jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Fatimah Ali Hussein | Meenakshi Joshi | Sandeep Kaur‐Ghumaan | Matthias Stein
Source: ChemCatChem (article, 2024-05-29)
Field: Chemistry — Inorganic Chemistry

Hydrogen Evolving Mono‐Nuclear Manganese Complexes with Carefully Positioned Pyridine Base Ligands Abstract Enormous efforts have been made by the scientific community in the development of bio‐mimetic/bio‐inspired hydrogen‐evolving complexes as catalysts for an alternative hydrogen energy carrier and renewable energy sources. In this regard, new bio‐inspired mono‐nuclear Mn(I) carbonyl model complexes fac ‐[(Mn(CO) 3 (κ 2 ‐SN 2 C 7 H 5 )(κ 1 ‐PPh 2 Py))] 1 and fac ‐[(Mn(CO) 3 (κ 2 ‐S 2 NC 7 H 4 )(κ 1 ‐PPh 2 Py))] 2 with 2‐mercaptobenzimidazole (N,N) and 2‐mercaptobenzothiazole (S,N) ligands and a N‐based phosphine ligand (PPh 2 Py) have been synthesized, spectroscopically characterized and evaluated as electro‐catalysts for hydrogen generation. In contrast to related mono‐nuclear (N,N/S,N)−Mn−PPh 3 complexes, the newly introduced pyridine nitrogen atom of the PPh 2 Py ligand placed in an axial position in the second coordination sphere of the Mn(I) complexes, provides a first site for protonation and enables a fast intra‐molecular proton transfer to the central metal atom with a weaker acid. Theoretical DFT calculations enable a detailed picture of catalytic pathways, assign redox transitions and structural changes. Both the molecular complexes were tested as electro‐catalysts for hydrogen generation in CH 3 CN. Complexes 1 and 2 effectively catalyzed the electrochemical proton reduction with the weaker acetic acid as the proton source and displayed a turnover frequency ( TOF /s −1 ; overpotential, η/V) of 610; 1.02 and 615; 1.12, respectively. [Correction added on 25 July 2024, after first online publication: Preceding sentence was updated.] The computer‐aided design of dedicated proton transfer pathways from second coordination sphere ligands is thus able to allow a hydrogen evolution reactivity with a weaker acid (acetic acid). Manganese ; Pyridine ; Chemistry ; Base (topology) ; Hydrogen ; Inorganic chemistry ; Combinatorial chemistry ; Organic chemistry Asymmetric Hydrogenation and Catalysis ; Magnetism in coordination complexes ; Metalloenzymes and iron-sulfur proteins
Authors: Oscar Gayraud | Frédéric Guégan
Source: ChemRxiv (preprint, 2024-02-08)
Field: Chemistry — Spectroscopy

Automated exploration of the conformational degrees of freedom along reaction profiles - driving a FASTCAR This publication aims at presenting a Python-based workflow designed to enable a fully automatised and exhaustive exploration of the conformational degrees of freedom within the calculation of reaction paths in molecular systems. The proposed strategy focuses on effectively representing the lowest energy conformers for intricate, highly rotatable, and non-intuitive transition states, reagents and products, using existing computational tools. The article presents a workflow that is demonstrated through the application of two chemical reactions: a Diels-Alder reaction involving 4,4-dimethyl-3-methylenepent-1-ene and (E)-dec-5-ene, and an intramolecular acid-catalysed cyclization reaction of polycyclic azocane derivative, which both prove to be challenging to study "by hand". The proposed methodology is expected to be of a great help in the modelling of state-of-the art organic chemistry reactions, whose complexity is ever increasing. Degrees of freedom (physics and chemistry) ; Chemistry ; Physics ; Thermodynamics Analytical Chemistry and Chromatography ; Molecular spectroscopy and chirality ; Various Chemistry Research Topics
Authors: David Brown | Méryll Barraco | Nieck E. Benes | Sylvie Neyertz
Source: The Journal of Physical Chemistry A (article, 2024-08-13)
Field: Chemistry — Physical and Theoretical Chemistry

