jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Jannik Junge | Tobias A. Engesser | Jan Krahmer | Christian Näther | Felix Tuczek
Source: Zeitschrift für anorganische und allgemeine Chemie (article, 2021-01-16)
Field: Chemistry — Inorganic Chemistry

Rhodium(III) and Ruthenium(II) Complexes with a Pentadentate Tetrapodal Phosphine Ligand Abstract Rhodium(III) and ruthenium(II) complexes supported by a pentadentate tetrapodal ( pentaPod ) phosphine ligand are synthesized through abstraction of one chloride ligand from initially obtained κ 4 ‐ pentaPod coordinated dichloro complexes [MCl 2 ( κ 4 ‐P 2 Me PP 2 Ph )] +/0 (M=Rh(III), Ru(II)) with alkali salts of weakly coordinating anions. While for the rhodium κ 5 ‐ pentaPod complex the remaining, axial chloride ligand could not be replaced by di‐ or triatomic ligands, in case of ruthenium the complexes [Ru(CN)( κ 5 ‐P 2 Me PP 2 Ph ]Al(pftb) 4 ( 5 ) and [Ru(N 3 )( κ 5 ‐P 2 Me PP 2 Ph ]Al(pftb) 4 ( 6 ) could be generated through ligand exchange. By comparison of NMR parameters and employing DFT calculations, additional insights into the electronic influence of different ligands (i. e., Cl − , CN − , N 3 − ) could be gained. Ruthenium ; Rhodium ; Chemistry ; Ligand (biochemistry) ; Phosphine ; Chloride ; Medicinal chemistry ; Inorganic chemistry ; Polymer chemistry ; Stereochemistry ; Organic chemistry ; Catalysis Asymmetric Hydrogenation and Catalysis ; Catalytic C–H Functionalization Methods ; Organometallic Complex Synthesis and Catalysis
Authors: Ilaria D’Auria | Zeinab Saki | Claudio Pellecchia
Source: Macromol—A Journal of Macromolecular Research (article, 2021-05-07)
Field: Chemistry — Organic Chemistry

Iminopyridine Ni(II) Catalysts Affording Oily Hyperbranched Ethylene Oligomers and/or Crystalline Polyethylenes Depending on the Reaction Conditions: Possible Role of In Situ Catalyst Structure Modifications Nickel-based ethylene polymerization catalysts have unique features, being able to produce macromolecules with a variable content of branches, resulting in polymers ranging from semicrystalline plastics to elastomers to hyperbranched amorphous waxes and oils. In addition to Brookhart’s α-diimine catalysts, iminopyridine Ni(II) complexes are among the most investigated systems. We report that Ni(II) complexes bearing aryliminopyridine ligands with bulky substituents both at the imino moiety and in the 6-position of pyridine afford either hyperbranched low molecular weight polyethylene oils or prevailingly linear crystalline polyethylenes or both, depending on the ligand structure and the reaction conditions. The formation of multiple active species in situ is suggested by analysis of the post-polymerization catalyst residues, showing the partial reduction of the imino function. Some related arylaminopyridine Ni(II) complexes were also synthesized and tested, showing a peculiar behavior, i.e., the number of branches of the produced polyethylenes increases while ethylene pressure increases. Polymer chemistry ; Catalysis ; Polyethylene ; Ethylene ; Polymerization ; Diimine ; Polymer ; Chemistry ; Materials science ; Macromolecule ; Organic chemistry Organometallic Complex Synthesis and Catalysis ; Synthetic Organic Chemistry Methods ; Dendrimers and Hyperbranched Polymers
Authors: Freshsya Zata Lini | Dhanang Edy Pratama | Tu Lee
Source: Crystals (article, 2021-07-12)
Field: Materials Science — Materials Chemistry

