ChemRxiv最新文献

{"title":"Automated Membrane Characterization: In-situ Monitoring of the Permeate and Retentate Solutions using a 3D Printed Permeate Probe Device","authors":"Jonathan, Ouimet, Faraj, Al-Badani, Xinhong, Liu, Laurianne, Lair, Zachary, Muetzel, Alexander, Dowling, William, Phillip","doi":"10.26434/chemrxiv-2024-31fl1-v2","DOIUrl":"https://doi.org/10.26434/chemrxiv-2024-31fl1-v2","url":null,"abstract":"Self-driving laboratories and automated experiments can accelerate the design workflow and decrease errors associated with experiments that characterize membrane transport properties. Within this study, we use 3D printing to design a custom stirred cell that incorporates inline conductivity probes in the retentate and permeate streams. The probes provide a complete trajectory of the salt concentrations as they evolve over the course of an experiment. Here, automated diafiltration experiments are used to characterize the performance of commercial NF90 and NF270 polyamide membranes over a predetermined range of KCl concentrations from 1-100 mM. The measurements obtained by the inline conductivity probes are validated using offline post-experiment analyses. Compared to traditional filtration experiments, the probes decrease the amount of time required for an experimentalist to characterize membrane materials by more than 50× and increase the amount of information generated by 100×. Device design principles to address the physical constraints associated with making conductivity measurements in confined volumes are proposed. Overall, the device developed within this study provides a foundation to establish high-throughput, automated membrane characterization techniques.","PeriodicalId":9813,"journal":{"name":"ChemRxiv","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267245","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":"Long Molecular Wires and the Auto-ionization of Water","authors":"Yinan, Xu, Samuel, Varner, Yezhi, Jin, Gustavo, Pérez-Lemus, Joan, Montes de Oca, Zhen-Gang, Wang, Juan, de Pablo","doi":"10.26434/chemrxiv-2024-f9bv7","DOIUrl":"https://doi.org/10.26434/chemrxiv-2024-f9bv7","url":null,"abstract":"Water auto-ionization is critical in a wide range of chemical, biological, physical, and industrial processes. In this work, we describe a series of hitherto unknown collective molecular processes leading to auto-ionization. Specifically, by combining machine-learned interatomic potentials and spectral adaptive biasing force techniques, we determine the relevant free energy landscape of water auto-ionization. At ambient conditions, the free energy profile reveals two distinct saddle points, each leading to the formation of three- and four-member water wires. The wires feature an individual Zundel ion and a proton diffusion-like transition state, respectively. At elevated temperatures, the auto-ionization process exhibits a more concerted hydrogen transfer mechanism and reveals an alternative pathway involving the synchronous diffusion of Zundel ion pairs, with the ion pair corresponding to an energetic local minimum on the free energy surface. These findings help resolve long-standing conflicting views of the mechanism of water auto-ionization and provide new avenues for the study of proton behavior in different aqueous environments.","PeriodicalId":9813,"journal":{"name":"ChemRxiv","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267373","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 photothermal activation assisted synthesis, and orthogonal assembly of metal-organic-framework","authors":"Yossi, Weizmann, Aritra, Biswas, Nir, Lemcoff, Ofir, Shelonchik","doi":"10.26434/chemrxiv-2024-vmk13","DOIUrl":"https://doi.org/10.26434/chemrxiv-2024-vmk13","url":null,"abstract":"Temperature is a fundamental parameter in any chemical process, affecting reaction rates, selectivity, and more. Typically, chemists think of temperature as a homogeneous property, remaining unchanged throughout the reaction in space and time. Recently, photothermal materials have been emerging as an exciting tool opening new paths for innovative research, challenging the viewpoint described above. Herein, we develop a synthesis and in-situ assembly technique for metal-organic frameworks (MOFs) based on the distinct heterogeneous heating of photothermal materials under visible light. Notably, a simple cobalt chloride molecular complex was utilized as an efficient and stable light-to-heat converter for initial MOF formation. A thorough investigation of the assembly mechanism revealed the key role photothermal activation had in the formation of the superstructures. Finally, palladium nanoparticles (NP) were utilized as competing photothermal agents shedding