ChemRxiv最新文献

{"title":"Structure-selection dynamics of cobalt nanoparticles from solution synthesis and their impact on the catalytic functionality","authors":"Carlos, Triana, Greta, Patzke, Florian, Keller, Marcella, Iannuzzi, Lukas, Reith, Kenneth, Marshall, Wouter, van Beek","doi":"10.26434/chemrxiv-2024-q51c9","DOIUrl":"https://doi.org/10.26434/chemrxiv-2024-q51c9","url":null,"abstract":"Resolving the three-dimensional structure of transition metal oxide nanoparticles (TMO-NPs), upon self-restructuring from solution is crucial for tuning their structure-functionality. Yet, this remains challenging as this process entails complex struc-ture fluctuations, which are difficult to track experimentally, and hence, hinder the knowledge-driven optimization of TMO-NPs. Herein, we combine high-energy synchrotron X-ray absorption/scattering data with atomistic multiscale simulations to investigate the self-restructuring of self-assembled Co-NPs from solution under dark or photocatalytic water oxidation condi-tions at distinct reaction times and atomic length-scales. Using the atomic range order as a descriptor, we reveal that dissolu-tion of a Co-salt in borate buffer leads to a self-optimization route forming disordered oxyborite Co3BOx-NPs unveiling a high oxygen yield due to the formation of surface oxo/hydroxo adsorbates. Those NPs further self-restructure into distorted Co3O4-NPs, and lastly, into CoOOH-NPs through a rate-limiting step integrating Co3+-states during the course of a representative photocatalytic assay. Self-restructuring does not proceed from amorphous-to-ordered states, but through stochastic fluctua-tions of atomic nanoclusters of 10 Å domain size. Our key insight into the structure-selection dynamics of TMO-NPs from solution offers new routes for tunning their structure-function relationships.","PeriodicalId":9813,"journal":{"name":"ChemRxiv","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214930","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":"Electron Donor-Functionalized Pyrenes with Amplified Spontaneous Emission for Violet-Blue Electroluminescent Devices Beyond the Spin Statistical Limit","authors":"Alexander J. C. , Kuehne, Philipp J., Welscher, Daniel, Straub, Florian, Stuempges, A. Lennart, Respondek, Birgit, Esser","doi":"10.26434/chemrxiv-2024-38nsp","DOIUrl":"https://doi.org/10.26434/chemrxiv-2024-38nsp","url":null,"abstract":"Direct electrically pumped organic lasers remain inaccessible to date, due to an interplay of different adverse effects. The most important of these effects are, insufficient charge carrier mobility in the organic material, accumulation of triplet excitons upon charge injection, and absorption from the electrodes in the device. While triplet state management can be achieved using molecules that recycle triplet states into emissive singlet states, these molecules only rarely support amplified emission. Pyrene derivatives not only show excellent charge transport properties, but their rigid π-conjugated structure also entails excellent electro- and photoluminescence efficiency. Pyrenes exhibit very low-lying first excited triplet states, rendering this class of molecules interesting for ultrafast upper-level reverse intersystem crossing. This process could be useful to counteract the triplet accumulation in organic lasers. Here, we functionalize pyrenes with electron-rich moieties of different donor strength. Through comprehensive spectroscopic and quantum chemical analysis, we correlate the nature of the excited state with the optical properties, excited state lifetimes, amplified spontaneous emission, and triplet recycling. We report a donor functionalized pyrene that overcomes the spin-statistical limit of conventional organic emitters with a spin factor ηST of up to 0.43 and low threshold Eth for amplified spontaneous emission down to 1.73 µJ cm-2.","PeriodicalId":9813,"journal":{"name":"ChemRxiv","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214938","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":"Circularly Polarized Room Temperature Red Phosphorescence from a [9]-Heterohelicene Diimide","authors":"Sankar, Jeyaraman, Shivangee, Jha, Kundan Singh, Mehra, Pradip Kumar, Mondal, Camelia, Dutta, Jatish, Kumar, Sentamizh Selven, Ramalingam","doi":"10.26434/chemrxiv-2024-44vd8","DOIUrl":"https://doi.org/10.26434/chemrxiv-2024-44vd8","url":null,"abstract":"Circularly polarized room temperature phosphorescence (CP-RTP) in the red region is fascinating, however, challenging to achieve in organic molecules. The difficulty