Co-Crystallization Kinetics of 2:1 Benzoic Acid–Sodium Benzoate Co-Crystal: The Effect of Templating Molecules in a Solution The addition of dissolved templating molecules in crystallization will create “supramolecular assemblies” within the solution, serving as “anchor points” for the solute molecules to nucleate and grow. In this work, nucleation and crystal growth kinetics of 2:1 benzoic acid (HBz)–sodium benzoate (NaBz) co-crystallization with or without templates in a solution were analyzed by monitoring the concentration of the mother liquor during cooling crystallization. The results showed that the addition of the dissolved 2:1 or 1:1 HBz–NaBz co-crystals as templating molecules could reduce the critical free energy barrier of 2:1 HBz–NaBz co-crystal during its nucleation, but did not significantly affect the order of crystal growth rate. On the other hand, the critical free energy barrier of the nucleation process was increased if dissolved NaBz was used as a templating molecule, while a significant rise in the order of crystal growth rate occurred. The crystal habit obtained from the NaBz-templated system was needle-like, suggesting that sodium–sodium coordination chains of NaBz supramolecular assemblies in the solution phase were responsible for creating elongated crystals. Conversely, a large prismatic crystal habit found in non-templated and 2:1 and 1:1 HBz–NaBz co-crystal-templated systems implied that those templating molecules formed sparsely interconnected supramolecular assemblies in the solution phase. Crystallization ; Nucleation ; Supramolecular chemistry ; Benzoic acid ; Crystal habit ; Crystal (programming language) ; Crystallography ; Crystal growth ; Molecule ; Phase (matter) ; Materials science ; Chemistry ; Chemical engineering ; Crystal structure ; Organic chemistry Crystallization and Solubility Studies ; Crystallography and molecular interactions ; Enzyme Structure and Function
Authors: Jannatul Ferdous | Sarkar MA Kawsar
Source: The Chittagong University Journal of Science (article, 2021-06-22)
Field: Chemistry — Organic Chemistry

Thermochemical, Molecular Docking and ADMET Studies of Some Methyl α-D-Glucopyranoside Derivatives In this study, methyl α-D-glucopyranoside and its modified derivatives were optimized by employing density functional theory (DFT) with B3LYP/3-21G level theory to explore their structural and thermodynamic properties. Electronic energies, enthalpies, Gibbs free energies, dipole moments, Highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gaps, the density of states (DOS) and molecular electrostatic potential (MEP) of these modified compounds were found optimal in the subsequent analysis. Molecular docking has been performed against potential inhibitors of the Bacillus subtilis Obg protein (PDB: 1LNZ) to search the binding affinity and mode(s) of six compounds that have significant antibacterial and antifungal activities. It was found that the selected glucopyranoside derivatives have strong interactions mainly with Arg236 and Arg238 residues of the Bacillus subtilis Obg protein, and the molecules were surrounded by other active site residues like Lys156, Pro91, and Glu333. An absorption, distribution, metabolism, excretion, and toxicity (ADMET) calculation reveals that the modified derivatives are less toxic and have improved pharmacokinetic features over the parent drug. This computational investigation showed that these methyl α-D-glucopyranoside derivatives might be used as potential inhibitors against the promising antibacterial and antifungal activities for future studies. The Chittagong Univ. J. Sci. 42(1): 58-83, 2020 HOMO/LUMO ; Chemistry ; Density functional theory ; Protein Data Bank (RCSB PDB) ; Docking (animal) ; Bacillus subtilis ; Computational chemistry ; Molecular orbital ; Molecular model ; Molecule ; Stereochemistry ; Organic chemistry ; Biology Free Radicals and Antioxidants ; Nonlinear Optical Materials Research ; Synthesis and biological activity
Authors: Kateřina Hrůzová | Λεωνίδας Μάτσακας | Anthi Karnaouri | Fredrik Norén | Ulrika Rova | Paul Christakopoulos
Source: Biotechnology for Biofuels (article, 2021-01-28)
Field: Materials Science — Biomaterials