light on the dynamics between different heat sources within a reaction and resulting in MOF-NP composites. This work highlights the versatility of the photothermal approach in the synthesis of advanced materials introducing a promising route to the micro/nano assembly of different materials.","PeriodicalId":9813,"journal":{"name":"ChemRxiv","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267382","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":"Hybrid synthesis of AMFC-derived amides using supported gold nanoparticles and acyl-coenzyme A ligases","authors":"Lucas, Bisel, Aurélie, Fossey-Jouenne, Richard, Martin, Jonathan, Bassut, Antoine, Lancien, Louis, Mouterde, Vivien, Herrscher, Muriel, Billamboz, Carine, Vergne-Vaxelaire, Rénato, Froidevaux, Anne, Zaparucha, Egon, Heuson","doi":"10.26434/chemrxiv-2024-2d7wr","DOIUrl":"https://doi.org/10.26434/chemrxiv-2024-2d7wr","url":null,"abstract":"By integrating different types of catalysts in the same system, hybrid catalysis emerges as an attractive and competitive approach. Within the framework of valorizing sustainably sourced bio-based products, we herein present a synthetic method for producing amides from alcohols and the bio-sourced 5-aminomethyl-2-furancarboxylic acid (AMFC). This approach utilizes supported gold metal nanoparticles as heterogeneous chemocatalysts, in conjunction with an acyl-coenzyme A ligase (ACL). By combining the actions of these catalysts, aliphatic mono- and di-alcohols are converted to the corresponding AMFC-derived amides with yields of up to 65% in aqueous buffer at 60 °C. This process requires only the addition of the enzyme and associated reactants in the same vessel for the second step in an one-pot/two-steps procedure.","PeriodicalId":9813,"journal":{"name":"ChemRxiv","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267237","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":"Photoswitching molecules functionalized with optical cycling centers provide a novel platform for studying chemical transformations in ultracold molecules","authors":"Paweł, Wójcik, Taras , Khvorost, Guanming , Lao, Guozhu, Zhu, Antonio, Macias Jr, Justin, Caram, Wesley, Campbell, Miguel, García-Garibay, Eric, Hudson, Anastassia , Alexandrova, Anna, Krylov","doi":"10.26434/chemrxiv-2024-l71cj","DOIUrl":"https://doi.org/10.26434/chemrxiv-2024-l71cj","url":null,"abstract":"A novel molecular structure that merges the fields of molecular optical cycling with molecular photoswitching is presented. It is based on a photoswitching molecule azobenzene functionalized with one and two CaO- groups, which can act as optical cycling centers (OCCs). This paper characterizes the electronic structure of the resulting model systems, focusing on three questions: (1) how the electronic states of the photoswitch are impacted by a functionalization with an OCC; (2) how the states of the OCC are impacted by the scaffold of the photoswitch; (3) whether the OCC can serve as spectroscopic probe of isomerization. The experimental feasibility of the proposed design and the advantages that organic synthesis can offer in fur- ther functionalization of the molecular scaffold are also discussed. This work brings into the field of molecular optical cycling a new dimension of chemical complexity, intrinsic only to polyatomic molecules.","PeriodicalId":9813,"journal":{"name":"ChemRxiv","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267381","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":"Design, Synthesis, and Optoelectronic Properties of π-Expanded Indoloindolizines.","authors":"Przemysław, Gaweł, Abhishek, Pareek, Muhammad Yasir , Mehboob, Maciej, Majdecki, Hubert, Szabat, Piotr, Połczyński, Cina, Foroutan-Nejad, Maja, Morawiak","doi":"10.26434/chemrxiv-2024-q9j9k","DOIUrl":"https://doi.org/10.26434/chemrxiv-2024-q9j9k","url":null,"abstract":"The development of stable and tunable polycyclic aromatic compounds (PACs) is crucial for advancing organic optoelectronics. Conventional polycyclic aromatic hydrocarbons (PAHs), such as acenes, often suffer from poor stability due to photooxidation and oligomerization, which are linked to their frontier molecular orbital energy levels. To address these limitations, we have designed and synthesized a new class of π-expanded indoloindolizines by merging indole and indolizine moieties into a single polycyclic framework. Guided by the Glidewell-Lloyd rule—which predicts that in fused polycyclic systems, larger rings lose aromaticity in favor of smaller ones—we achieved precise modulation of the electronic structure by controlling the aromaticity of specific rings. Benzannulation at targeted positions allowed fine-tuning of the HOMO-LUMO gap, leading to distinct shifts in