jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Shama Perween | Kerstin Wissel | Zsolt Dallos | Morten Weiß | Yuji Ikeda | Sami Vasala | Sabine Strobel | Peter Schuetzenduebe | Pascal M. Jeschenko | Ute Kolb | Roland Marschall | Blazej Grabowski | Pieter Glatzel
Source: ChemRxiv (preprint, 2023-08-31)
Field: Materials Science — Materials Chemistry

Topochemical Fluorination of LaBaInO4 to LaBaInO3F2, their Optical Characterization and Photocatalytic Activities for Hydrogen Evolution We report on a non-oxidative topochemical route for the synthesis of a novel indate-based oxyfluoride, LaBaInO3F2, using a low-temperature reaction of Ruddlesden–Popper-type LaBaInO4 with polyvinylidene difluoride as a fluorinating agent. The reaction involves the replacement of oxide ions with fluoride ions as well as the insertion of fluoride ions at interstitial sites. From the characterization via powder X-ray diffraction (PXRD) and Rietveld analysis as well as automated electron diffraction tomography (ADT) it is deduced that the fluorination results in a symmetry lowering from I4/mmm (139) to monoclinic C2/c (15) with an expansion perpendicular to the perovskite layers and a strong tilting of the octahedra in the ab plane. Disorder of the anions on the apical and the interstitial sites seems to be favored. The most stable configuration for the anion ordering is estimated based on an evaluation of bond distances from the ADT measurements via bond valence sums (BVSs). The observed disordering of the anions in the oxyfluoride results in changes of the optical properties and thus shows that the topochemical anion modification can present a viable route to alter optical properties. Partial densities of states (PDOSs) obtained from ab initio density functional theory (DFT) calculations reveal a bandgap modification upon fluoride-ion introduction which originates from the presence of the oxide anions on the interstitial sites. The photocatalytic performance of the oxide and oxyfluoride shows that both of the materials are photocatalytically active for hydrogen (H2) evolution. Density functional theory ; Fluoride ; Oxide ; Rietveld refinement ; Ion ; Crystallography ; Photocatalysis ; Ab initio ; Powder diffraction ; Materials science ; Valence (chemistry) ; Octahedron ; Monoclinic crystal system ; Chemistry ; Inorganic chemistry ; Crystal structure ; Physical chemistry ; Computational chemistry ; Catalysis ; Organic chemistry Luminescence Properties of Advanced Materials ; Inorganic Fluorides and Related Compounds ; Advanced Photocatalysis Techniques
Authors: Ilia Kochetygov | Jocelyn Roth | Jordi Espín | Sophia Pache | Anita Justin | Till Schertenleib | Nazanin Taheri | Dmitry Chernyshov | Wendy L. Queen
Source: Angewandte Chemie (article, 2023-02-15)
Field: Chemistry — Inorganic Chemistry

A Simple, Transition Metal Catalyst‐Free Method for the Design of Complex Organic Building Blocks Used to Construct Porous Metal–Organic Frameworks Abstract The design of metal–organic frameworks (MOFs) having large pore sizes and volumes often requires the use of complex organic ligands, currently synthesized using costly and time‐consuming palladium‐catalyzed coupling chemistry. Thus, in the present work, a new strategy for ligand design is reported, where piperazine and dihydrophenazine units are used as substitutes for benzene rings, which are the basic building block of most MOF ligands. This chemistry, which is based on simple, nucleophilic aromatic substitution (S N Ar) reactions, is used for the transition metal catalyst‐free construction of 21 new, carboxylate‐based ligands with varying sizes, shapes, and denticity and 15 linear di‐ and tetra‐nitriles. Moreover, to demonstrate the utility of the ligands as building blocks, 16 new structurally diverse MOFs having surface areas up to 3100 m 2 g −1 were also synthesized. Transition metal ; Denticity ; Chemistry ; Catalysis ; Metal-organic framework ; Palladium ; Ligand (biochemistry) ; Piperazine ; Combinatorial chemistry ; Nucleophilic aromatic substitution ; Nucleophile ; Organic chemistry ; Metal ; Nucleophilic substitution ; Adsorption Metal-Organic Frameworks: Synthesis and Applications ; Magnetism in coordination complexes ; Dendrimers and Hyperbranched Polymers
Authors: Jana Pisk | Sara Marijan | Teodoro Klaser | Petr Mošner | Ladislav Koudelka | Dominique Agustin | Željko Skoko | Luka Pavić
Source: Journal of Non-Crystalline Solids (article, 2023-12-23)
Field: Materials Science — Ceramics and Composites