stems from two necessary conditions required to design such molecules. Firstly, achieving circularly polarized luminescence, with higher emission quantum yield in the longer wavelength region is challeng-ing. Secondly, attaining phosphorescence from such molecules under ambient conditions is difficult. Achieving both the cri-teria together in a single molecule is ambitious. In this work, we devise a novel design strategy to realize CP-RTP from a [9]-heterohelicene diimide. The designed molecule possesses helical chirality and an extended conjugation affording chiroptical responses in the red region. Interestingly a four-fold increment in the dissymmetry factor has been achieved by switching the solvent polarity. Furthermore, the incorporation of sulphur atom in the molecular framework facilitates a prolonged emis-sion lifetime of 1.09 ms under ambient conditions, making it the only example of a rylene diimide exhibiting CP-RTP.","PeriodicalId":9813,"journal":{"name":"ChemRxiv","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214980","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":"Single-Molecule Sensitivity in Hot Microcavities in the Unstable Regime","authors":"Carlos A., Saavedra Salazar, Sushu, Wan, Nasrin, Asgari, Lisa-Maria, Needham, Randall, Goldsmith, Joel, Yuen-Zhou, Brendan, Cullinane, Julia, Rasch, Daniel, Sole-Barber, Michael, Reitz","doi":"10.26434/chemrxiv-2024-xgtxg","DOIUrl":"https://doi.org/10.26434/chemrxiv-2024-xgtxg","url":null,"abstract":"Fiber Fabry-Perot microcavities (FFPCs) enhance light-matter interactions by localizing light in time and space. A new detection scheme exploiting photothermal non-linearities and Pound-Drever-Hall frequency locking enabled label-free detection of solution-phase single biomolecules with unprecedented sensitivity. Here, we deploy a combination of experiment and simulation to provide a quantitative mechanism for the observed single-molecule sensitivity and achieve quantitative agreement with experiment. Key elements of the mechanism include maintaining the FFPC in an unstable regime, allowing it to rapidly shift to hot and cold pho-tothermal equilibria upon perturbation. We show how Brownian molecular trajectories introducing resonance fluctuations less than one thousandth of a linewidth can produce selective and highly amplified responses as long as the perturbations exist in a specific and tunable frequency window termed the molecular velocity filter window. The model’s predictive capacity suggest it will be an im-portant tool to identify new regimes of single-molecule hydrodynamic profiling.","PeriodicalId":9813,"journal":{"name":"ChemRxiv","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214740","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":"Novel Azaspirooxindolinone-Based PROTACs for Selective BTK Degradation and Enhanced Anticancer Activity","authors":"Viswanath, Das, Naveen Kumar , Rampeesa, Rambabu , Gundla, Gopal , Muddasani, Sudhakar , Tangallapally, Sreenivasa , Anugu, Soňa , Gurská, Juan Bautista , De Sanctis, Petr, Džubák, Marián , Hajdúch","doi":"10.26434/chemrxiv-2024-pxdtn-v2","DOIUrl":"https://doi.org/10.26434/chemrxiv-2024-pxdtn-v2","url":null,"abstract":"Proteolysis targeting chimera (PROTAC) facilitates the degradation of specific endogenous proteins via the E3 ubiquitin ligase pathway. This study evaluates nine PROTAC derivatives of azaspirooxindolinone targeting IL-2 inducible T cell kinase (ITK) and Bruton’s Tyrosine Kinase (BTK), which are implicated in hematological malignancies, autoimmune diseases, allergies, and neuroinflammation. Among all the tested compounds, three (PROTACs 7, 14, and 25) exhibited high cytotoxicity (IC50 < 10 µM) against BTK- and ITK-positive cancer cell lines, while showing no cytotoxicity against non-cancer fibroblast cells and normal T/B-cell lymphocytes. Despite having the highest docking score of -12.1 kcal/mol, PROTAC 7 did not reduce BTK or ITK protein levels in treated cells. Similarly, PROTAC 14, with a docking score of -11.2 kcal/mol, and a high cytotoxic against RAMOS cells did not reduce BTK levels. PROTAC 25, also with a docking score of -11.2 kcal/mol, was notably effective in inducing BTK degradation in a proteasome-dependent manner, which was inhibited in the presence of bortezomib. PROTAC 25 degradation of BTK led to the inhibition of BTK phosphorylation and downstream activation of p38 in lipopolysaccharide and IgM-stimulated RAMOS cells. In conclusion, we report a PROTAC derivative (25) of azaspirooxindolinone that shows significant activity