jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Anastassia N. Rissanou | Apostolos Konstantinou | K. Karatasos
Source: Nanomaterials (article, 2023-06-15)
Field: Materials Science — Materials Chemistry

Morphology and Dynamics in Hydrated Graphene Oxide/Branched Poly(ethyleneimine) Nanocomposites: An In Silico Investigation Graphene oxide (GO)-branched poly(ethyleneimine) (BPEI) hydrated mixtures were studied by means of fully atomistic molecular dynamics simulations to assess the effects of the size of polymers and the composition on the morphology of the complexes, the energetics of the systems and the dynamics of water and ions within composites. The presence of cationic polymers of both generations hindered the formation of stacked GO conformations, leading to a disordered porous structure. The smaller polymer was found to be more efficient at separating the GO flakes due to its more efficient packing. The variation in the relative content of the polymeric and the GO moieties provided indications for the existence of an optimal composition in which interaction between the two components was more favorable, implying more stable structures. The large number of hydrogen-bonding donors afforded by the branched molecules resulted in a preferential association with water and hindered its access to the surface of the GO flakes, particularly in polymer-rich systems. The mapping of water translational dynamics revealed the existence of populations with distinctly different mobilities, depending upon the state of their association. The average rate of water transport was found to depend sensitively on the mobility of the freely to move molecules, which was varied strongly with composition. The rate of ionic transport was found to be very limited below a threshold in terms of polymer content. Both, water diffusivity and ionic transport were enhanced in the systems with the larger branched polymers, particularly with a lower polymer content, due to the higher availability of free volume for the respective moieties. The detail afforded in the present work provides a new insight for the fabrication of BPEI/GO composites with a controlled microstructure, enhanced stability and adjustable water transport and ionic mobility. Polymer ; Oxide ; Ionic bonding ; Materials science ; Molecular dynamics ; Chemical engineering ; Molecule ; Hydrogen bond ; Chemical physics ; Nanocomposite ; Cationic polymerization ; Graphene ; Polymer chemistry ; Ion ; Chemistry ; Nanotechnology ; Computational chemistry ; Organic chemistry ; Composite material Graphene research and applications ; Membrane Separation and Gas Transport ; Nanopore and Nanochannel Transport Studies
Authors: N. Hasan | S. S. Nishat | S. Sadman | M. R. Shaown | M. A. Hoquee | M. Arifuzzaman | A. Kabir
Source: arXiv (Cornell University) (preprint, 2023-01-26)
Field: Materials Science — Materials Chemistry