Peculiar catalytic properties of oxide glass-(ceramics) in epoxidation reactions Catalysis ; Cyclooctene ; Ceramic ; Epoxide ; Materials science ; Oxide ; Vanadium ; Decane ; Molar ratio ; Electrical resistivity and conductivity ; Chemical engineering ; Nuclear chemistry ; Chemistry ; Inorganic chemistry ; Organic chemistry ; Composite material ; Metallurgy Glass properties and applications ; Catalysis and Oxidation Reactions ; Nuclear materials and radiation effects
Authors: Timur Yumalin | R. B. Salikhov | Lyaysan R. Latypova | Timur Salikhov | А. Г. Мустафин | Ildus F. Sharafullin
Source: Preprints.org (preprint, 2023-11-23)
Field: Materials Science — Polymers and Plastics

Fluorescence of Polyanilines and Photoconductivity of Thin Films Based on Their Copolymers Polyanilines are a class of conductive polymers that have attracted significant interest in the field of organic electronics due to their unique properties. In this article, the fluorescence spectroscopy and photovoltaic properties of polyaniline-based thin films and copolymers are investigated. The study focuses on understanding the relationship between the composition and structure of polyanilines and their optical and electrical properties. The article discusses the results of experiments on the photoluminescent properties of S1-S9 copolymers in a DMSO solution and of thin-film photoresistors based on polyanilines. The findings reveal that the photovoltaic properties of the thin films depend on the conditions of their fabrication and their surface morphology. The solubility of polyanilines is excellent, making the production of electronic components compatible with modern printing technologies in organic electronics. The work also points out that the photoconductivity of polyanilines can be improved by incorporation of additional molecular groups into the polymer matrix. Overall, this study sheds light on the potential of polyanilines as promising materials for organic electronics and provides insights into how their properties can be optimized for specific applications. Materials science ; Polyaniline ; Organic electronics ; Thin film ; Conductive polymer ; Photoconductivity ; Copolymer ; Nanotechnology ; Polymer ; Fabrication ; Electronics ; Optoelectronics ; Chemistry ; Composite material ; Transistor ; Electrical engineering ; Polymerization Conducting polymers and applications ; Semiconductor materials and interfaces ; Polymer Nanocomposite Synthesis and Irradiation
Authors: Beihang Yu | Boyce S. Chang | Whitney S. Loo | Scott Dhuey | Padraic O’Reilly | Paul D. Ashby | Michael D. Connolly | Grigory Tikhomirov | Ronald N. Zuckermann | Ricardo Ruiz
Source: ChemRxiv (preprint, 2023-10-16)
Field: Materials Science — Surfaces, Coatings and Films

Nanopatterned Monolayers of Bioinspired, Sequence-Defined Polypeptoid Brushes for Semiconductor/Bio Interfaces The ability to control and manipulate semiconductor/bio interfaces is key to enable biological nanofabrication pathways and new bioelectronic devices. Conventional surface functionalization strategies like self-assembled monolayers (SAMs) provide a limited level of customization for such interfaces. Polymer brushes offer a wider range of chemistries, but choices that maintain compatibility with both lithographic patterning and biological systems are limited. Here we developed a class of bioinspired, sequence-defined polymers, polypeptoids, as tailored polymer brushes for surface modification of semiconductor substrates. Polypeptoids with a terminal hydroxyl (–OH) group are designed and synthesized to enable efficient melt grafting onto the native oxide layer of Si substrates, forming ~1 nm thick monolayers. By programming monomer chemistry, the polypeptoid brush platform enables efficient and versatile surface modification in surface energy, passivation to preferential attachment of biomolecules, and specific binding of biomolecules. The polypeptoid brush monolayers are compatible with electron-beam lithographic patterning and maintain their chemical characteristics after exposure to the harsh conditions of the lithographic patterning workflow. Highly precise, well-defined chemical contrast nanopatterns consisting of two polymer brushes are designed and generated with a passivation background and active binding regions to achieve selective immobilization of biomacromolecules including DNA origami and streptavidin at length scales defined by electron-beam lithography. This surface modification strategy with bioinspired, sequence-defined polypeptoid brushes enables monomer- level control over surface properties with a large parameter space of monomer chemistry and sequence, and therefore is a highly versatile platform to precisely engineer semiconductor/bio interfaces for bioelectronics applications. Nanotechnology ; Monolayer ; Biomolecule ; Materials science ; Lithography ; Polymer ; Passivation ; Surface modification ; Polymer brush ; Nanolithography ; Self-assembled monolayer ; Chemistry ; Layer (electronics) ; Fabrication ; Polymerization ; Optoelectronics Polymer Surface Interaction Studies ; Nanofabrication and Lithography Techniques ; Molecular Junctions and Nanostructures
Authors: Beihang Yu | Boyce S. Chang | Whitney S. Loo | Scott Dhuey | Padraic O’Reilly | Paul D. Ashby | Michael D. Connolly | Grigory Tikhomirov | Ronald N. Zuckermann | Ricardo Ruiz
Source: ChemRxiv (preprint, 2023-10-19)
Field: Materials Science — Surfaces, Coatings and Films