against BTK-high cells.","PeriodicalId":9813,"journal":{"name":"ChemRxiv","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214931","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":"Chemoinformatic characterization of NAPROC-13: A database for natural product 13C NMR dereplication","authors":"José L., Medina-Franco, Juan F., Avellaneda-Tamayo, Naicolette A., Agudo-Muñoz, Javier E., Sánchez-Galán, José Luis, López-Pérez","doi":"10.26434/chemrxiv-2024-spksf-v2","DOIUrl":"https://doi.org/10.26434/chemrxiv-2024-spksf-v2","url":null,"abstract":"Natural products (NPs) are secondary metabolites of natural origin with broad applications across various human activities, particularly discovering bioactive compounds. Structural elucidation of new NPs entails significant cost and effort. On the other hand, the dereplication of known compounds is crucial for the early exclusion of irrelevant compounds in contemporary pharmaceutical research. NAPROC-13 stands out as a publicly accessible database, providing structural and 13C NMR spectroscopic information for over 25,000 compounds, rendering it a pivotal resource in natural product (NP) research, favoring open science. This study seeks to quantitatively analyze the chemical content, structural diversity, and chemical space coverage of NPs within NAPROC-13, compared to FDA-approved drugs and a very diverse subset of NPs, UNPD-A. Findings indicated that NPs in NAPROC-13 exhibit comparable properties to those in UNPD-A, albeit showcasing a notably diverse array of structural content, scaffolds, ring systems of pharmaceutical interest, and molecular fragments. NAPROC-13 covers a specific region of the chemical multiverse (a generalization of the chemical space from different chemical representations) regarding physicochemical properties and a region as broad as UNPD-A in terms of structural features represented by fingerprints.","PeriodicalId":9813,"journal":{"name":"ChemRxiv","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214929","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":"Molecular simulation study of all-silica zeolites for the adsorptive removal of airborne chloroethenes","authors":"Michael, Fischer","doi":"10.26434/chemrxiv-2024-w6kxl","DOIUrl":"https://doi.org/10.26434/chemrxiv-2024-w6kxl","url":null,"abstract":"Chloroethenes are produced and consumed in various industrial processes. As the release of these compounds into air, water, and soils can pose significant risks to human health and the environment, different techniques have been exploited to prevent or remediate chloroethene pollution. Although several previous experimental and computational studies investigated the removal of chloroethenes using zeolite adsorbents, their structural diversity in terms of pore size and pore topology has hardly been explored so far. In this work, molecular simulations using validated empirical force field parameters were used to study the gas-phase adsorption of chloroethenes in 16 structurally distinct zeolite frameworks. As all these frameworks are synthetically accessible in high-silica form, the simulations used purely siliceous zeolite models. In the most relevant concentration range (0.1 to 10 ppm by volume), substantial uptakes of tri- and tetrachloroethene were computed for several zeolite frameworks, prominently EUO, IFR, MTW, MOR, and BEA. In contrast, vinyl chloride uptakes were always too low to be of practical relevance for adsorptive removal. For selected frameworks, simulation snapshots were analysed to investigate the impact of pore shape and, at higher uptakes, guest-guest interactions on the adsorption behaviour. Hence, this study not only identifies zeolites that should be prioritised in future investigations, but also contributes to the microscopic understanding of chloroethene adsorption in crystalline microporous materials.","PeriodicalId":9813,"journal":{"name":"ChemRxiv","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214937","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":"The diastereoselective synthesis of unsymmetrically 2,2\"-disubstituted biferrocenesdiphosphine","authors":"Yaping Dorcas, Wang","doi":"10.26434/chemrxiv-2024-hjjvc","DOIUrl":"https://doi.org/10.26434/chemrxiv-2024-hjjvc","url":null,"abstract":"Two sets of unsymmetrically 2,2\"-disubstituted biferrocenes derivatives was diastereoselective synthesized by Negishi coupling reaction. The coupling reaction of (R)-1- (N,N-dimethylamino)ethylferrocene with racemic 2-bromo-iodoferrocene led to two diastereomeric products. Further selective