jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: K. N. Shivakumara | B. Sridhar
Source: International Journal of Chemical Research and Development (article, 2021-01-01)
Field: Chemistry — Organic Chemistry

Review on role of urea and thiourea derivatives of some heterocyclic Scaffold in drug design and medicinal chemistry Compounds comprising urea and thiourea are progressively more used in drug design and medicinal chemistry to facilitate key drug-target communications and fine-tune crucial drug-like properties. Urea and thiourea represent privileged structures in medicinal chemistry. Certainly, these scaffolds encompass a common structure of a array of drugs and bioactive compounds artistic with a expansive range of beneficial and pharmacological properties. Herein, we provide an overview of urea and thiourea based medicinally important compounds, ranging from standard drugs to current medicinal chemistry developments. Thiourea ; Expansive ; Urea ; Chemistry ; Combinatorial chemistry ; Drug ; Scaffold ; Organic chemistry ; Pharmacology ; Materials science ; Medicine ; Biomedical engineering Synthesis and biological activity ; Click Chemistry and Applications ; Synthesis of heterocyclic compounds
Authors: Alastair J. McMillan | Martyna Sieńkowska | Piero Di Lorenzo | Gemma K. Gransbury | Nicholas F. Chilton | Michela Salamone | Alessandro Ruffoni | Massimo Bietti | Daniele Leonori
Source: Angewandte Chemie (article, 2021-01-18)
Field: Chemistry — Organic Chemistry

Practical and Selective sp<sup>3</sup>C−H Bond Chlorination via Aminium Radicals Abstract The introduction of chlorine atoms into organic molecules is fundamental to the manufacture of industrial chemicals, the elaboration of advanced synthetic intermediates and also the fine‐tuning of physicochemical and biological properties of drugs, agrochemicals and polymers. We report here a general and practical photochemical strategy enabling the site‐selective chlorination of sp 3 C−H bonds. This process exploits the ability of protonated N ‐chloroamines to serve as aminium radical precursors and also radical chlorinating agents. Upon photochemical initiation, an efficient radical‐chain propagation is established allowing the functionalization of a broad range of substrates due to the large number of compatible functionalities. The ability to synergistically maximize both polar and steric effects in the H‐atom transfer transition state through appropriate selection of the aminium radical has provided the highest known selectivity in radical sp 3 C−H chlorination. Chemistry ; Radical ; Steric effects ; Protonation ; Surface modification ; Molecule ; Selectivity ; Photochemistry ; Combinatorial chemistry ; Organic chemistry ; Catalysis Radical Photochemical Reactions ; Oxidative Organic Chemistry Reactions ; Catalytic C–H Functionalization Methods
Authors: Marrigje M. Conradie | Еrnst H.G. Langner | Jeanet Conradie
Source: Data in Brief (article, 2021-08-26)
Field: Chemistry — Organic Chemistry

DFT data to relate calculated LUMO energy with experimental reduction potentials of Cu(II)-β-diketonato complexes We present data on the computed lowest unoccupied molecular orbital energy (<i>E<sub>LUMO</sub></i> ) of two series of Cu(II)-β-diketonato complexes, calculated via density functional theory (DFT). These are correlated to experimental reduction potential data (<i>E</i> <sub>pc</sub>), obtained by cyclic voltammetry under different experimental conditions (solvent, working and reference electrodes). All calculations were done with the B3LYP functional in the gas phase. Knowledge of the influence of different ligands on the redox potential of copper complexes, as measured by DFT calculated energy data, are very useful. These theoretical correlations are vital in the further design of similar compounds, to be customized for specific applications. The correlations can be used to predict and fine-tune redox potentials prior to synthesis, saving experimental chemists time and laboratory expenses. Redox potentials influence the catalytic property of bis(β-diketonato)copper(II) compounds. New catalysts can therefore be customized with a specific reduction potential and catalytic activity. Further, the Cu(II/I) redox couple is a potential alternative as electrolyte for dye-sensitized solar cells [1], [2], [3]. The redox potential of the electrolyte can drastically affect the photovoltage output and should therefore be optimized for efficiency and durability. By adjusting the reduction potential via different ligands on the complex, the properties of copper dyes can be fine-tuned at molecular level. For more insight into the reported data, see the related research article "Synthesis, Characterization, DFT and Biological Activity of Oligothiophene β-diketone and Cu-complexes" published in Polyhedron [4]. Redox ; HOMO/LUMO ; Density functional theory ; Electrolyte ; Chemistry ; Copper ; Catalysis ; Cyclic voltammetry ; Supporting electrolyte ; Computational chemistry ; Physical chemistry ; Molecule ; Inorganic chemistry ; Electrochemistry ; Electrode ; Organic chemistry Free Radicals and Antioxidants ; Photochemistry and Electron Transfer Studies ; Porphyrin and Phthalocyanine Chemistry
Authors: Paulo R. A. F. Garcia | W. W. R. Araújo | Gabriel Braga Marques Teobaldo | Alan Silva de Menezes | Larissa Otubo | Cristiano L. P. Oliveira
Source: International nano letters. (article, 2021-01-18)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Synthesis and structural characterization of gold nanorods Nanorod ; Materials science ; Characterization (materials science) ; Nanochemistry ; Dynamic light scattering ; Transmission electron microscopy ; Spectroscopy ; Nanotechnology ; Scattering ; Diffraction ; Chemical engineering ; Optics ; Nanoparticle ; Physics Gold and Silver Nanoparticles Synthesis and Applications ; Nanocluster Synthesis and Applications ; Electrochemical Analysis and Applications
Authors: Fabian Matter | Markus Niederberger | Florian Putz
Source: CHIMIA International Journal for Chemistry (article, 2021-05-21)
Field: Materials Science — Materials Chemistry