Valorization of outer tunic of the marine filter feeder Ciona intestinalis towards the production of second-generation biofuel and prebiotic oligosaccharides The utilisation of tunicate biomass offers an eco-friendly and sustainable alternative for value-added biofuels and chemicals. The cultivation of tunicate biomass in shallow coastal sea improves the quality of the water and ensures sustainable production of fish feed. Moreover, there is no competition for arable land, which leaves the latter available for food and feed production. Tunicate ; Biofuel ; Biomass (ecology) ; Biorefinery ; Ethanol fuel ; Ciona intestinalis ; Biohydrogen ; Chemistry ; Xylose ; Food science ; Pulp and paper industry ; Botany ; Biotechnology ; Biology ; Fermentation ; Agronomy ; Ecology ; Biochemistry ; Hydrogen production ; Engineering biodegradable polymer synthesis and properties ; Biodiesel Production and Applications ; Biofuel production and bioconversion
Authors: Ben. J. Tickner | Yulia Borozdina | Simon B. Duckett | Goran Angelovski
Source: Dalton Transactions (article, 2021-01-01)
Field: Chemistry — Spectroscopy

Exploring the hyperpolarisation of EGTA-based ligands using SABRE The design of molecules whose magnetic resonance (MR) signals report on their biological environment is receiving attention as a route to non-invasive functional MR. Hyperpolarisation techniques improve the sensitivity of MR and enable real time low concentration MR imaging, allowing for the development of novel functional imaging methodologies. In this work, we report on the synthesis of a series of EGTA-derived molecules (EGTA - ethylene glycol-bis(2-aminoethylether)-N,N,N',N'-tetraacetic acid), whose core structures are known to bind biologically relevant metal ions in vivo, in addition to pyridyl rings that allow reversible ligation to an iridium dihydride complex. Consequently, they are amenable to hyperpolarisation through the parahydrogen-based signal amplification by reversible exchange (SABRE) process. We investigate how the proximity of EGTA and pyridine units, and the identity of the linker group, affect the SABRE hyperpolarisation attained for each agent. We also describe the effect of catalyst identity and co-ligand presence on these measurements and can achieve <sup>1</sup>H NMR signal enhancements of up to 160-fold. We rationalise these results to suggest the design elements needed for probes amenable to SABRE hyperpolarisation whose MR signals might in the future report on the presence of metal ions. EGTA ; Chemistry ; Ligand (biochemistry) ; Molecule ; Linker ; Combinatorial chemistry ; Iridium ; Stereochemistry ; Catalysis ; Organic chemistry ; Calcium ; Receptor ; Biochemistry Advanced NMR Techniques and Applications ; Solid-state spectroscopy and crystallography ; Atomic and Subatomic Physics Research
Authors: Jan Fait | M. Varga | Karel Hruška | Alexander Kromka | Bohuslav Rezek | Lukáš Ondič
Source: Nanophotonics (article, 2021-09-16)
Field: Materials Science — Materials Chemistry

Spectral tuning of diamond photonic crystal slabs by deposition of a thin layer with silicon vacancy centers Abstract The controlled extraction of light from diamond optical color centers is essential for their practical prospective applications as single photon sources in quantum communications and as biomedical sensors in biosensing. Photonic crystal (PhC) structures can be employed to enhance the collection efficiency from these centers by directing the extracted light towards the detector. However, PhCs must be fabricated with nanoscale precision, which is extremely challenging to achieve for current materials and nanostructuring technologies. Imperfections inherently lead to spectral mismatch of the extraction (leaky) modes with color center emission lines. Here, we demonstrate a new and simple two‐step method for fabricating diamond PhC slabs with leaky modes overlapping the emission line of the silicon vacancy (SiV) centers. In the first step, the PhC structure with leaky modes blue shifted from the SiV emission line is fabricated in a nanocrystalline diamond without SiV centers. A thin layer of SiV‐rich diamond is then deposited over the PhC slab so that the spectral position of the PhC leaky modes is adjusted to the emission line of the SiV centers, thereby avoiding the need for nanoscale precision of the structuring method. An intensity enhancement of the zero‐phonon line of the SiV centers by a factor of nine is achieved. The color centers in the thin surface layer are beneficial for sensing applications and their properties can also be further controlled by the diamond surface chemistry. The demonstrated PhC tuning method can also be easily adapted to other optical centers and photonic structures of different types in diamond and other materials. Materials science ; Diamond ; Optoelectronics ; Photonic crystal ; Photonics ; Silicon ; Optics ; Nanotechnology Diamond and Carbon-based Materials Research ; Photonic Crystals and Applications ; Advanced Fiber Laser Technologies
Authors: Bhavani Prasad Yalagala | Sweety Deswal | Siva Rama Krishna Vanjari | Ravinder Dahiya
Source: 2021 IEEE International Conference on Flexible and Printable Sensors and Systems (FLEPS) (article, 2021-06-20)
Field: Materials Science — Biomaterials

