the development of suitable eletrolytes that allow for good salt solubility, ion mobility, electrochemical stability, and reversible redox activity. At this time, the study of different solvent-salt combinations is very limited. Here, we present a computational study on the coordination environment, solvation energetics, and diffusivity of calcium ions over a range of pertinent ionic liquids, cyclic and acylic alkyl carbonates, and specific alkyl nitriles and alkyl formamides, using the salts calcium bis(trifluoromethylsulfonyl)imide (Ca(TFSI)2) and calcium perchlorate (Ca(ClO4)2). Key findings are that several solvents from different solvent classes present comparable solvation environments and mobilities. Ca(TFSI)2 is prefered over Ca(ClO4)2 owing to the former’s mix coordination of Ca2+ to O and N atoms. Ionic liquids with alkyl sulfonate anions provide better coordation over TFSI, which leads to greater diffusivity. Binary organic mixtures (carbonates) provide the best solvation of Ca2+, however, single organic solvents also provide good solvation, such as EC, THF and DMF, as well as some acyclic carbonates. Ion pairing with the salt anion is always present, but can be mitigated through solvent selection, which also correlates to greater mobility; however, there are examples in which strong ion pairing is not significantly adverse to diffusivity. The solvent incorporate into the solvation structure with binary organic mixtures correlates well with the solvation capabilities of the individual solvents. Finally, we show that ionic liquids (specifically alkyl imidazole (cation) alkyl sulfonate (anion) ionic liquids) do not decompose when coordinating at a Ca metal interface, which indicates its promising stability. Overall, this study contributes further generalized understanding of the correlation between solvent and salt and the resultant Ca2+ complexes and Ca2+ mobility in a range of electrolytes, and reveals a range of possible solvents suitable for exploration in calcium (ion) batteries.","PeriodicalId":72565,"journal":{"name":"ChemRxiv : the preprint server for chemistry","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44260349","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A fluorescent amyloid sensor for quantitative super-resolution imaging of amyloid fibril assembly.","authors":"Amandeep Kaur, Liam D. Adair, Sarah R Ball, Elizabeth J. New, M. Sunde","doi":"10.33774/chemrxiv-2021-hhjvc","DOIUrl":"https://doi.org/10.33774/chemrxiv-2021-hhjvc","url":null,"abstract":"Many soluble proteins can self-assemble into macromolecular structures called amyloids, a subset of which are implicated in a range of neurodegenerative disorders. The nanoscale size and structural heterogeneity of prefibrillar and early aggregates, as well as mature amyloid fibrils, pose significant challenges for the quantification of amyloid species, identification of their cellular interaction partners and for elucidation of the molecular basis for cytotoxicity. We report a fluorescent amyloid sensor AmyBlink-1 and its application in super-resolution imaging of amyloid structures. AmyBlink-1 exhibits a 5-fold increase in ratio of the green (thioflavin T) to red (Alexa Fluor 647) emission intensities upon interaction with amyloid fibrils. Using AmyBlink-1, we performed nanoscale imaging of four different types of amyloid fibrils, achieving a resolution of ~30 nm. AmyBlink-1 enables molecular-level visualization and subsequent quantification of morphological features, such as the length and skew of individual amyloid aggregates formed at different times along the amyloid assembly pathway.","PeriodicalId":72565,"journal":{"name":"ChemRxiv : the preprint server for chemistry","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47784748","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spinristor: A Swiss Army Knife of Molecular Electronics","authors":"Esmaeil Farajpour Bonab, Adam Jaroš, Zahra Badri, L. Tučková, M. Straka, C. Foroutan‐Nejad","doi":"10.33774/chemrxiv-2021-9xgrq","DOIUrl":"https://doi.org/10.33774/chemrxiv-2021-9xgrq","url":null,"abstract":"Here, we propose and provide in silico proof of concept of a spinristor; a new molecular electronic component that combines a spin-filter, a rectifier, and a switch, in a single molecule for in-memory processing. It builds on the idea of an open-shell transition metal ion enclosed within an elliptical fullerene connected to the source, drain, and a pair of gate electrodes. The spin- and electronic polarization due to the enclosed metal leads to differential rectification of the electrons at low voltages applied between the source-drain electrodes, VSD. The position of the encapsulated ion can be switched by a combination of a high VSD and a voltage applied between gate electrodes, VG, to switch the direction of the rectification and spin-filtering ratio. The system can thus be used as a switching rectifier and spin-filter, a spinristor. To the best of our knowledge, such a system has no macroscopic counterpart in