Colloidal Nanocrystals: A Toolbox for Materials Chemistry Colloidal nanocrystals are the ideal building blocks for the fabrication of functional materials. Using various assembly, patterning or processing techniques, the nanocrystals can be arranged with unprecedented flexibility in 1-, 2- or 3-dimensional architectures over several orders of length scales, providing access to ordered or disordered, porous or non-porous, and simple as well as hierarchical structures. Careful selection of colloidal nanocrystals allows the properties of the final materials to be predefined. Moreover, by combining different nanocrystals, these properties can be fine-tuned for a specific application, opening up fascinating opportunities to create new materials for energy storage and conversion, catalysis, photocatalysis, biomedicine or optics. Indeed, functional materials made of preformed nanoparticles have been realized for metals, polymers, semiconductors, and ceramics, as well as for composites and organic-inorganic hybrids. In this review article, we introduce some concepts for the fabrication of colloidal nanocrystals and their assembly into dense and porous 3-dimensional structures. Porosity is a particularly important material property that strongly influences its application potential. Therefore, we pay special attention to this aspect and compare porous materials synthesized from nanoparticles with those from molecular routes. An additional focus is set on the degree of structural order that can be achieved on different length scales. Nanocrystal ; Nanotechnology ; Fabrication ; Materials science ; Porosity ; Nanoparticle ; Flexibility (engineering) ; Polymer ; Colloid ; Chemistry ; Composite material Quantum Dots Synthesis And Properties ; Advanced Nanomaterials in Catalysis ; Advanced Photocatalysis Techniques
Authors: Sneha Choudhury | Ronny Golnak | Christian Schulz | Klaus Lieutenant | N. Tranchant | Jean‐Charles Arnault | M.A. Pinault-Thaury | François Jomard | Peter Knittel | Tristan Petit
Source: C – Journal of Carbon Research (article, 2021-03-09)
Field: Materials Science — Materials Chemistry

Impact of Nitrogen, Boron and Phosphorus Impurities on the Electronic Structure of Diamond Probed by X-ray Spectroscopies Doping diamond with boron, nitrogen or phosphorus enables a fine tuning of its electronic properties, which is particularly relevant for applications involving electron emission. However, the chemical nature of the doping sites and its correlation with electron emission properties remain to be clarified. In this work, we applied soft X-ray spectroscopy techniques to probe occupied and unoccupied electronic states in undoped, boron-, phosphorus- and nitrogen-containing single crystal diamonds. X-ray absorption, X-ray emission and X-ray photoemission spectroscopies, performed at the carbon K-edge, provide a full picture of new electronic states created by impurities in diamond. The different probing depths of fluorescence- and electron-based detection techniques enable a comparison between surface and bulk contributions. Diamond ; Boron ; Impurity ; Materials science ; X-ray photoelectron spectroscopy ; Nitrogen ; Carbon fibers ; X-ray spectroscopy ; Analytical Chemistry (journal) ; Phosphorus ; Doping ; Spectroscopy ; Chemistry ; Optoelectronics ; Nuclear magnetic resonance ; Metallurgy ; Physics Diamond and Carbon-based Materials Research ; Ion-surface interactions and analysis ; Electronic and Structural Properties of Oxides
Authors: Tiên Hiêp Nguyên | Yu. V. Konyukhov | Nguyễn Văn Minh | D. Karpenkov | V. V. Levina | Gopalu Karunakaran | A. G. Buchirina
Source: Eurasian Chemico-Technological Journal (article, 2021-03-25)
Field: Materials Science — Materials Chemistry