Flexible and ultra-fast bioresorbable nanofibers of silk fibroin-PVA composite Electronic devices capable of easily degradable, physically destructible, and bioresorbable which are prepared using abundant and natural biomaterials has been an interesting research topic. These transient electronic devices help in the reduction of non-degradable electronic waste and can be explored for the next generation intelligent security applications. Here, in the current work a fully transient novel SF-PVA composite based flexible and biocompatible nanofibers were successfully prepared via simple and facile electrospinning based approach. Combining the silk fibroin with PVA has induced different structural transitions i.e. percentage change in the secondary structures which are studied using XRD and FTIR analysis. Besides, the chemical and morphological studies were done using the Raman, and FESEM analysis. The dissolution tests were performed on ultra-thin electrospun nanofibrous mats which revealed the ultra-fast dissolution of nanofibers in both DI water as well as in PBS with a dissolution time of less than 3 seconds. The as prepared nanofibers exhibit programmable dissolutions, superior mechanical flexibility for the different concentration ratio of PVA without further affecting its morphological properties. The tunable degradation rates are primarily due to the change in the structural transitions induced due to the variation in the percentage of the beta sheets which are conformed from the XRD and FTIR-FSD analysis. Thus, the novel nanocomposite biomaterial based nanofibers paves the path towards the development of the upcoming flexible and transient electronic applications. Fibroin ; Nanofiber ; Electrospinning ; Materials science ; SILK ; Nanocomposite ; Dissolution ; Fourier transform infrared spectroscopy ; Composite number ; Nanotechnology ; Raman spectroscopy ; Chemical engineering ; Composite material ; Polymer Electrospun Nanofibers in Biomedical Applications ; Silk-based biomaterials and applications ; Advanced Sensor and Energy Harvesting Materials
Authors: Akihiro Yonezawa | Naoki Tanaka | Hayase Yoshiki | Makoto Sano | Toshimitsu Suzuki | Takanori Miyake
Source: Journal of the Japan Petroleum Institute (article, 2021-04-30)
Field: Chemistry — Inorganic Chemistry