electronics.","PeriodicalId":72565,"journal":{"name":"ChemRxiv : the preprint server for chemistry","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47113627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"MoloVol: an easy-to-use program to calculate various volumes and surface areas of chemical structures and identify cavities","authors":"Jasmin B. Maglic, Roy Lavendomme","doi":"10.33774/chemrxiv-2021-dss1j","DOIUrl":"https://doi.org/10.33774/chemrxiv-2021-dss1j","url":null,"abstract":"Cavities are a ubiquitous feature of chemical structures encountered in various fields ranging from supramolecular chemistry to molecular biology. They are involved in the encapsulation, transport, and transformation of guest molecules, thus necessitating a precise and accessible tool for estimating and visualizing their size and shape. MoloVol, a free, user-parametrizable, open-source software, developed for calculating a range of geometric features for both unit cell and isolated structures is presented here. MoloVol utilizes up to two spherical probes to define cavities, surfaces, and volumes. The program was optimized by combining an octree data structure with voxel-partitioned space allowing for even high-resolution protein structure calculations at reasonable timescales. MoloVol comes with a user-friendly graphic interface along with a command line interface for high throughput calculations. It was written in C++ and is available on Windows, macOS, and Linux distributions.","PeriodicalId":72565,"journal":{"name":"ChemRxiv : the preprint server for chemistry","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41546177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Red-Emissive Nanocrystals of Cs4MnxCd1-xSb2Cl12 Layered Perovskite","authors":"Emanuela Sartori, Marta Campolucci, D. Baranov, M. Zeng, Stefano Toso, M. Ferretti, Z. Hens, L. Manna, F. Locardi","doi":"10.33774/chemrxiv-2021-d6k2z","DOIUrl":"https://doi.org/10.33774/chemrxiv-2021-d6k2z","url":null,"abstract":"Layered double perovskite are currently investigated as emerging halide-based materials for optoelectronic applications. Herein, we present the synthesis of Cs4MnxCd1-xSb2Cl12 (0 ≤ x ≤ 1) nanocrystals (NCs). X-ray powder diffraction evidences the retaining of the same crystal structure for all the inspected composition; transmission electron microscopy revealed monodisperse particles with a mean size of 10.6 nm. The absorption spectra seem to be mostly determined by transitions related to Sb3+, whereas Mn2+ induced a red emission in the 625 – 650 nm range. The emission intensity and position varies with the Mn2+ content and reaches the maximum for the composition with x = 0.12. Finally, we demonstrated that the photoluminescence quantum yield (PLQY) of the latter NCs was boosted from 0.3% to 3.9% through a post-synthesis treatment. The present work enlarges the knowledge of colloidal layered double perovskite nanocrystals, stimulating future investigations of this emerging class of material.","PeriodicalId":72565,"journal":{"name":"ChemRxiv : the preprint server for chemistry","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45583256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Proton Transfer from a Photoacid to Water: First Principles Simulations and Fast Fluorescence Spectroscopy","authors":"Alice R. Walker, Boning Wu, J. Meisner, M. Fayer, T. Martínez","doi":"10.33774/chemrxiv-2021-cdzlk","DOIUrl":"https://doi.org/10.33774/chemrxiv-2021-cdzlk","url":null,"abstract":"Proton transfer reactions are ubiquitous in chemistry, especially in aqueous solutions. We investigate photo-induced proton transfer between the photoacid 8-hydroxypyrene-1,3,6- trisulfonate (HPTS) and water using fast fluorescence spectroscopy and ab initio molecular dynamics simulations. Photo-excitation causes rapid proton release from the HPTS hydroxyl. Previous experiments on HPTS/water described the progress from photoexcitation to proton diffusion using kinetic equations with two time constants. The shortest time constant has been interpreted as protonated and photoexcited HPTS evolving into an “associated” state, where the proton is “shared” between the HPTS hydroxyl and an originally hydrogen bonded water. The longer time constant has been interpreted as indicating evolution to a “solvent separated” state where the shared proton undergoes long distance diffusion. In this work, we refine the previous experimental results using very pure HPTS. We then use excited state ab initio molecular dynamics to elucidate the detailed molecular mechanism of aqueous excited state proton transfer in HPTS. We find that the initial excitation results in rapid rearrangement of water, forming a strong hydrogen bonded network (a “water wire”) around HPTS. HPTS then deprotonates in ≤3 ps, resulting in a proton that migrates back and forth along the wire before localizing on a single water molecule. We find a near linear relationship between emission wavelength and proton-HPTS distance over the simulated time scale, suggesting that emission wavelength can be