Nanopatterned Monolayers of Bioinspired, Sequence-Defined Polypeptoid Brushes for Semiconductor/Bio Interfaces The ability to control and manipulate semiconductor/bio interfaces is essential to enable biological nanofabrication pathways and new bioelectronic devices. Traditional surface functionalization methods, like self-assembled monolayers (SAMs), provide limited customization for these interfaces. Polymer brushes offer a wider range of chemistries, but choices that maintain compatibility with both lithographic patterning and biological systems are scarce. Here we developed a class of bioinspired, sequence-defined polymers, i.e., polypeptoids, as tailored polymer brushes for surface modification of semiconductor substrates. Polypeptoids featuring a terminal hydroxyl (–OH) group are designed and synthesized for efficient melt grafting onto the native oxide layer of Si substrates, forming ultrathin (~1 nm) monolayers. By programming monomer chemistry, our polypeptoid brush platform offers versatile surface modification, including adjustments to surface energy, passivation, preferential biomolecule attachment, and specific biomolecule binding. Importantly, the polypeptoid brush monolayers remain compatible with electron-beam lithographic patterning and retain their chemical characteristics even under harsh lithographic conditions. Electron-beam lithography is used over polypeptoid brushes to generate highly precise, binary nanoscale patterns with localized functionality for the selective immobilization (or passivation) of biomacromolecules such as DNA origami or streptavidin onto addressable arrays. This surface modification strategy with bioinspired, sequence-defined polypeptoid brushes enables monomer-level control over surface properties with a large parameter space of monomer chemistry and sequence, and therefore is a highly versatile platform to precisely engineer semiconductor/bio interfaces for bioelectronics applications. Nanotechnology ; Monolayer ; Biomolecule ; Materials science ; Lithography ; Passivation ; Surface modification ; Polymer ; Self-assembled monolayer ; Polymer brush ; Chemistry ; Layer (electronics) ; Optoelectronics ; Polymerization Polymer Surface Interaction Studies ; Nanofabrication and Lithography Techniques ; Molecular Junctions and Nanostructures
Authors: Nicolò Tampellini | Brandon Q. Mercado | Scott J. Miller
Source: ChemRxiv (preprint, 2023-12-20)
Field: Chemistry — Organic Chemistry

