jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Andrey N. Pravdivtsev | Kai Buckenmaier | Nicolas Kempf | Gabrielle Stevanato | Klaus Scheffler | J Engelmann | Markus Plaumann | Rainer Koerber | Jan‐Bernd Hövener | Thomas Theis
Source: arXiv (Cornell University) (preprint, 2023-02-18)
Field: Chemistry — Spectroscopy

LIGHT-SABRE hyperpolarizes 1-^{13}C-pyruvate continuously, without magnetic field cycling Nuclear spin hyperpolarization enables real-time observation of metabolism and intermolecular interactions in vivo. 1-13C-Pyruvate is the leading hyperpolarized tracer currently under evaluation in several clinical trials as a promising molecular imaging agent. Still, the quest for a simple, fast, and efficient hyperpolarization technique is ongoing. Here, we describe that continuous, weak irradiation in the audio-frequency range of the 13C spin at 121 μT magnetic field (\sim twiceEarth\apos s field) enables spin order transfer from parahydrogen to 13C magnetization of 1-13C-pyruvate. These so-called LIGHT-SABRE pulses couple nuclear spin states of parahydrogen and pyruvate via the J-coupling network of reversibly exchanging Ir-complexes. Using \sim 100% parahydrogen at ambient pressure, we polarized 51 mM of 1-13C-pyruvate in the presence of 5.1 mM Ir-complex continuously and repeatedly to a polarization of 1.1% averaged over free and catalyst-bound pyruvate. The experiments were conducted at -8°C), where almost exclusively bound pyruvate was observed, corresponding to an estimated 11% polarization on bound pyruvate. The obtained hyperpolarization levels closely match those obtained via SABRE-SHEATH under otherwise identical conditions. The creation of three different types of spin orders was observed: transverse 13C magnetization along the applied magnetic field, 13C z-magnetization along the main field B_0, and 13C-1H zz-spin-order. With a superconducting quantum interference device (SQUID) for detection, we found that the generated spin orders result from tiny 1H-13C J-coupling interactions, which are not visible even with our narrow linewidth below 0.3 Hz. Hyperpolarization (physics) ; Spin isomers of hydrogen ; Magnetization ; Magnetization transfer ; Polarization (electrochemistry) ; Physics ; Magnetic field ; Nuclear magnetic resonance ; Condensed matter physics ; Chemistry ; Nuclear magnetic resonance spectroscopy ; Hydrogen ; Physical chemistry Advanced NMR Techniques and Applications ; Electron Spin Resonance Studies ; Advanced MRI Techniques and Applications
Authors: Jun Qian | Chunjie Chen | Liang Ma | Yida Wang
Source: Zeitschrift für Kristallographie - New Crystal Structures (article, 2023-10-31)
Field: Chemistry — Inorganic Chemistry

Crystal structure of (2-(2-pyridine)-benzimidazole-<i>κ</i> <sup>2</sup> N,N′)-bis(1-phenylpyrazole-<i>κ</i> <sup>2</sup> C,N)iridium(III) hexafluorophosphate, C<sub>30</sub>H<sub>22</sub>F<sub>6</sub>IrN<sub>7</sub>P Abstract C 30 H 22 F 6 IrN 7 P, monoclinic, P 2 1 / c (no. 4), a = 8.8876(3) Å, b = 32.8428(9) Å, c = 10.5010(3) Å, β = 106.623(2) ∘ , V = 2937.07(16) Å 3 , Z = 4, R gt ( F ) = 0.0572, wR ref ( F 2 ) = 0.1171, T = 293 K. Hexafluorophosphate ; Monoclinic crystal system ; Benzimidazole ; Iridium ; Crystal structure ; Pyridine ; Crystallography ; Crystal (programming language) ; Physics ; Chemistry ; Stereochemistry ; Medicinal chemistry ; Ionic liquid Metal-Organic Frameworks: Synthesis and Applications ; Luminescence and Fluorescent Materials ; Synthesis and Characterization of Heterocyclic Compounds
Authors: Carla Calvó‐Tusell | Zhen Liu | Kai Chen | Frances H. Arnold | Marc Garcia‐Borràs
Source: Angewandte Chemie (article, 2023-06-01)
Field: Chemistry — Organic Chemistry