Development of All-Atom Empirical Potentials for Phloroglucinol (Phg) and Hexachlorocyclotriphosphazene (HCCP) Based on their Crystal Phase Structures Two existing generic force fields have been augmented with partial charges and tuned in order to give intercompatible all-atom empirical potentials that can satisfactorily represent the known crystal phase structures of the organic phloroglucinol (Phg) (C<sub>6</sub>H<sub>6</sub>O<sub>3</sub>) and inorganic hexachlorocyclotriphosphazene (HCCP) (N<sub>3</sub>P<sub>3</sub>Cl<sub>6</sub>) molecules at several temperatures. It has been proposed that HCCP-Phg network polymers could act as efficient H<sub>2</sub> barrier layers in hydrogen storage tanks for cars. However, essential requirements for modeling such networks are adequate representations of both monomers in their pure dense phases using a common form of force field. Tests of their ability to maintain stable crystal structures have been made using classical molecular dynamics (MD) simulations on large 800-molecule supercells. The force fields have been optimized to match the densities calculated from the experimental unit cell dimensions at ambient conditions as well as the intermolecular potential energy, as estimated from experimental enthalpies of sublimation. For Phg, the crystal structure is stabilized by a network of hydrogen bonds and the Coulombic interactions contribute to over 55% of the total intermolecular potential energy. In contrast, the crystal structure of HCCP is intrinsically stabilized by the van der Waals terms. Both optimized force fields reproduce very well the orthorhombic symmetry of their respective crystals under constant-pressure <i>N</i><b><i>P</i></b><i>T</i> conditions. The model parameters tuned at ambient temperature also give reasonable agreement with crystallographic data at lower temperatures. Phloroglucinol ; Atom (system on chip) ; Phase (matter) ; Chemistry ; Order (exchange) ; Crystal (programming language) ; Crystal structure ; Crystallography ; Computational chemistry ; Stereochemistry ; Organic chemistry ; Computer science ; Business Crystallography and molecular interactions ; Chemical Thermodynamics and Molecular Structure ; Synthesis and Properties of Aromatic Compounds
Authors: А. P. Sivokhin | D. V. Orekhov | О. А. Казанцев | Ksenia V. Otopkova | Olga Sivokhina | Ilya Chuzhaykin | Ekaterina Spitsina | Dmitry Barinov
Source: Polymers (article, 2024-12-14)
Field: Chemistry — Organic Chemistry