Molecular-sieving Separation of &lt;i&gt;p&lt;/i&gt;-Xylene with Metal-organic Frameworks Metal-organic frameworks (MOFs) consisting of organic linker such as terephthalic acid or fumaric acid and cation such as Al3+ or Zr4+ were prepared by the hydro- and solvo-thermal methods. MOFs were characterized by XRD, N2 adsorption-desorption isotherm and FE-SEM. The prepared MOFs were mostly crystalline and phase-pure. MOFs were used as the column packing for chromatographic separation of p-xylene from a xylene mixture. With MOFs prepared with large linker molecules, xylenes diffused into the micropores and eluted fundamentally according to kinetic molecular size. With MOFs of low crystallinity or very small micropores, xylenes passed through spaces between MOF particles and separation of p-xylene was not possible. With MOFs consisting of fumaric acid and Zr4+ (MOF-801), o- and m-xylenes eluted quickly and p-xylene eluted later, because o- and m-xylenes passed through spaces between MOF particles, whereas p-xylene diffused into the micropores of MOF-801. Temperature dependence of separation with MOF-801 revealed that at temperatures lower than 140 °C, xylenes could not diffuse into the micropores. At 170 °C, the smallest p-xylene diffused into the micropores and thus p-xylene could be separated from o- and m-xylenes by the molecular-sieving mechanism. MOF-801 was robust against repeated exposure to xylenes and heat treatment at high temperature for elution of adsorbed xylene. Terephthalic acid ; Chemistry ; Adsorption ; p-Xylene ; Crystallinity ; Fumaric acid ; Metal-organic framework ; Xylene ; Microporous material ; Elution ; o-Xylene ; Desorption ; Chemical engineering ; Inorganic chemistry ; Organic chemistry ; Chromatography ; Catalysis ; Toluene ; Crystallography ; Polyester Metal-Organic Frameworks: Synthesis and Applications ; X-ray Diffraction in Crystallography ; Dendrimers and Hyperbranched Polymers
Authors: Zsombor Miskolczy | Mónika Megyesi | Stephan Sinn | Frank Biedermann | László Biczók
Source: Chemical Communications (article, 2021-01-01)
Field: Chemistry — Spectroscopy

Simultaneous analyte indicator binding assay (SBA) for the monitoring of reversible host–guest complexation kinetics Very little information is available on the kinetics of the self-assembly and dissociation of optically silent building blocks despite the importance of such data in the rational design of tailor-made host-guest systems. We introduce here a novel time-resolved method that enables the simultaneous determination of complex formation and complex dissociation rate constants for inclusion-type host-guest complexes. The simultaneous analyte indicator binding assay (SBA) gives also direct access to binding affinities, thus largely simplifying the experimental procedure for a full kinetic and thermodynamic characterisation of host-guest systems. Analyte ; Kinetics ; Chemistry ; Receptor–ligand kinetics ; Competitive binding ; Host (biology) ; Kinetic energy ; Combinatorial chemistry ; Chromatography ; Biochemistry Molecular Sensors and Ion Detection ; Supramolecular Chemistry and Complexes ; Protein Interaction Studies and Fluorescence Analysis
Authors: Indrajit Maity | Charu Sharma | Francisco Lossada | Andreas Walther
Source: Angewandte Chemie (article, 2021-08-04)
Field: Materials Science — Biomaterials

Feedback and Communication in Active Hydrogel Spheres with pH Fronts: Facile Approaches to Grow Soft Hydrogel Structures Abstract Compartmentalized reaction networks regulating signal processing, communication and pattern formation are central to living systems. Towards achieving life‐like materials, we compartmentalized urea‐urease and more complex urea‐urease/ester‐esterase pH‐feedback reaction networks into hydrogel spheres and investigate how fuel‐driven pH fronts can be sent out from these spheres and regulated by internal reaction networks. Membrane characteristics are installed by covering urease spheres with responsive hydrogel shells. We then encapsulate the two networks (urea‐urease and ester‐esterase) separately into different hydrogel spheres to devise communication, pattern formation and attraction. Moreover, these pH fronts and patterns can be used for self‐growing hydrogels, and for developing complex geometries from non‐injectable hydrogels without 3D printing tools. This study opens possibilities for compartmentalized feedback reactions and their use in next generation materials fabrication. Urease ; Self-healing hydrogels ; Urea ; SPHERES ; Esterase ; Chemistry ; Membrane ; Nanotechnology ; Chemical engineering ; Materials science ; Polymer chemistry ; Organic chemistry ; Enzyme ; Biochemistry ; Physics Supramolecular Self-Assembly in Materials ; Photoreceptor and optogenetics research ; Advanced biosensing and bioanalysis techniques
Authors: Annalena Gärtner | Matthäus Marek | Merle Arrowsmith | Dominic Auerhammer | Krzysztof Radacki | Dominic Prieschl | Rian D. Dewhurst | Holger Braunschweig
Source: Chemistry - A European Journal (article, 2021-04-08)
Field: Chemistry — Organic Chemistry