Scaffold-Oriented Asymmetric Catalysis: Conformational Modulation of Transition State Multivalency during a Catalyst-Controlled Assembly of a Pharmaceutically Relevant Atropisomer A new class of superbasic, bifunctional peptidyl guanidine catalysts is presented, which enable the organocatalytic, atroposelective synthesis of axially chiral quinazolinediones. Computational modeling unveiled the conformational modulation of the catalyst by a novel phenyl urea N-cap, that shape-shifts the structure into the active, folded state. A previously unanticipated noncovalent interaction involving a difluoroacetamide acting as a hybrid mono- or bidentate hydrogen bond donor emerged as a decisive control element inducing atroposelectivity. These discoveries spurred from a scaffold-oriented project inspired from a fascinating investigational BTK inhibitor featuring two stable chiral axes, and relies on a mechanistic framework that was foreign to the extant lexicon of asymmetric catalysis. Chemistry ; Catalysis ; Hydrogen bond ; Guanidine ; Scaffold ; Atropisomer ; Bifunctional ; Chirality (physics) ; Combinatorial chemistry ; Denticity ; Stereochemistry ; Crystallography ; Organic chemistry ; Molecule ; Crystal structure Axial and Atropisomeric Chirality Synthesis ; Molecular spectroscopy and chirality ; Asymmetric Synthesis and Catalysis
Authors: Lucija Vujević | Bahar Karadeniz | Nikola Cindro | Andraž Krajnc | Gregor Mali | Stanislav M. Avdoshenko | Alexey A. Popov | Dijana Žilić | Krunoslav Užarević | Marina Kveder
Source: ChemRxiv (preprint, 2023-04-28)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Improving the molecular spin qubit performance in multivariate zirconium MOF hybrids by mechanochemical dilution and fullerene encapsulation Enlarging the quantum coherence times and gaining control over quantum effects in real systems are fundamental for developing of quantum technologies. Molecular electron spin qubits are particularly promising candidates for the realization of quantum information processing due to their modularity and tunability, but there is a constant search for tools to increase their quantum coherence times. Here we present how mechanochemical dilution of active spin qubits in the diamagnetic zirconium-MOF matrix, in synergy with controlled encapsulation of fullerene guest, results in a significant increase in relaxation times and better qubit performances of the moderately porous MOF qubit array candidate. 10% diluted copper(II)-porphyrins as potential molecular spin qubits were incorporated in polymorphic PCN-223 and MOF- 525. Spin properties of this hybrid molecular spin qubit frameworks were studied by continuous-wave and pulse electron spin resonance/electron paramagnetic resonance (ESR/EPR) spectroscopy, showing that both spin-lattice and phase memory electron spin relaxation times, T1 and Tm, respectively, increased by the encapsulation of fullerene molecules into the MOF matrix. Specifically, PCN-223 with a larger filling of fullerene shows better performance in both relaxation times compared with the previously surpassing MOF-525 molecular spin qubit framework. Qubit ; Electron paramagnetic resonance ; Fullerene ; Spin engineering ; Chemical physics ; Materials science ; Chemistry ; Quantum ; Nanotechnology ; Condensed matter physics ; Electron ; Spin polarization ; Nuclear magnetic resonance ; Physics ; Quantum mechanics Magnetism in coordination complexes ; Electron Spin Resonance Studies ; Organic and Molecular Conductors Research
Authors: Emily Schroeder | Yue Fu | Jed Kim | Wentan Liu | Peng Liu | Jennifer M. Schomaker
Source: ChemRxiv (preprint, 2023-08-09)
Field: Chemistry — Organic Chemistry

Scope and computational insights into enantioselective C–H amination through silver-catalyzed nitrene transfer Chiral, non-racemic amines and amino alcohols are prevalent in drugs, bioactive natural products and ligands for transi-tion metal catalysis. Asymmetric nitrene transfer is an efficient and powerful strategy to prepare enantioenriched amines from abundant C–H bonds; however, there is a continued need for general and inexpensive transition metal catalysts sup-ported by easily tunable ligands. Herein, we report silver salts ligated to an unusual bis(oxazoline) (BOX) ligand, readily accessible through a modular synthetic approach, catalyze site- and enantioselective nitrene transfers into benzylic, al-lylic and unactivated C–H bonds of carbamate esters. The resulting 1,3-aminoalcohol building blocks are delivered in good yields and moderate-to-excellent enantioselectivities up to 99%. Computational models were employed to rational-ize the observed stereochemical outcomes and set the stage for the predictive design of second-generation silver cata-lysts. These in-depth computational investigations implicate a complex combination of features in promoting enantiose-lectivity, including substrate distortion from a square-planar geometry at silver and stabilizing C–H/π interactions be-tween ligand and substrate. Careful analyses of the enantiodetermining transition states employing diverse substrates revealed the dominant factors controlling selectivity for each substrate class, thus enabling the rational design of ligand and catalyst combinations that furnish a broader scope of chemo-, site- and enantioselective C–H bond aminations. Enantioselective synthesis ; Nitrene ; Amination ; Chemistry ; Combinatorial chemistry ; Ligand (biochemistry) ; Substrate (aquarium) ; Rational design ; Catalysis ; Organocatalysis ; Stereochemistry ; Organic chemistry ; Nanotechnology ; Materials science Synthesis and Catalytic Reactions ; Catalytic C–H Functionalization Methods ; Asymmetric Hydrogenation and Catalysis
Authors: Serena Fantasia | Björn Bartels | Fritz Bliss | Fritz Koch | Michelangelo Scalone | Daniel C. Spiess | Markus Steiner | Shaoning Wang | Kurt Püntener
Source: Helvetica Chimica Acta (article, 2023-09-04)
Field: Chemistry — Organic Chemistry