Anionic Oligo(ethylene glycol)-Based Molecular Brushes: Thermo- and pH-Responsive Properties Anionic thermo- and pH-responsive copolymers were synthesized by photoiniferter reversible addition-fragmentation chain transfer polymerization (PI-RAFT). The thermo-responsive properties were provided by oligo(ethylene glycol)-based macromonomer units containing hydrophilic and hydrophobic moieties. The pH-responsive properties were enabled by the addition of 5-20 mol% of strong (2-acrylamido-2-methylpropanesulfonic) and weak (methacrylic) acids. Upon initiation by visible light at 470 nm and in the absence of radical initiators, yields from the ternary copolymers reached 94% in 2.5 h when the process was carried out in continuous flow mode using 4-cyano-4-[(dodecylsulfanylthiocarbonyl)sulfanyl]pentanoic acid as a light-sensitive RAFT agent. The polymers were characterized using size exclusion chromatography, IR and NMR spectroscopy, and differential scanning calorimetry. The copolymers featured a sufficiently high molecular weight (93-146 kDa) consistent with theoretical values and satisfactory dispersities in the range of 1.18-1.45. The pH-responsive properties were studied in deionized water, saline, and buffer solutions. Dramatic differences in LCST behavior were observed in strong and weak acid-based polyelectrolytes. The introduction of sulfonic acid units, even in very small amounts, completely suppressed the LCST transition in deionized water while maintaining it in the saline and buffer solutions, with a negligible LCST dependence on the pH. In contrast, the incorporation of weak methacrylic acid demonstrated a pronounced pH dependence. The peculiarities of micelle formation in aqueous solutions were investigated and critical micelle concentrations and their ability to retain pyrene, a hydrophobic drug model, were determined. It was observed that anionic molecular brushes formed small micelles with aggregation numbers of 1-2 at concentrations in the order of 10<sup>-4</sup> mg/mL. These micelles have a high ability to entrap pyrene, which makes them a promising tool for targeted drug delivery. Lower critical solution temperature ; Polymer chemistry ; Copolymer ; Ethylene glycol ; Raft ; Critical micelle concentration ; Methacrylic acid ; Chain transfer ; Chemistry ; Micelle ; Methacrylate ; Polymerization ; Polyelectrolyte ; Polymer ; Aqueous solution ; Radical polymerization ; Organic chemistry Advanced Polymer Synthesis and Characterization ; Polymer Surface Interaction Studies ; Photopolymerization techniques and applications
Authors: Christian Tanner | Vivian R. K. Wall | Joshua Portner | Ahhyun Jeong | Avishek Das | James K. Utterback | Leo M. Hamerlynck | Jonathan G. Raybin | Matthew J. Hurley | Nicholas Leonard | Rebecca B. Wai | Jenna A. Tan | Mumtaz Gababa | Chenhui Zhu | Eric Schaible | Christopher J. Tassone | David T. Limmer | Samuel W. Teitelbaum | Dmitri V. Talapin | Naomi S. Ginsberg
Source: arXiv (Cornell University) (preprint, 2024-04-25)
Field: Materials Science — Materials Chemistry

Enhancing nanoscale charged colloid crystallization near a metastable liquid binodal Bottom-up assembly of nanocrystals (NCs) into ordered arrays, or superlattices (SLs), is a promising route to design materials with new functionalities, but the degree of control over assembly into functional structures remains challenging. Using electrostatics, rather than density, to tune the interactions between semiconductor NCs, we watch self-assembly proceeding through a metastable liquid phase. We systematically investigate the phase behavior as a function of quench conditions in situ and in real time using small angle X-ray scattering (SAXS). Through quantitative fitting to colloid, liquid, and SL models, we extract the time evolution of each phase and the system phase diagram, which we find to be consistent with short-range attractive interactions. Using the phase diagram's predictive power, we establish control of the self-assembly rate over three orders of magnitude, and identify one- and two-step self-assembly regimes, with only the latter implicating the metastable liquid as an intermediate. Importantly, the presence of the metastable liquid increases SL formation rates relative to the equivalent one-step pathway, and SL order counterintuitively increases with the rate, revealing a highly desirable and generalizable kinetic strategy to promote and enhance ordered assembly. Binodal ; Superlattice ; Metastability ; Nanocrystal ; Self-assembly ; Materials science ; Condensed matter physics ; Nanotechnology ; Crystallography ; Physics ; Phase diagram ; Chemistry ; Optoelectronics Pickering emulsions and particle stabilization ; Biocrusts and Microbial Ecology
Authors: Yiming Yao | Hong Lin | Shali Cai | Xiaodi Yang | Xike Gao
Source: Organic Chemistry Frontiers (article, 2024-01-01)
Field: Materials Science — Materials Chemistry

Single-bond-linked and vinylene-bridged azulenyl bis(squaraine) dyes: design, synthesis and molecular self-assembly behaviors Near-Infrared single-bond-linked and vinylene-bridged azulenyl bis(squaraine) dyes were synthesized. Their self-assembly behaviors were investigated under different solvent polarities, compound concentrations and temperatures. Chemistry ; Photochemistry Porphyrin and Phthalocyanine Chemistry ; Photochromic and Fluorescence Chemistry ; Molecular Sensors and Ion Detection
Authors: Daria Grigorash | Simon Müller | Patrice Paricaud | Erling H. Stenby | Ирина Смирнова | Wei Yan
Source: arXiv (Cornell University) (preprint, 2024-06-07)
Field: Chemistry — Inorganic Chemistry