optoelectronic properties. We developed a scalable synthetic protocol to produce a wide range of π-expanded derivatives. The structural, electronic, and optical properties of these compounds were extensively characterized. Single-crystal X-ray diffraction confirmed their molecular structure, while theoretical calculations provided insights into the observed experimental trends. These indoloindolizines exhibit vivid colors and fluorescence across the visible spectrum, and their enhanced stability against photooxidation compared to acenes makes them promising candidates for practical applications in optoelectronic devices. Reactivity studies demonstrated high regioselectivity in electrophilic substitutions, highlighting the indole-like behavior of these compounds and opening avenues for further functionalization. Overall, our work establishes indoloindolizines as a promising platform for the development of stable, tunable organic materials for optoelectronic applications. By leveraging rational molecular design guided by the Glidewell-Lloyd rule, we offer a new pathway for molecular design in organic electronics, potentially enhancing device performance and longevity.","PeriodicalId":9813,"journal":{"name":"ChemRxiv","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267371","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":"Phase Separation and Passive Diffusion of Perfluorooctane Sulfonic Acid (PFOS) in Multilamellar and Unilamellar Vesicles","authors":"Stephanie L., Wunder, Tutan Das, Aka, Thomas, Boller, Graham, Dobereiner","doi":"10.26434/chemrxiv-2024-2pdt3","DOIUrl":"https://doi.org/10.26434/chemrxiv-2024-2pdt3","url":null,"abstract":"Perfluorinated alkyl substances (PFAS) are important environmental hazards that enter microorganisms\u0000and animal tissues via their cellular membranes, where they bind to both proteins and lipids1. The\u0000interaction of a prevalent PFAS, perfluorooctane sulfonic acid (PFOS), with a model cell membrane\u0000composed of dipalmitoyl phosphatidylcholine (DPPC) was investigated as a function of molar ratio of\u0000DPPC/PFOS in both multilamellar vesicles (MLVs) and large unilamellar vesicles (LUVs). The PFOS was both\u0000prepared and incubated with the vesicles and its incorporation into the LUVs and MLVs was monitored by\u0000nano- differential scanning calorimetry (for phase transition temperatures, Tm) and by dynamic light\u0000scattering (DLS) or optical microscopy for size. For MLVs and LUVs prepared with PFOS, no pretransition\u0000was observed. The LUVs and MLVs remained intact for up to 30 days with sizes ~ 100nm for LUVs and ~\u000010-100 μm for MLVs. At DPPC/PFOS ~ 75/1 to 7.5/1, there was a single Tm, that decreased and broadened\u0000as the DPPC/PFOS molar ratio decreased, as previously observed.2 At higher PFOS concentrations,\u0000DPPC/PFOS < 5/1, two or three phase transitions were observed, with one Tm at a temperature close to\u0000that of the neat MLVs/LUVs and one at lower temperature. This was interpreted as phase separation into\u0000PFOS rich and PFOS poor domains. When MLVs were incubated with PFOS, both the main (Tm) and\u0000pretransition (Tpre), characteristic of neat DPPC, were observed, indicating the presence of bilayers with\u0000no incorporated PFOS. The intensity of Tm decreased with increased time, temperature (i.e. faster above\u0000than below Tm) and the external PFAS concentration, and Tpre increased (T = Tm - Tpre decreased).\u0000Concurrently, a phase transition in the MLVs at lower temperature was observed and disappeared with\u0000time. These results indicate that there was progressive penetration of the PFOS from the outer leaflets\u0000(that had incorporated PFOS) to the interior bilayers (that had no incorporated PFOS) of the MLVs, and by\u0000implication that there was passive diffusion of PFOS across (not just into) the DPPC bilayers, which\u0000occurred more quickly above than below Tm. While diffusion of PFOS across cellular membranes has\u0000previously been observed, this effect has been attributed to association with membrane proteins.","PeriodicalId":9813,"journal":{"name":"ChemRxiv","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267369","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":"Toward Ab initio Simulation of Operando Raman Spectroscopy: Application to Sulfur/Carbon Copolymer Cathodes in Li-S Batteries","authors":"Rana , Kiani, Huiying , Sheng, Timo, Held, Oliver , Löhmann, Sebastian , Risse, Pouya, Partovi-Azar, Daniel, Sebastiani","doi":"10.26434/chemrxiv-2024-q6ssd","DOIUrl":"https://doi.org/10.26434/chemrxiv-2024-q6ssd","url":null,"abstract":"Sulfur/carbon copolymers have emerged as a promising alternative for conventional crystalline sulfur