Boron‐ versus Nitrogen‐Centered Nucleophilic Reactivity of (Cyano)hydroboryl Anions: Synthesis of Cyano(hydro)organoboranes and 2‐Aza‐1,4‐diborabutatrienes Cyclic alkyl(amino)carbene-stabilized (cyano)hydroboryl anions were synthesized by deprotonation of (cyano)dihydroborane precursors. While they display boron-centered nucleophilic reactivity towards organohalides, generating fully unsymmetrically substituted cyano(hydro)organoboranes, they show cyano-nitrogen-centered nucleophilic reactivity towards haloboranes, resulting in the formation of hitherto unknown linear 2-aza-1,4-diborabutatrienes. Reactivity (psychology) ; Chemistry ; Nucleophile ; Deprotonation ; Carbene ; Medicinal chemistry ; Boron ; Alkyl ; Nucleophilic addition ; Nitrogen ; Organic chemistry ; Ion ; Catalysis Organoboron and organosilicon chemistry ; N-Heterocyclic Carbenes in Organic and Inorganic Chemistry ; Catalytic Cross-Coupling Reactions
Authors: Xu Zhang | Xiang Zhang | Pulickel M. Ajayan | Jianguo Wen | Horacio D. Espinosa
Source: Small (article, 2021-11-16)
Field: Materials Science — Materials Chemistry

Edge‐Mediated Annihilation of Vacancy Clusters in Monolayer Molybdenum Diselenide (MoSe<sub>2</sub>) under Electron Beam Irradiation Annihilation of vacancy clusters in monolayer molybdenum diselenide (MoSe<sub>2</sub> ) under electron beam irradiation is reported. In situ high-resolution transmission electron microscopy observation reveals that the annihilation is achieved by diffusion of vacancies to the free edge near the vacancy clusters. Monte Carlo simulations confirm that it is energetically favorable for the vacancies to locate at the free edge. By computing the minimum energy path for the annihilation of one vacancy cluster as a case study, it is further shown that electron beam irradiation and pre-stress in the suspended MoSe<sub>2</sub> monolayer are necessary for the vacancies to overcome the energy barriers for diffusion. The findings suggest a new mechanism of vacancy healing in 2D materials and broaden the capability of electron beam for defect engineering of 2D materials, a promising way of tuning their properties for engineering applications. Vacancy defect ; Materials science ; Monolayer ; Electron beam processing ; Annihilation ; Irradiation ; Molecular physics ; Cluster (spacecraft) ; Chemical physics ; Atomic physics ; Condensed matter physics ; Nanotechnology ; Chemistry ; Physics ; Nuclear physics 2D Materials and Applications ; MXene and MAX Phase Materials ; Quantum Dots Synthesis And Properties
Authors: Mateja Đud | Markéta Tichotová | Eliška Procházková | Ondřej Baszczyňski
Source: Molecules (article, 2021-08-25)
Field: Materials Science — Biomaterials

Phosphate-Based Self-Immolative Linkers for the Delivery of Amine-Containing Drugs Amine-containing drugs often show poor pharmacological properties, but these disadvantages can be overcome by using a prodrug approach involving self-immolative linkers. Accordingly, we designed l-lactate linkers as ideal candidates for amine delivery. Furthermore, we designed linkers bearing two different cargos (aniline and phenol) for preferential amine cargo release within 15 min. Since the linkers carrying secondary amine cargo showed high stability at physiological pH, we used our strategy to prepare phosphate-based prodrugs of the antibiotic Ciprofloxacin. Therefore, our study will facilitate the rational design of new and more effective drug delivery systems for amine-containing drugs. Amine gas treating ; Prodrug ; Chemistry ; Combinatorial chemistry ; Drug delivery ; Aniline ; Phosphate ; Organic chemistry ; Biochemistry Supramolecular Self-Assembly in Materials ; RNA Interference and Gene Delivery ; Photochromic and Fluorescence Chemistry