A comprehensive approach to incorporating intermolecular dispersion into the openCOSMO-RS model. Part 1: Halocarbons The COSMO-RS (Conductor-like Screening Model for Real Solvents) is a predictive thermodynamic model that has found diverse applications in various domains like chemical engineering, environmental chemistry, nanotechnology, material science, and biotechnology. Its core concept involves calculating the screening charge density on the surface of each molecule and letting these surface patches interact with each other to calculate thermodynamic properties. In this study, we aim to enhance the performance of the open-source implementation openCOSMO-RS by incorporating dispersive interactions between the paired segments. Several parametrizations were systematically evaluated through the extensive regression analysis using a comprehensive database of Vapor-Liquid Equilibrium (VLE), Liquid-Liquid Equilibrium (LLE) and Infinite Dilution Activity Coefficients (IDACs). Furthermore, the influence of different combinatorial terms on the model performance was investigated. Our findings indicate that incorporating dispersive interactions significantly improves the accuracy of phase equilibrium predictions for halocarbons and refrigerant mixtures. Intermolecular force ; Dispersion (optics) ; Environmental science ; Chemistry ; Computational chemistry ; Physics ; Organic chemistry ; Quantum mechanics ; Molecule Zeolite Catalysis and Synthesis ; Phase Equilibria and Thermodynamics ; Advanced Chemical Physics Studies
Authors: Frederik Peschke | Andrea Taladriz‐Sender | Allan J. B. Watson | Glenn A. Burley
Source: Bioconjugate Chemistry (article, 2024-10-10)
Field: Chemistry — Organic Chemistry

Reactivity Profiling for High-Yielding Ynamine-Tagged Oligonucleotide Click Chemistry Bioconjugations The Cu-catalyzed azide-alkyne cycloaddition (CuAAC) reaction is a key ligation tool used to prepare bioconjugates. Despite the widespread utility of CuAAC to produce discrete 1,4-triazole products, the requirement of a Cu catalyst can result in oxidative damage to these products. Ynamines are superior reactive groups in CuAAC reactions and require lower Cu loadings to produce 1,4-triazole products. This study discloses a strategy to identify optimal reaction conditions for the formation of oligodeoxyribonucleotide (ODN) bioconjugates. First, the surveying of reaction conditions identified that the ratio of Cu to the choice of reductant (i.e., either sodium ascorbate or glutathione) influences the reaction kinetics and the rate of degradation of bioconjugate products. Second, optimized conditions were used to prepare a variety of ODN-tagged products and ODN-protein conjugates and compared to conventional CuAAC and Cu-free azide-alkyne (3 + 2)cycloadditions (SPAAC), with ynamine-based examples being faster in all cases. The reaction optimization platform established in this study provides the basis for its wider utility to prepare CuAAC-based bioconjugates with lower Cu loadings while maintaining fast reaction kinetics. Chemistry ; Bioconjugation ; Click chemistry ; Cycloaddition ; Combinatorial chemistry ; Oligonucleotide ; Triazole ; Alkyne ; Reactivity (psychology) ; Catalysis ; Kinetics ; Azide ; Organic chemistry ; Biochemistry ; DNA Click Chemistry and Applications ; Chemical Synthesis and Analysis ; Peptidase Inhibition and Analysis
Authors: Saadet Hançe | Diğdem Erdener | Berfin Ilayda Öztürk | Elif Akhüseyin Yıldız | Ahmet Karatay | Bahadır Boyacıoğlu | Hüseyin Ünver | Açelya Yılmazer | Mustafa Yıldız | Ayhan Elmalı
Source: ChemistrySelect (article, 2024-10-28)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Exploring Charge Transfer Mechanisms in Schiff Base‐Modified N‐Doped GQDs: Insights from DFT and Pump‐Probe Spectroscopy for Bioimaging Applications Abstract In recent developments, graphene quantum dots (GQDs) have emerged as valuable tools for imaging and biosensing. Various modifications on the GQDs with any desired functionality and attachment of organic molecules and/or nanostructures allow tuning their photophysical properties as well as charge transfer dynamics for bioimaging applications. This study focuses on synthesizing and characterizing of polyethyleneimine‐functionalized nitrogen‐doped GQDs ( NC1 ), Schiff base‐ functionalized nitrogen‐doped GQDs ( NC2 ), and silver nanocomposites of these Schiff base‐functionalized nitrogen‐doped GQDs ( NC3 ). We explore their absorption and emission properties to understand their interactions in the ground state. Furthermore, ultrafast transient absorption spectroscopy measurements reveal that the presence of NC3 shortens the excited state lifetime of NC1 due to charge transfer, resulting in reduced fluorescence intensity. Both experimental and DFT results suggest the potential of NC3 for bioimaging and sensing applications, making them promising candidates for phototheranostic purposes. Schiff base ; Spectroscopy ; Doping ; Materials science ; Nanotechnology ; Charge (physics) ; Chemistry ; Photochemistry ; Polymer chemistry ; Optoelectronics ; Physics Nonlinear Optical Materials Research ; Luminescence and Fluorescent Materials ; Organic Light-Emitting Diodes Research
Authors: Samira Amiri Khoshkar Vandani | Qianwei Liu | Yuki Lam | Hai‐Feng Ji
Source: Polymers (article, 2024-08-22)
Field: Chemistry — Analytical Chemistry