Reversing the Enantioselectivity of Enzymatic Carbene N−H Insertion Through Mechanism‐Guided Protein Engineering** Abstract We report a computationally driven approach to access enantiodivergent enzymatic carbene N−H insertions catalyzed by P411 enzymes. Computational modeling was employed to rationally guide engineering efforts to control the accessible conformations of a key lactone‐carbene (LAC) intermediate in the enzyme active site by installing a new H‐bond anchoring point. This H‐bonding interaction controls the relative orientation of the reactive carbene intermediate, orienting it for an enantioselective N ‐nucleophilic attack by the amine substrate. By combining MD simulations and site‐saturation mutagenesis and screening targeted to only two key residues, we were able to reverse the stereoselectivity of previously engineered S ‐selective P411 enzymes. The resulting variant, L5_FL‐B3 , accepts a broad scope of amine substrates for N−H insertion with excellent yields (up to &gt;99 %), high efficiency (up to 12 300 TTN), and good enantiocontrol (up to 7 : 93 er ). Carbene ; Chemistry ; Combinatorial chemistry ; Stereochemistry ; Protein engineering ; Amine gas treating ; Active site ; Nucleophile ; Enantioselective synthesis ; Enzyme kinetics ; Substrate (aquarium) ; Directed evolution ; Saturated mutagenesis ; Enzyme ; Catalysis ; Organic chemistry ; Biochemistry ; Biology Cyclopropane Reaction Mechanisms ; Enzyme Catalysis and Immobilization ; Biochemical and Molecular Research
Authors: Nils Christian Keppler | Adrian Hannebauer | Karen D. J. Hindricks | Saskia Zailskas | Andreas Schaate | Peter Behrens
Source: Chemistry - An Asian Journal (article, 2023-09-15)
Field: Chemistry — Inorganic Chemistry

Transmission Porosimetry Study on High‐quality Zr‐fum‐MOF Thin Films Crystalline Zr-fum-MOF (MOF-801) thin films of high quality are prepared on glass and silicon substrates by direct growth under solvothermal conditions. The synthesis is described in detail and the influence of different synthesis parameters such as temperature, precursor concentration, and the substrate type on the quality of the coatings is illustrated. Zr-fum-MOF thin films are characterized in terms of crystallinity, porosity, and homogeneity. Dense films of optical quality are obtained. The sorption behavior of the thin films is studied with various adsorptives. It can be easily monitored by measuring the transmission of the films in gas flows of different compositions. This simple transmission measurement at only one wavelength allows a very fast evaluation of the adsorption properties of thin films as compared to traditional sorption methods. The sorption behavior of the thin films is compared with the sorption properties of Zr-fum-MOF powder samples. Sorption ; Materials science ; Crystallinity ; Thin film ; Porosimetry ; Chemical engineering ; Porosity ; Homogeneity (statistics) ; Substrate (aquarium) ; Adsorption ; Composite material ; Nanotechnology ; Porous medium ; Organic chemistry ; Chemistry ; Computer science Metal-Organic Frameworks: Synthesis and Applications ; Gas Sensing Nanomaterials and Sensors ; ZnO doping and properties
Authors: Bondili Sesharamsingh | Jaya Kumar | I. V. Kasi Viswanath | G.S.N. Koteswara Rao | Venkateswara Rao Anna
Source: Future Journal of Pharmaceutical Sciences (article, 2023-11-10)
Field: Chemistry — Analytical Chemistry