Magnetic, Optoelectronic, and Rietveld refined structural properties of Al3+ substituted nanocrystalline Ni-Cu spinel ferrites: An experimental and DFT based study The nanocrystalline Ni0.7Cu0.3AlxFe2-xO4 (x=0.00: 0.02: 0.10) is prepared through the sol-gel autocombustion route.Both XRD and Rietveld confirm the single-phase cubic spinel structure of the investigated materials.Other structural parameters refined by the Rietveld refinement analysis are corroborated to single-phase cubic spinel formation of the NPs.Leveraging a vibrating sample magnetometer (VSM) the consequence of Al3+ substitution on the magnetic parameters is studied.The saturation magnetization (MS) and Bohr magneton are found to decrease with Al3+ substitution.The Remanence ratio and coercivity (HC) are observed to be very low suggesting the materials are soft ferromagnetic.First-principle calculations were carried out using the density functional theory (DFT) to demonstrate the optoelectronic behavior of the materials.The electronic bandgap is found low as Eg=2.99eV for the explored materials with observing defect states at 0.62eV.The optoelectronic properties of Al3+ substituted Ni-Cu ferrite NPs have been characterized through the DFT simulation for the first time, demonstrating their potentiality for optoelectronic device applications.The materials' optical anisotropy is observed along the x-axis, which manifests their tunability through light-matter interaction. Rietveld refinement ; Materials science ; Nanocrystalline material ; Spinel ; Coercivity ; Remanence ; Density functional theory ; Bohr magneton ; Ferromagnetism ; Band gap ; Ferrite (magnet) ; Condensed matter physics ; Magnetization ; Magnetic moment ; Analytical Chemistry (journal) ; Crystallography ; Nanotechnology ; Optoelectronics ; Crystal structure ; Metallurgy ; Computational chemistry ; Chemistry ; Physics ; Magnetic field ; Composite material Magnetic Properties and Synthesis of Ferrites ; Magnetic properties of thin films ; Magnetic Properties and Applications
Authors: Rocío Donamaría | Vito Lippolis | José M. López‐de‐Luzuriaga | Miguel Monge | M. Elena Olmos
Source: ChemPlusChem (article, 2023-11-07)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Heteronuclear Gold(I)‐Copper(I) Complexes with Thia‐ and Mixed Thia‐Aza Macrocyclic Ligands: Synthesis, Structures and Optical Properties The reactivity of the heterometallic polynuclear complexes [{Au(R)<sub>2</sub> }<sub>2</sub> Cu<sub>2</sub> (MeCN)<sub>2</sub> ]<sub>n</sub> (R=C<sub>6</sub> F<sub>5</sub> , C<sub>6</sub> Cl<sub>5</sub> ) with the thioether crowns 1,4,7-trithiacyclononane (L1, [12]aneS<sub>3</sub> ), 1,4,8,11-tetrathiacyclododecane (L2, [14]aneS<sub>4</sub> ), 1,4,7,10,13,16,19,22-octathiacyclotetracosane (L3, [24]aneS<sub>8</sub> ), and the quinoline functionalized pendant arm derivatives of the 12-membered mixed-donor macrocycles 1-aza-,4,7,10-trithiacyclododecane ([12]aneNS<sub>3</sub> ) and 1,7-diaza-4,10-dithiacyclododecane ([12]aneN<sub>2</sub> S<sub>2</sub> ), L4 and L5, respectively, was investigated in THF solution. While with L4 and L5 only ionic compounds of general formulation [Cu(L)][Au(R)<sub>2</sub> ] were isolated and structurally characterized (none of them featuring Au⋅⋅⋅Cu interactions), with L1-L3, beside similar ionic compounds, some heteronuclear complexes of general formulation [{Au(R)<sub>2</sub> }{Cu(L)}] and featuring Au⋅⋅⋅Cu interactions were also obtained. All of them display rather unusual non-classical C-H⋅⋅⋅Au hydrogen interactions. The complexes display in the solid state different optical properties related to their structures, which have been studied experimentally and theoretically via TD-DFT calculations. In particular, all compounds of the type [{Au(R)<sub>2</sub> }{Cu(L)}] featuring Au⋅⋅⋅Cu metallophilic interactions display luminescence in the solid state both at room temperature (RT) and at 77 K. On the contrary, ionic compounds of general formulation [Cu(L)][Au(R)<sub>2</sub> ], except [Cu(L4)][Au(C<sub>6</sub> F<sub>5</sub> )<sub>2</sub> ], are not luminescent. Heteronuclear molecule ; Copper ; Chemistry ; Combinatorial chemistry ; Polymer chemistry ; Nanotechnology ; Molecule ; Materials science ; Organic chemistry Magnetism in coordination complexes ; Metal complexes synthesis and properties ; Nanocluster Synthesis and Applications
Authors: Hanna K. Maliszewska | Mahmoud A. S. Abdelhamid | María J. Marín | Zoë A. E. Waller | María Paz Muñoz
Source: Pure and Applied Chemistry (article, 2023-04-01)
Field: Chemistry — Organic Chemistry

Anticancer activity and DNA interaction of bis(pyridyl)allene-derived metal complexes Abstract The constant need for novel drugs has prompted the scientific community to explore alternative structures to natural products and small and medium size organic compounds used in classic medicinal and pharmaceutical chemistry. Since the discovery of cisplatin, organometallic compounds have revealed great potential as metallodrugs and their development has exponentially grown in recent years. In this manuscript, we describe our efforts towards the synthesis of new metallodrugs by reaction of bis(pyridyl)allenes and metal complexes. Two classes of compounds are presented: one in which the allene structure is intact and the metal (Pd(II), Pt(IV) or Au(III)) coordinates to the pyridine-nitrogens; and another, in which one of the pyridines cyclises into a gold-activated allene to form β-N-stabilised gold carbenes. Both classes of compounds are active catalysts in important organic reactions, and are also promising antimicrobial, antifungal and anticancer agents. In this work, we describe the promising anticancer activity, against breast cancer cells, of the gold carbene complexes, and preliminary studies of their interaction with DNA, including non-canonical DNA structures. Our results have revealed an unusual selective stabilisation of hTeloC i-motif by one of the Au(III) carbene complexes, that opens up exciting opportunities for further development of novel DNA-binding metallodrugs. Chemistry ; Allene ; Carbene ; Gold Compounds ; Combinatorial chemistry ; Pyridine ; DNA ; Metal ; Stereochemistry ; Nanotechnology ; Organic chemistry ; Catalysis ; Biochemistry Catalytic Alkyne Reactions ; Metal complexes synthesis and properties ; Ferrocene Chemistry and Applications
Authors: G. Sai Teja | D. Archana | B. Srinu | SK. Abbas Ali | S. Siva Narayana Reddy | SK. Parvez | P. Srinivasa Babu | P. Ravi Sankar
Source: International Journal of Pharmaceutical Sciences Review and Research (article, 2023-10-01)
Field: Chemistry — Analytical Chemistry