Enhancing Selectivity with Molecularly Imprinted Polymers via Non-Thermal Dielectric Barrier Discharge Plasma Molecularly imprinted polymers (MIPs) are synthetic polymers that mimic the functions of antibodies. Though MIPs are promising tools in various areas, achieving high selectivity in MIPs can be difficult. To improve selectivity, various approaches have been implemented; however, the role of polymerization methods or synthetic techniques in enhancing the selectivity of MIPs has not been studied and remains a crucial area for further research. MIPs are typically prepared from free radical reactions. Recently, we found that Dielectric Barrier Discharge (DBD) plasma can be used to initiate the polymerization of vinyl monomers. The DBD plasma method allows the monomers to associate with the template molecules and initiate polymerization with minimal disruption to the positioning of the monomers. We hypothesize that this could be a preferred method to prepare MIPs over the traditional radical reaction that may cause a disturbance of the pre-associated monomers on the templates for the polymerization. Chicken egg white serum albumin (CESA) was used as the template protein for the MIPs. Our results show that in all test conditions, approximately twofold improvement in selectivity was achieved, which is the primary performance metric for MIPs. This enhancement was evident across all categories, including MIPs prepared from various monomer combinations. Molecularly imprinted polymer ; Selectivity ; Monomer ; Polymerization ; Polymer ; Dielectric barrier discharge ; Materials science ; Chemical engineering ; Polymer chemistry ; Chemistry ; Organic chemistry ; Dielectric ; Catalysis Analytical chemistry methods development ; Plasma Applications and Diagnostics ; Mass Spectrometry Techniques and Applications
Authors: Asha Asha | K.C. Juglan | Alok Jain
Source: AIP conference proceedings (review, 2024-01-01)
Field: Materials Science — Materials Chemistry