A Streamlined, Safe and Sustainable Process for Gemlapodect Abstract The research efforts to attain a suitable process for the timely delivery of Gemlapodect for initial toxicological and phase 1/2 clinical studies are described. The original discovery chemistry route was hampered by considerable safety issues and low overall yield. The safety issues were solved by the introduction of a copper‐catalyzed oxidative cyclization while a novel process for the synthesis of the pyrazole building block as well as the implementation of a palladium‐catalyzed coupling between the pyrazole amide and the bromo‐triazolopyridine scaffolds contributed to improve the route efficiency. Overall, a safe and sustainable process was attained that allowed the production of up to 19.2 kg of drug substance with a reduced number of steps and an increased overall yield. Chemistry ; Pyrazole ; Yield (engineering) ; Combinatorial chemistry ; Process (computing) ; Amide ; Biochemical engineering ; Organic chemistry ; Computer science ; Engineering Catalytic C–H Functionalization Methods ; Nanomaterials for catalytic reactions ; Synthesis and Biological Evaluation
Authors: Kristaps Saršu̅ns | Artis Kons | Toms Rekis | Agris Be̅rziņš
Source: ChemRxiv (preprint, 2023-07-17)
Field: Materials Science — Materials Chemistry

Experimental and Computational Study of Solid Solutions Formed between Substituted Nitrobenzoic Acids We present an experimental and computational study of solid solution formation in binary systems of substituted nitrobenzoic acids. Different isomers with methyl group, hydroxyl group, and chlorine substituents are studied. We show that the solid solution formation likelihood evaluated based on the observed solubility limit is notably affected by both - the exchanged functional groups and the location of the substituents in the molecular structure. This demonstrates that the component solubility limit strongly depends on the intermolecular interactions present in the crystal structure and altered by the molecule replacement. Solid solutions form in all of the studied crystalline phases. Component solubility limits from around 5% up to 50% were observed. The obtained results indicated that the calculated intermolecular interaction energy change by the functional group replacement does not allow to rationalize the experimentally observed solubilities neither considering the molecules adjacent to the replace group nor all the molecules within a 15 Å radius. The relative energy of the experimental structures and isostructural phases obtained from the computationally generated structure landscapes calculated at the level providing accurate energy ranking was found to be mostly consistent with the experimentally observed component solubilities. Isostructural ; Intermolecular force ; Solubility ; Molecule ; Chemistry ; Component (thermodynamics) ; Crystal structure ; Thermodynamics ; Solid solution ; Group (periodic table) ; Computational chemistry ; Crystallography ; Physical chemistry ; Organic chemistry ; Physics Crystallization and Solubility Studies ; Chemical and Physical Properties in Aqueous Solutions ; Crystallography and molecular interactions
Authors: Alec Coles | Oskar G. Wood | Chris S. Hawes
Source: Journal of the Serbian Chemical Society (article, 2023-01-01)
Field: Chemistry — Inorganic Chemistry

Ligands containing 7-azaindole functionality for inner-sphere hydrogen bonding: Structural and photophysical investigations The synthesis, structural analysis and spectroscopic characterisation of three new 7-azaindole ligands is reported, alongside a novel 7-azaindole derived coordination polymer, with the aim of identifying new bridging ligands containing inner-sphere hydrogen bond donor functionality. Structural characterisation shows that the 7-azaindole hydrogen bond donor ability is significantly stronger in the hydrazone and imine species 1 and 2 compared to the amine 3, with the opposite trend evident in their hydrogen bond acceptor character. These findings are mirrored by the fluorescence spectroscopy results which show bimodal emission, characteristic of multiple emissive species related by proton transfer, is only evident in the amine species and not the more acidic imines. The polymeric copper(II) complex of the hydrazone ligand 1 shows the anticipated inner-sphere hydrogen bonding with a similar donor strength to that observed in the free ligand, which leads to deformation in the remainder of the coordination sphere. These results show the untapped versatility of the 7-azaindole functional group as a building block for ligands in coordination polymers and other multinuclear assemblies, with the potential for both stabilisation through hydrogen bonding and interesting photophysical properties. Hydrogen bond ; Coordination sphere ; Chemistry ; Imine ; Ligand (biochemistry) ; Acceptor ; Amine gas treating ; Photochemistry ; Fluorescence ; Polymer ; Crystallography ; Molecule ; Combinatorial chemistry ; Crystal structure ; Organic chemistry ; Catalysis Metal-Organic Frameworks: Synthesis and Applications ; Metal complexes synthesis and properties ; Magnetism in coordination complexes