Development of stability-indicating HPLC method for quantification of pharmacopeia impurities of Zuclopenthixol and characterization of its stress degradation products by LCMS/MS Abstract Background The present study focused to develop a simple and sensitive HPLC method for resolution and estimation process-related impurities of zuclopenthixol and further assessment of forced degradation behavior of zuclopenthixol. Results The chromatographic separation of drug substance, process-related impurities and its degradation products (DPs) was achieved on KNAUER C18 (250 mm × 4.6 mm, 5µ id) column at that was maintained at 35 °C temperature using 0.1 M sodium acetate buffer at pH 4.3 and methanol in 20:80 (v/v) as mobile phase A, 0.1% formic acid and acetonitrile in 75:25 (v/v) as mobile phase B. Equal volume of mobile phase A and B was pumped in isocratic elution at 0.8 mL/min. Detection wavelength was selected as 257 nm. In the proposed conditions, zuclopenthixol is identified at 6.91 and 1.91 min and 2.89 min, respectively, for impurity B and A min with acceptable system suitability and specificity. The method produces LOD at 0.009 for impurities with calibration range of 30–180 µg/mL for zuclopenthixol and 0.03–0.18 µg/mL for impurities. The other validation parameters were notices to be with in the acceptable levels for zuclopenthixol and its impurities. The drug was exposed to different stressed conditions (acid, base, peroxide, thermal and UV light) according to ICH Q1A (R2) guidelines. The DPs formed during the stress study were identified and characterized by LCMS/MS in ESI positive mode. Conclusion The analysis involved a comparison of collision-induced dissociation mass spectrometry data between the degradation products and zuclopenthixol. As a result, potential structures for six degradation compounds were suggested. The results from additional validation studies were similarly pleasing and demonstrated their suitability for the routine analysis of zuclopenthixol and its associated impurities in both bulk drug and pharmaceutical dosage forms. Additionally, these findings can be extended to assess the mechanism of stress degradation in zuclopenthixol. Forced degradation ; Impurity ; Chemistry ; Chromatography ; Formic acid ; Methanol ; High-performance liquid chromatography ; Acetonitrile ; Degradation (telecommunications) ; Acetic acid ; Reversed-phase chromatography ; Biochemistry Analytical Methods in Pharmaceuticals ; Analytical Chemistry and Chromatography ; Antibiotics Pharmacokinetics and Efficacy
Authors: Deepti Raj | Gabriele Barrera | Federico Scaglione | Federica Celegato | Matteo Cialone | Marco Coïsson | Paola Tiberto | Jordi Sort | Paola Rizzi | Eva Pellicer
Source: Nanomaterials (article, 2023-01-19)
Field: Materials Science — Materials Chemistry

Electrochemical Synthesis, Magnetic and Optical Characterisation of FePd Dense and Mesoporous Nanowires Dense and mesoporous FePd nanowires (NWs) with 45 to 60 at.% Pd content were successfully fabricated by template- and micelle-assisted pulsed potentiostatic electrodeposition using nanoporous anodic alumina and polycarbonate templates of varying pore sizes. An FePd electrolyte was utilized for obtaining dense NWs while a block copolymer, P-123, was added to this electrolyte as the micelle-forming surfactant to produce mesoporous NWs. The structural and magnetic properties of the NWs were investigated by electron microscopy, X-ray diffraction, and vibrating sample magnetometry. The as-prepared NWs were single phase with a face-centered cubic structure exhibiting 3.1 µm to 7.1 µm of length. Mesoporous NWs revealed a core-shell structure where the porosity was only witnessed in the internal volume of the NW while the outer surface remained non-porous. Magnetic measurements revealed that the samples displayed a soft ferromagnetic behavior that depended on the shape anisotropy and the interwire dipolar interactions. The mesoporous core and dense shell structure of the NWs were seen to be slightly affecting the magnetic properties. Moreover, mesoporous NWs performed excellently as SERS substrates for the detection of 4,4'-bipyridine, showing a low detection limit of 10<sup>-12</sup> M. The signal enhancement can be attributed to the mesoporous morphology as well as the close proximity of the embedded NWs being conducive to localized surface plasmon resonance. Materials science ; Mesoporous material ; Nanowire ; Nanotechnology ; Chemical engineering ; Superparamagnetism ; Nanoporous ; Micelle ; Electrolyte ; Electrode ; Magnetization ; Chemistry Anodic Oxide Films and Nanostructures ; Nanoporous metals and alloys ; Electrocatalysts for Energy Conversion
Authors: Shantanu Saha | Shrivatch Sankar | Sk Shafaat Saud Nikor | Shamsul Arafin
Source: physica status solidi (RRL) - Rapid Research Letters (review, 2023-06-10)
Field: Materials Science — Materials Chemistry