cathodes for lithium-sulfur batteries. Among these, sulfur–n–1,3– diisopropenylbenzene (S/DIB) copolymers, which present a network of DIB molecules interconnected via sulfur chains, have particularly shown a good performance and, there- fore, have been under intensive experimental and theoretical investigations. However, their structural complexity and flexibility have hindered a clear understanding of their structural evolution during redox reactions at an atomistic level. Here, by performing state-of-the-art finite-temperature ab initio Raman spectroscopy simulations, we inves- tigate the spectral fingerprints of S/DIB copolymers during consecutive reactions with lithium. We discuss in detail Raman spectral changes in particular frequency ranges which are common in S/DIB copolymers having short sulfur chains and those consisting of longer ones. We also highlight those distinctive spectroscopic fingerprints specific to local S/DIB structures containing only short or long sulfur chains. This distinction could serve to help distinguish between them experimentally. Our theoretically predicted results are in a good agreement with experimental Raman measurements on coin cells at different discharge stages. This work represents, for the first time, an attempt to compute operando Raman spectra using quantum-chemical calculations and provides a guideline for Raman spectral changes of arbitrary electrodes during the discharge.","PeriodicalId":9813,"journal":{"name":"ChemRxiv","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267368","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":"An Efficient RI-MP2 Algorithm for Distributed Many-GPU Architectures","authors":"Giuseppe Maria Junior, Barca, Calum, Snowdon","doi":"10.26434/chemrxiv-2024-9091h-v2","DOIUrl":"https://doi.org/10.26434/chemrxiv-2024-9091h-v2","url":null,"abstract":"Second-order Møller-Plesset perturbation theory (MP2) using the Resolution of the Identity approximation (RI-MP2) is a widely used method for computing molecular energies beyond the Hartree-Fock mean-field approximation. However, its high computational cost and lack of efficient algorithms for modern supercomputing architectures limit its applicability to large molecules. In this paper, we present the first distributed-memory many-GPU RI-MP2 algorithm explicitly designed to utilize hundreds of GPU accelerators for every step of the computation. Our novel algorithm achieves near-peak performance on GPU-based supercomputers through the development of a distributed memory algorithm for forming RI-MP2 intermediate tensors with zero inter-node communication, except for a single O(N^2) asynchronous broadcast, and a distributed memory algorithm for the O(N^5) energy reduction step, capable of sustaining near-peak performance on clusters with several hundred GPUs. Comparative analysis shows our implementation outperforms state-of-the-art quantum chemistry software by over 3.5 times in speed while achieving an eightfold reduction in computational power consumption. Benchmarking on the Perlmutter supercomputer, our algorithm achieves 11.8 PFLOP/s (83% of peak performance) performing and the RI-MP2 energy calculation on a 314-water cluster with 7,850 primary and 30,144 auxiliary basis functions in 4 minutes on 180 nodes and 720 A100 GPUs. This performance represents a substantial improvement over traditional CPU-based methods, demonstrating significant time-to-solution and power consumption benefits of leveraging modern GPU-accelerated computing environments for quantum chemistry calculations.","PeriodicalId":9813,"journal":{"name":"ChemRxiv","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267239","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":"Fe-Catalyzed Structurally Divergent γ-Polyhaloalkylation of Si- loxydienes","authors":"Justin, Mohr, Douglas, Yarbrough, Brian, Osei-Badu, Cole, Wagner, Kayla, Storme, Sebastian, Marquez R.","doi":"10.26434/chemrxiv-2024-78vqn","DOIUrl":"https://doi.org/10.26434/chemrxiv-2024-78vqn","url":null,"abstract":"Regioselective γ-polyhaloalkylation is achieved using tetrahalomethanes or α,α,α-trihaloalkyl compounds and siloxydienes via Fe(II) catalysis. A range of siloxydienes are functionalized in good yield and high stereoselectivity under mild reaction conditions. Structural divergence is observed as either haloalkylated or haloalkenylated products are formed based on substitution pattern of the siloxydiene. The halogenated products show utility in further synthetic transformations selec- tive reduction and cross coupling reactions.","PeriodicalId":9813,"journal":{"name":"ChemRxiv","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267251","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}