A Comprehensive Guide for Analytical Method Validation Analytical method validation is a crucial process that provides documented evidence of the suitability, accuracy, specificity, and precision of a test procedure for its intended purpose.This paper aims to summarize the requirements of method validation and data generation necessary to establish the reliability and performance of the analytical method.It emphasizes the importance of conducting validation for new analysis methods as well as when modifications are made to the procedure, drug product composition, or drug substance synthesis.Adhering to the guidelines set by the International Council for Harmonisation (ICH) and various pharmacopeia, critical validation parameters are discussed to ensure comprehensive validation before employing the method for release or stability testing.This review also covers optimization techniques, and factors influencing chromatography method validation, and provides an overview of relevant definitions and formulas.Through method validation, the analytical method's suitability for its intended use is demonstrated, ultimately contributing to the overall quality control and assurance of analytical results. Computer science Analytical Methods in Pharmaceuticals ; Spectroscopy and Chemometric Analyses ; Analytical Chemistry and Chromatography
Authors: Yingying Guo | Linqing Bai
Source: Polymers (article, 2023-10-03)
Field: Materials Science — Materials Chemistry

Dissipative Particle Dynamics Simulation for the Self-Assembly of Symmetric Pentablock Terpolymers Melts under 1D Confinements The phase behavior of CBABC pentablock terpolymers confined in thin films is investigated using the Dissipative Particle Dynamic method. Phase diagrams are constructed and used to reveal how chain length (i-block length), block composition and wall selectivity influence the self-assembly structures. Under neutral walls, four categories of morphologies, i.e., perpendicular lamellae, core-shell types of microstructures, complex networks, and half-domain morphologies, are identified with the change in i-block length. Ordered structures are more common at weak polymer-polymer interaction strengths. For polymers of a consistent chain length, when one of the three components has a relatively smaller length, the morphologies transition is sensitive to block composition. With selective walls, parallel lamellae structures are prevalent. Wall selectivity also impacts chain conformations. While a large portion of chains form loop conformations under A-selective walls, more chains adopt bridge conformation when the wall prefers C-blocks. These findings offer insights for designing nanopatterns using symmetric pentablock terpolymers. Dissipative particle dynamics ; Dissipative system ; Materials science ; Particle (ecology) ; Molecular dynamics ; Dynamics (music) ; Particle dynamics ; Chemical physics ; Polymer science ; Composite material ; Physics ; Polymer ; Thermodynamics ; Geology Block Copolymer Self-Assembly ; Advanced Polymer Synthesis and Characterization ; Polymer Surface Interaction Studies
Authors: Wei Shu | Ming‐Shang Liu | Huan Meng
Source: ChemRxiv (preprint, 2023-07-03)
Field: Chemistry — Organic Chemistry