transformations on these coupling products allowed them transformed intocorresponding2,2\"-disubstituted biferrocenes diphosphines as potential asymmetric ligands and catalysts.","PeriodicalId":9813,"journal":{"name":"ChemRxiv","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214982","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":"Reaction-diffusion coupling across scales during the induction period of methanol-to-olefin conversion over ZSM-5 catalysts","authors":"Toyin, Omojola","doi":"10.26434/chemrxiv-2024-wpr4m","DOIUrl":"https://doi.org/10.26434/chemrxiv-2024-wpr4m","url":null,"abstract":"The coupling of reaction and diffusion across the catalyst pore, grain, pellet and reactor bed has been studied using a combination of novel theoretical concepts for incorporating dynamics into kinetics, and a particle-resolved transient microkinetic model applied to temperature-programmed desorption (TPD), and step response studies of methanol, and dimethyl ether over ZSM-5 catalysts, respectively. A resolution of TPD profiles showcases the coupling between adsorption, desorption, and surface diffusion across scales. Six dynamic models are investigated to describe the 44-min induction period in the first step-response cycle and the 95% reduction in induction period in subsequent step-response cycles of dimethyl ether conversion at constant temperature. These include coverage, fixed site-interconversion, dynamic site-interconversion, mass transport of gas, and adsorbed species, and anomalous surface diffusion. None of these dynamic models could explain the overall step-response studies. A combination of adsorption, desorption, and surface reaction of dimethyl ether occurs alongside with competitive adsorption of water and methanol leading to a series of stable intermediates that produce propylene after a 44-min induction period. These intermediates are best described within the methoxymethyl mechanism. The reduction in induction period is due to high binding energies of dimethyl ether such that lower competitive adsorption occurs, fewer stable intermediates exist and a more direct pathway towards propylene formation is followed. The optimum surface coverage of the dissociative products of dimethyl ether (surface methoxy groups, methanol) is the key descriptor that governs the changing induction period behaviour at constant temperature. This site-distribution has a major influence on the dynamic reactor models which predict catalyst activity and product selectivity during methanol-to-olefin conversion. First-principles particle-resolved transient microkinetic models bridge the gap between transient molecular models for the pores and microkinetic models for the grain, pellet, and reactor bed scales.","PeriodicalId":9813,"journal":{"name":"ChemRxiv","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214981","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":"BindingDB in 2024: a FAIR Knowledgebase of Protein-Small Molecule Binding Data","authors":"Michael K., Gilson, Linda, Hwang, Stephen K, Burley, Carmen I, Nitsche, Christopher, Southan, W. Patrick, Walters, Tiqing, Liu","doi":"10.26434/chemrxiv-2024-v9ckg","DOIUrl":"https://doi.org/10.26434/chemrxiv-2024-v9ckg","url":null,"abstract":"BindingDB (bindingdb.org) is a public, web-accessible database of experimentally measured binding affinities between small molecules and proteins, which supports diverse applications including medicinal chemistry, biochemical pathway annotation, training of artificial intelligence models, and computational chemistry methods development. This update reports significant growth and enhancements since our last review in 2016. Of note, the database now contains 2.9 million binding measurements spanning 1.3 million compounds and thousands of protein targets. This growth is largely attributable to our unique focus on curating data from US patents, which has yielded a substantial influx of novel binding data. Recent improvements include a remake of the website following responsive web design principles, enhanced search and filtering capabilities, new data download options and webservices, and establishment of a long-term data archive replicated across dispersed sites. We also discuss BindingDB's positioning relative to related resources, its open data sharing policies, insights gleaned from the dataset, and plans for future growth and development.","PeriodicalId":9813,"journal":{"name":"ChemRxiv","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142214985","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}