A Review of Intercalation of Rare Gas Solids on Graphene and Hexagonal Boron Nitride Intercalation has recently emerged as a powerful tool due to its unique capability of modifying the properties of materials without breaking their chemical bonds. The ultrathin lattice structure of two‐dimensional (2D) materials with strong in‐plane covalent bonding and weak out‐of‐plane bonding between neighboring layers allow for the successful utilization of this powerful technique. The physics and chemistry of intercalated foreign species in 2D host materials, especially graphene and hexagonal boron nitride (h‐BN), are the focus of this review article. Among many foreign species, special attention is given to rare gas solids that introduce unprecedented physical and chemical properties in the targeted host materials. The historical background of intercalation is briefly discussed, and a comprehensive review of the very recent progress in the intercalation of rare gas solids in graphene and h‐BN is then provided. Different technologies used for the growth of the host materials and for the intercalation of rare gas species are also described. The remarkable potential of the resulting hybrid materials is outlined for diverse applications, including sensing, water filtration, and nanoelectromechanical devices. Intercalation (chemistry) ; Graphene ; Hexagonal boron nitride ; Nanotechnology ; Materials science ; Boron nitride ; Covalent bond ; Chemical bond ; Chemical physics ; Chemistry ; Inorganic chemistry ; Organic chemistry Graphene research and applications ; 2D Materials and Applications ; MXene and MAX Phase Materials
Authors: Domenic Pace | Reece Crocker | William J. Kendrick | Bolong Zhang | Wallace W. H. Wong | Mohan Bhadbhade | Timothy W. Schmidt | Thành Vinh Nguyễn
Source: ChemRxiv (preprint, 2023-02-27)
Field: Materials Science — Materials Chemistry

Tuning Solid-State Emission with Molecular Torsion in Dibenzosuberenylidene-Derived Organic Dyes The solid-state emission of organic compounds is required for many opto-electronic applications. However, it remains challenging to modify the emission properties of existing solid-state emissive organic frameworks, due to their inherently complicated structure-activity relationships. Herein, we report the design and construction of a new family of solid-state luminogens based on the dibenzosuberenylidene scaffold. The dyes exhibit interesting crystallization-induced emission enhancement (CIEE) behavior, which can be fine-tuned via easily implemented structural modifications to result in a range of fluorescence colors and intensities. Solid-state ; Fluorescence ; Materials science ; Crystallization ; Aggregation-induced emission ; Nanotechnology ; Chemical physics ; Optoelectronics ; Chemistry ; Physical chemistry ; Organic chemistry ; Optics ; Physics Luminescence and Fluorescent Materials ; Nanoplatforms for cancer theranostics ; Molecular Sensors and Ion Detection
Authors: Florian D’Ambra | V. Faucheux | Emmanuel Nicolas | Thibault Cantat | Gérard Gebel | Parviz Hajiyev
Source: ChemRxiv (preprint, 2023-10-11)
Field: Chemistry — Organic Chemistry