Unified Metal-Free Intermolecular Heck-Type Sulfonylation, Cyanation, Amination, Amidation of Alkenes by Thianthrenation Direct and site-selective C-H functionalization of alkenes under environmentally benign conditions represents a useful and attractive yet challenging transformation to access value-added molecules. Herein, a unified protocol for a variety of intermolecular Heck-type functionalizations of Csp2-H bond of alkenes has been developed by thianthrenation for the first time. The reaction features metal-free and operationally simple conditions for exclusive cine-selective C-H functionalization of aliphatic and aryl alkenes to forge C-C, C-N, and C-S bonds at room temperature, providing a general protocol for intermolecular Heck-type reaction of alkenes with nucleophiles (Nu = sulfinates, cyanides, amines, amides). Alkenes undergo cine-sulfonylation, cyanation, amination to afford alkenyl sulfones, alkenyl nitriles and enamines. Cyanation ; Amination ; Chemistry ; Intermolecular force ; Heck reaction ; Aryl ; Surface modification ; Combinatorial chemistry ; Organic chemistry ; Nucleophile ; Palladium ; Molecule ; Catalysis Sulfur-Based Synthesis Techniques ; Catalytic C–H Functionalization Methods ; Synthesis and Catalytic Reactions
Authors: Martin Traintinger | Roman Christopher Kerschbaumer | Michaela Hornbachner | Bernhard Lechner | Thomas Lucyshyn
Source: Journal of Applied Polymer Science (article, 2023-11-20)
Field: Materials Science — Polymers and Plastics

Investigation on strategies for optimizing process definition in rubber processing: A study on mechanical and chemical properties of vulcanizates as basis for the development of a new calculation model for quality prediction Abstract Rubber compounds may exhibit significant batch variations due to multiple different ingredients mixed in one compound. Hence, defining the manufacturing process for constant part quality can be challenging. Common strategies in considering batch variations in rubber processing include the determination of reaction kinetics, and the definition of process parameters according to normalized vulcanization isotherms. Thereby, maintenance of the degree of cure is targeted. With this path, information on the mechanical properties of vulcanizates is lost, despite its visibility from the kinetic data and part quality assurance is missed. This contribution points out the differences obtained for parts produced to the same degree of cure at various temperatures and intends to emphasize new strategies in process definitions. Therefore, compression molded parts were produced from styrene‐butadien rubber, which was then characterized with mechanical and chemical methods. Each of the methods revealed a significant difference in part behavior, which were manufactured to the same degrees of cure but at different temperatures. It was concluded that a temperature‐dependent reaction rate should be considered when quality maintenance is targeted in the production. Only then will it be possible to predict the properties adequately, with simultaneous effect of enhancing sustainability policies in rubber processing. Natural rubber ; Vulcanization ; Process (computing) ; Process engineering ; Materials science ; Quality (philosophy) ; Computer science ; Biochemical engineering ; Polymer science ; Composite material ; Engineering ; Physics Polymer Nanocomposites and Properties ; Polymer crystallization and properties ; Epoxy Resin Curing Processes
Authors: Julia Arnanz | Fernando Romeo‐Gella | Juan J. Nogueira | Inés Corral
Source: Dyes and Pigments (article, 2023-07-19)
Field: Materials Science — Materials Chemistry

In silico investigation of the photoisomerization mechanism of push-push azoderivatives The design of novel chromophores showing specific photophysical traits is nowadays crucial for the development of new dyes and optical devices. Azobenzene derivatives comprise the largest fraction of the industrial dyes and remain one of the main functions to be employed in the design of general-purpose photoactivated switches. In this context, we have investigated the optical and photoisomerization properties of two push-push azo derivatives, from a purely theoretical perspective, to outline a mechanistic landscape that can contribute to setting the grounds for the future goal of formulating dyes with particular photophysical properties. Both derivatives show downhill excited-state potential energy surfaces, hinting at fast photoactivated isomerization. In addition, both the trans and cis forms show nearly complementary absorption spectra leading to discriminatory color and differential excitation possibilities. Additionally, the reverse cis to trans ground state thermal isomerization reactions show higher energy barriers than the parent azobenzene molecule, supporting their potential use in different technological applications. Photoisomerization ; Isomerization ; Chromophore ; Azobenzene ; Context (archaeology) ; Photochemistry ; Excited state ; Chemistry ; Molecular switch ; Molecule ; Combinatorial chemistry ; Organic chemistry ; Physics Photochromic and Fluorescence Chemistry ; Radical Photochemical Reactions ; Luminescence and Fluorescent Materials
Authors: Andrey D. Denikaev | Grigory А. Кim | E. D. Greshnyakov | Nikolai Moskalenko | K. V. Grzhegorzhevskii
Source: Inorganics (article, 2023-05-30)
Field: Materials Science — Materials Chemistry