used as a ruler for proton distance. Our simulations reveal that the “associated” state corresponds to a water wire with a mobile proton and that the diffusion of the proton away from this water wire (to a generalized “solvent-separated” state) corresponds to the longest experimental time constant.","PeriodicalId":72565,"journal":{"name":"ChemRxiv : the preprint server for chemistry","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45952641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multiple C-C bond formation upon electrocatalytic reduction of CO2 by a molecular catalyst","authors":"Sida Dong, Chen Xu, B. Lassalle‐Kaiser","doi":"10.33774/chemrxiv-2021-j1h90","DOIUrl":"https://doi.org/10.33774/chemrxiv-2021-j1h90","url":null,"abstract":"Molecular macrocycles show very promising electrocatalytic properties for the reduction of carbon dioxide. Up to now, only C1 products were produced by these catalysts. We show here that iron phthalocyanine, a commercially available molecule based on earth abundant elements, can produce light hydrocarbons upon electrocatalytic reduction of CO2 in aqueous conditions and neutral pH. When an electrochemical potential of -0.7 to -1.1 V vs. RHE is applied to a glassy carbon electrode modified with iron phthalocyanine, carbon monoxide is generated as main product. An increasing fraction of hydrogen is observed as the potential is decreased and small amounts of C1 to C4 saturated and unsaturated products are evolved. Control experiments in the absence of CO2 or catalyst does not produce any of these compounds. X-ray spectroscopic analysis of the electrode during catalysis show that the molecular catalyst remains intact and is responsible from the reaction.","PeriodicalId":72565,"journal":{"name":"ChemRxiv : the preprint server for chemistry","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41425845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rhodium Catalyzed Stereoselective Mono-alkenylation of Aryl sp2 C-H Bond via C-N Bond Cleavage: N-allylbenzimidazole as Strategic Alkenylating Agent","authors":"Pragati Biswal, Tanmayee Nanda, S. Banjare, S. Mohanty, P. Ravikumar","doi":"10.33774/chemrxiv-2021-w1d35","DOIUrl":"https://doi.org/10.33774/chemrxiv-2021-w1d35","url":null,"abstract":"A Rh-catalyzed C(sp2)-H alkenylation has been achieved by taking N-allylbenzimidazole as an allylamine congener. This distinctive transformation has been observed for the first time which is attributed to the rigid benzimidazole unit. Lewis acid assisted cleavage of C(sp3)-N bond by coordinating to the N3 of N-allylbenzimidazole has been established. Thus, herein we have demonstrated an unprecedented protocol of domino C-N bond cleavage followed by aryl C(sp2)-H alkenylation. Further, detailed mechanistic studies, control experiments have been conducted to understand the mechanism. The rhodacycle-intermediates involved in the reaction have been isolated and characterized through NMR, HRMS, and single crystal X-ray.","PeriodicalId":72565,"journal":{"name":"ChemRxiv : the preprint server for chemistry","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48562182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sequential Storage and Release of Microdroplets for On and Off-chip Analysis","authors":"Z. Toprakcioglu, T. Knowles","doi":"10.33774/chemrxiv-2021-66zrn","DOIUrl":"https://doi.org/10.33774/chemrxiv-2021-66zrn","url":null,"abstract":"Droplet microfluidic methods have opened up the possibility of studying a plethora of phenomena ranging from biological to physical or chemical processes at ultra-low volumes and high throughput. A key component of such approaches is the ability to trap droplets for observation, and many device architectures for achieving this objective have been developed. A challenge with such approaches is, however, recovering the droplets following their confinement for applications involving further analysis. Here, we present a device capable of generating, confining and releasing microdroplets in a sequential manner. Through a combination of experimental and computational simulations, we shed light on the key features required for successful droplet storage and retrieval. Moreover, we explore the effect of the ow rate of the continuous phase on droplet release, determining that a critical rate is needed to ensure complete droplet deformation through constrictions holding the droplets in place prior to release. Finally, we find that once released, droplets can be retrieved and collected off chip. The ability to generate, store and sequentially release droplets renders such a device particularly promising for future applications where reactions may not only be monitored on-chip, but droplets can be retrieved for further analysis, facilitating new exploratory avenues in the fields of analytical chemistry and biology.","PeriodicalId":72565,"journal":{"name":"ChemRxiv : the preprint server for chemistry","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44839569","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}