Direct enthalpy measurement for hydrogenation of liquid organic hydrogen carriers by Differential Scanning Calorimetry under H2 pressure In this contribution, we report the hydrogenation enthalpy direct measurement of well-studied Liquid Organic Hydrogen Carriers (LOHC) (Dibenzyltoluene, N-Ethylcarbazole, 2-Octanone) and of a new LOHC (Acetophenone) by differential scanning calorimetry (DSC) under H2 pressure. The obtained hydrogenation enthalpies showed good correspondence with DFT predictions and the literature. Moreover, multistep hydrogenation processes were investigated, evidencing that transfer hydrogenation occurred during the reaction. The study of bifunctional LOHC such as acetophenone and its derivatives showcased the potential of direct enthalpy measurement for rapid LOHC screening. Besides, a DFT correction factor for this specific bifunctional LOHC class was experimentally obtained, enabling more precise DFT predictions for similar systems. Kinetic parameters such as the activation energies for the catalytic Ru/Al2O3 system were also determined to be in the 45-60 kJ/mol range, compatible with the H2 adsorption on the Ru surface. The detrimental effect of steric hinderance was also observed. Finally, the reaction order in H2 was experimentally estimated to ~1 for all of the studied LOHCs. Bifunctional ; Acetophenone ; Enthalpy ; Differential scanning calorimetry ; Chemistry ; Steric effects ; Catalysis ; Hydrogen ; Physical chemistry ; Organic chemistry ; Thermodynamics Chemical Thermodynamics and Molecular Structure ; Thermal and Kinetic Analysis ; Thermodynamic properties of mixtures
Authors: Andrijana Šolajić | Jelena Pešić
Source: Research Square (preprint, 2023-10-31)
Field: Materials Science — Materials Chemistry

Tailoring Electronic and Optical Properties of hBN/InTe and hBN/GaTe Heterostructures Through Biaxial Strain Engineering Abstract In this research study, we systematically investigate the electronic and optical properties of van der Waals heterostructures (HSs) consisting of InTe (GaTe) and hBN monolayers, subjected to controlled biaxial strain. Our analysis demonstrates that the application of strain induces noteworthy alterations in the electronic band structure, enabling precise manipulation of the band gap and augmentation of the absorption properties of these structures. Employing density functional theory, we conduct a comprehensive examination of the influence of strain on the electronic and optical characteristics of these HSs. Our investigation showcases the remarkable potential of strain engineering in rendering these heterostructures into efficient and robust wide-range absorbers, particularly optimised for the visible spectrum, underscoring their relevance in various photonic and optoelectronic applications, paving the way for integration into advanced nanodevices. Strain engineering ; Heterojunction ; Materials science ; Optoelectronics ; Strain (injury) ; van der Waals force ; Density functional theory ; Photonics ; Monolayer ; Nanotechnology ; Physics 2D Materials and Applications ; Boron and Carbon Nanomaterials Research ; MXene and MAX Phase Materials
Authors: Selma Mestour | Sarra Melloul | Abdeslam-Hassen Méniai
Source: Preprints.org (preprint, 2023-07-20)
Field: Chemistry — Organic Chemistry

Supercritical Fluid Extraction of Algerian Onion Seed Oils and Optimization of the Composition Onion is not just an edible food but its seeds can also be an important source of valuable oil with various sensitive applications mainly in pharmaceutical, cosmetic and food fields. This has encouraged the use of a supercritical fluid extraction in the present study to obtain oil from local onion seeds, hence avoiding even traces of organic solvents. For several advantages carbon dioxide at supercritical conditions was used as the fluid. The effects of four key operating parameters like pressure, temperature, particle size and CO2 mass flowrate were investigated in ranges of [150, 250 bars], [35, 65°C], [0.25, 0.85mm] and [50, 100g/min], respectively, using a Box-Behnken experimental design, for a constant extraction time of 3 hours. This led to optimal operating conditions of 250 bar, 57°C, 0.25mm and 50g CO2/min for the highest oil extraction yield value of 24.36%. Furthermore, gas chromatography-mass spectrometry (GC-MS) was used to identify qualitatively and quantitatively the chemical composition of the onion seed oils. About ten components were identified in the extracts, but with four major ones, namely 9,12-Octadecadienoic acid ,methyl ester, 9,12-Octadecadienoic acid (Z,Z)-,methyl ester, 9-Octadecadienoic acid (Z)-,methyl ester and Hexadecanoic acid, methyl ester, present with significant percentages, depending on the operating parameters values. These fatty acids are well known for their benefits for human health. Finally the study shows the importance and the merits of fluids when used under particular conditions of pressure and temperature, in very sensitive industrial fields. Extraction (chemistry) ; Supercritical fluid ; Supercritical carbon dioxide ; Supercritical fluid extraction ; Chemistry ; Chromatography ; Yield (engineering) ; Response surface methodology ; Gas chromatography–mass spectrometry ; Carbon dioxide ; Mass spectrometry ; Materials science ; Organic chemistry Edible Oils Quality and Analysis ; Essential Oils and Antimicrobial Activity
Authors: Frederik Peschke | Andrea Taladriz‐Sender | Matthew J. Andrews | Allan J. B. Watson | Glenn A. Burley
Source: Angewandte Chemie (article, 2023-10-31)
Field: Chemistry — Organic Chemistry