Covalent Grafting of Eosin Y to the Giant Keplerate {Mo132} through an Organosilicon Linker in Homogeneous Regime The template effect of giant polyoxometalates (POM) shows promising results towards the supramolecular design of hybrid materials suitable for photocatalytic reactions. Here, we demonstrate a novel synthetic approach for covalently grafting the xanthene dye eosin Y (EY) to the nanoscale Keplerate POM {Mo132} via an organosilicon linker (3-aminopropyltrimethoxysilane, APTMS) in a homogeneous regime. Using a phase transfer agent, tetrabutylammonium bromide, we solubilize the Keplerate POM modified with six {Si(CH2)3NH2} groups, {Mo132}@Si6, in a series of organic solvents—acetonitrile, acetone, tetrahydrofuran, and dichloromethane—to perform post-functionalization by using an NHS-ester of EY. Both IR and Raman spectroscopy affirm the preservation of the POM’s structure and showcase an amide bond formation between POM and EY in the obtained conjugate {Mo132}@Si6@EY@TBA. Grafting’s success is observed through significant downfield shifting of EY’s aromatic protons’ signals on the 1H NMR spectrum as compared to the spectra of EY and EY-NHS. The current synthetic approach enables us to exercise precise control of the stoichiometry in the POM-dye conjugates—1:1 for the POM-EY system—as confirmed by elemental analysis. Comprehensive photophysical analysis of {Mo132}@Si6@EY@TBA by means of UV-Vis and steady-state and time-resolved fluorescence measurements points to an existing strong interaction between molecular orbitals of EY and {Mo132}, leading to a photoinduced electron transfer, partial fluorescence quenching, and elongation of the excited state’s lifetime. These findings demonstrate that using APTMS as an organosilicon linker in tandem with the Keplerate POM as a nanoscale template can be readily applied as a routine synthetic procedure for grafting various organic dyes or other organic molecules bearing a carboxylic group in their structure to the giant POM surface in a variety of aprotic organic solvents. Organosilicon ; Chemistry ; Eosin Y ; Photochemistry ; Covalent bond ; Polymer chemistry ; Photocatalysis ; Organic chemistry ; Catalysis Polyoxometalates: Synthesis and Applications ; biodegradable polymer synthesis and properties ; Metal-Organic Frameworks: Synthesis and Applications
Authors: Jacopo Segato | Eleonora Aneggi | Walter Baratta | Filippo Campagnolo | Leonardo Belpassi | Paola Belanzoni | Daniele Zuccaccia
Source: Organometallics (article, 2023-09-30)
Field: Chemistry — Organic Chemistry

Experimental and Theoretical Investigation of Ion Pairing in Gold(III) Catalysts The ion pairing structure of the possible species present in solution during the gold(III)-catalyzed hydration of alkynes: [(ppy)Au(NHC)Y]X<sub>2</sub> and [(ppy)Au(NHC)X]X [ppy = 2-phenylpyridine, NHC = NHC<sup>iPr</sup> = 1,3-bis(2,6-di-isopropylphenyl)-imidazol-2-ylidene; NHC = NHC<sup>mes</sup> = 1,3-bis(2,4,6-trimethylphenyl)-imidazol-2-ylidene X = Cl<sup>-</sup>, BF<sub>4</sub><sup>-</sup>, OTf<sup>-</sup>; Y = H<sub>2</sub>O and 3-hexyne] are determined. The nuclear overhauser effect nuclear magnetic resonance (NMR) experimental measurements integrated with a theoretical description of the system (full optimization of different ion pairs and calculation of the Coulomb potential surface) indicate that the preferential position of the counterion is tunable through the choice of the ancillary ligands (NHC<sup>iPr</sup>, NHC<sup>mes</sup>, ppy, and Y) in [(ppy)Au(NHC)(3-hexyne)]X<sub>2</sub> activated complexes that undergo nucleophilic attack. The counterion can approach near NHC, pyridine ring of ppy, and gold atom. From these positions, the anion can act as a template, holding water in the right position for the outer-sphere attack, as observed in gold(I) catalysts. Chemistry ; Counterion ; Pyridine ; Catalysis ; Ion ; Pairing ; Ring (chemistry) ; Nucleophile ; Crystallography ; Inorganic chemistry ; Medicinal chemistry ; Organic chemistry Catalytic Alkyne Reactions ; Catalytic C–H Functionalization Methods ; Asymmetric Hydrogenation and Catalysis