A review on magnetic properties, synthesis, characterization, and applications of Mn-Ni Fe2O4 ferrites Due to its numerous uses in a variety of fields, researchers are very interested in the study of characterization and synthesis of Mn-Ni ferrites. A group of soft magnetic materials called Mn-Ni ferrites have excellent electrical, magnetic, and optical characteristics. High coercivity, saturation magnetization, permeability, permittivity, resistivity, low power losses, and permeability values are among the characteristics of Mn-Ni ferrites. Mn-Ni ferrites are useful because of their usage in different fields. These ferrites are useful in the biomedical area, in transducers, in electronic applications, transformers, and in inductors are all made using Mn-Ni ferrites. Additionally, magnetic fluids, sensors, and biosensors utilize these ferrites. Materials science ; Coercivity ; Inductor ; Permeability (electromagnetism) ; Permittivity ; Characterization (materials science) ; Ferrite (magnet) ; Nuclear magnetic resonance ; Optoelectronics ; Dielectric ; Condensed matter physics ; Composite material ; Electrical engineering ; Nanotechnology ; Voltage ; Chemistry Magnetic Properties and Synthesis of Ferrites ; Characterization and Applications of Magnetic Nanoparticles ; Advancements in Battery Materials
Authors: María José Vázquez Bernárdez | N. Vukadinovic | Christophe Lefèvre | D. Stoeffler
Source: ACS Applied Electronic Materials (article, 2024-04-24)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Tuning Dynamic Susceptibility in Barium Hexaferrite Core–Shell Nanoparticles through Size-Dependent Resonance Modes M-type hexagonal ferrites present compelling prospects for the design of high-performance multifunctional absorbers operating within the Ku, K, and Ka frequency ranges, spanning 12 to 40 GHz at a zero-applied magnetic field. While it is widely acknowledged that the operational frequency of this compound can be manipulated through chemical substitution, the ongoing challenge lies in achieving precise control over the absorption bandwidth via the spectral line width of its dynamic susceptibility. For this purpose, we investigate by means of micromagnetic simulations core–shell nanoparticles with an M-type hexagonal ferrite shell grown on top of a nonmagnetic core. This configuration allows the modulation of the number and the frequency of the resonance modes only by controlling the thickness and the size of the ferrite magnetic shell. This phenomenon is produced at microwave frequencies for relatively large particles (external diameter from 150 to 500 nm) and produces supplementary resonance peaks at amplitudes comparable to the main ferromagnetic mode of a solid sphere. The study of the magnetization dynamics of these size-dependent modes confirmed their nature as essentially exchange resonance modes. The limitations of available analytical models for describing the behavior of such modes in hollow spheres are highlighted. As for most commercial applications, these properties are present at a zero-applied magnetic field, and the simulations performed evidence that the system is resistant to experimental deviations. Ferromagnetic resonance ; Barium ferrite ; Materials science ; Resonance (particle physics) ; Ferrite (magnet) ; Condensed matter physics ; SPHERES ; Magnetization ; Coercivity ; Amplitude ; Microwave ; Nuclear magnetic resonance ; Magnetic field ; Physics ; Optics ; Composite material ; Atomic physics Electromagnetic wave absorption materials ; Magnetic Properties and Synthesis of Ferrites ; Advanced Antenna and Metasurface Technologies
Authors: Jan Radolko | Ha Minh Tuan | Ricardo Molenda | Alexander Villinger | Peter Ehlers | Peter Langer
Source: Chemistry - A European Journal (article, 2024-09-30)
Field: Chemistry — Organic Chemistry

N‐doped and Bowl‐Shaped Azabenzo[3,4]azulenofluorene: Synthesis and Characterization of Bridged Aza‐Triarylamines Triarylamines are frequently employed as electron donor functional groups in a variety of organic electronic materials. We herein report the synthesis and in-depth characterisation of aza-analogues of fully bridged triarylamines, consisting of 5-, 6- and 7-membered rings. The impact of nitrogen doping and π-extension on the structural, electronic and optical-properties of these contorted heteroaromatic PAHs is thoroughly investigated and paves the way for an improved understanding of the structure-property relationships. Characterization (materials science) ; Doping ; Materials science ; Chemistry ; Combinatorial chemistry ; Nanotechnology ; Optoelectronics Synthesis and Properties of Aromatic Compounds ; Luminescence and Fluorescent Materials ; Organic Electronics and Photovoltaics