Glutathione Mediates Control of Dual Differential Bio‐orthogonal Labelling of Biomolecules Traditional approaches to bio-orthogonal reaction discovery have focused on developing reagent pairs that react with each other faster than they are metabolically degraded. Glutathione (GSH) is typically responsible for the deactivation of most bio-orthogonal reagents. Here we demonstrate that GSH promotes a Cu-catalysed (3+2) cycloaddition reaction between an ynamine and an azide. We show that GSH acts as a redox modulator to control the Cu oxidation state in these cycloadditions. Rate enhancement of this reaction is specific for ynamine substrates and is tuneable by the Cu:GSH ratio. This unique GSH-mediated reactivity gradient is then utilised in the dual sequential bio-orthogonal labelling of peptides and oligonucleotides via two distinct chemoselective (3+2) cycloadditions. Cycloaddition ; Glutathione ; Chemistry ; Reagent ; Reactivity (psychology) ; Combinatorial chemistry ; Biomolecule ; Redox ; Labelling ; Reactive intermediate ; Bioorthogonal chemistry ; Click chemistry ; Organic chemistry ; Biochemistry ; Enzyme Click Chemistry and Applications ; Chemical Synthesis and Analysis ; Biotin and Related Studies
Authors: P. V. Nikul’shin | Roman G. Fedunov | L. V. Kuibida | А. M. Maksimov | Evgeni M. Glebov | Dmitri V. Stass
Source: International Journal of Molecular Sciences (article, 2023-04-20)
Field: Chemistry — Organic Chemistry

Recombination of X-ray-Generated Radical Ion Pairs in Alkane Solution Assembles Optically Inaccessible Exciplexes from a Series of Perfluorinated para-Oligophenylenes with N,N-Dimethylaniline We demonstrate that a series of perfluorinated <i>para</i>-oligophenylenes C<sub>6</sub>F<sub>5</sub>-(C<sub>6</sub>F<sub>4</sub>)<sub>n</sub>-C<sub>6</sub>F<sub>5</sub> (<i>n</i> = 1-3) produce exciplexes with <i>N</i>,<i>N</i>-dimethylaniline (DMA) in degassed X-irradiated <i>n</i>-dodecane solutions. The optical characterization of the compounds shows that their short fluorescence lifetimes (ca. 1.2 ns) and UV-Vis absorption spectra, overlapping with the spectrum of DMA with molar absorption coefficients of 2.7-4.6 × 10<sup>4</sup> M<sup>-1</sup>cm<sup>-1</sup>, preclude the standard photochemical exciplex formation pathway via selective optical generation of the local excited state of the donor and its bulk quenching by the acceptor. However, under X-rays, the efficient assembly of such exciplexes proceeds via the recombination of radical ion pairs, which delivers the two partners close to each other and ensures a sufficient energy deposition. The exciplex emission is completely quenched by the equilibration of the solution with air, providing a lower bound of exciplex emission lifetime of ca. 200 ns. The recombination nature of the exciplexes is confirmed by the magnetic field sensitivity of the exciplex emission band inherited from the magnetic field sensitivity from the recombination of spin-correlated radical ion pairs. Exciplex formation in such systems is further supported by DFT calculations. These first exciplexes from fully fluorinated compounds show the largest known red shift of the exciplex emission from the local emission band, suggesting the potential of perfluoro compounds for optimizing optical emitters. Alkane ; Dimethylaniline ; Photochemistry ; Chemistry ; Ion ; X-ray ; Radical ion ; Organic chemistry ; Hydrocarbon ; Physics ; Optics Radical Photochemical Reactions ; Fluorine in Organic Chemistry ; Luminescence and Fluorescent Materials