Magnetic Properties of Fe, Co and Ni Based Nanopowders Produced by Chemical-Metallurgy Method This research study describes the magnetic properties of Fe, Co and Ni metallic nanopowders (NPs) and their ternary nanocomposites (NCs), which can be used as fillers in radio-wave absorbing composite materials and coatings, as well as for magnetic protection of banknotes and security paper. The nanopowders were prepared by the chemical metallurgy method. The desired properties of Fe, Co and Ni NPs and NCs were achieved by co-precipitation, the addition of surfactants and changes in reduction temperature and time parameters. Magnetic measurements showed that all samples of pure metal NPs are semi-hard magnetic materials. The added surfactants have distinct effects on the dimensional and magnetic characteristics of Fe, Co and Ni NPs. Ni–Co–Fe NCs are also mainly semi-hard magnetic materials. Fine-tuning of their composition and chemical reduction temperatures allows controlling the values of Ms and Hc in large ranges from 49 to 197 A·m2/kg and from 4.7 to 60.6 kA/m, respectively. Materials science ; Ternary operation ; Powder metallurgy ; Metal ; Metallurgy ; Nanocomposite ; Precipitation ; Chemical engineering ; Magnetic nanoparticles ; Nanoparticle ; Composite material ; Microstructure ; Nanotechnology Chemical and Physical Properties of Materials ; Electromagnetic wave absorption materials ; Electrohydrodynamics and Fluid Dynamics
Authors: K. Priya | Gowrish K. Rao | A. V. Muhammed Ali | M.S. Murari | Ganesh Sanjeev
Source: Physica B Condensed Matter (article, 2021-07-03)
Field: Materials Science — Materials Chemistry

The effect of vacuum and air annealing on the structural, optical and photoluminescence properties of ZnS films Annealing (glass) ; Crystallite ; Materials science ; Ultimate tensile strength ; Photoluminescence ; Composite material ; Band gap ; Vacuum deposition ; Ultra-high vacuum ; Thin film ; Optoelectronics ; Metallurgy ; Nanotechnology Quantum Dots Synthesis And Properties ; Chalcogenide Semiconductor Thin Films ; Copper-based nanomaterials and applications
Authors: Ulises A. Méndez‐Romero | Miguel Ángel Velasco‐Soto | Liliana Licea‐Jiménez | J. González‐Hernández | Sergio Alfonso Pérez‐García
Source: Nano Select (article, 2021-04-07)
Field: Materials Science — Materials Chemistry

Long‐term evolution of the chemical and structural stability of graphene oxide after storage as solid and as aqueous dispersion Abstract Nanomaterials are intended for industrial applications, for that purpose scalability needs to be addressed, therefore an important issue comes to the picture: storage. Graphene oxide (GO) is of great interest for practical applications in optoelectronics, chemical sensors, supercapacitor electrodes, among others. GO properties are related to its O/C ratio and its precise control allows fine tuning of properties such as conductivity, chemical reactivity and band gap. Nevertheless, GO has a critical storage restriction, due to its chemical self‐reduction, that is, the oxygen loss not only alters its properties, but also promotes aggregation through time. In this work, the impact of storage conditions on GO properties was studied by comparing two systems: a solid sample and a liquid dispersion, which were analyzed during the course of 3 years. For this purpose, stability, O/C ratio and optical band‐gap of the stored samples were analyzed through time by means of zeta potential, X‐ray photoelectron spectroscopy (XPS) and UV‐Vis. Results show the difference in stability between the samples due to oxygen loss in the GO structure, confirmed by XPS. Moreover, optical band‐gap shows that the solid sample decreases its value around 64% compared to the liquid dispersion. X-ray photoelectron spectroscopy ; Graphene ; Dispersion (optics) ; Oxide ; Materials science ; Band gap ; Supercapacitor ; Nanomaterials ; Chemical stability ; Conductivity ; Zeta potential ; Chemical engineering ; Nanotechnology ; Electrochemistry ; Electrode ; Chemistry ; Optoelectronics ; Nanoparticle ; Optics ; Physical chemistry Graphene research and applications ; Graphene and Nanomaterials Applications ; Supercapacitor Materials and Fabrication
Authors: Saffron J. Bryant | Vincenzo Calabrese | Marcelo Alves da Silva | Kazi M. Zakir Hossain | Janet L. Scott | Karen J. Edler
Source: PLoS ONE (article, 2021-07-07)
Field: Materials Science — Biomaterials

Rheological modification of partially oxidised cellulose nanofibril gels with inorganic clays This study aimed to quantify the influence of clays and partially oxidised cellulose nanofibrils (OCNF) on gelation as well as characterise their physical and chemical interactions. Mixtures of Laponite and montmorillonite clays with OCNF form shear-thinning gels that are more viscous across the entire shear range than OCNF on its own. Viscosity and other rheological properties can be fine-tuned using different types of clay at different concentrations (0.5-2 wt%). Laponite particles are an order of magnitude smaller than those of montmorillonite (radii of 150 Å compared to 2000 Å) and are therefore able to facilitate networking of the cellulose fibrils, resulting in stronger effects on rheological properties including greater viscosity. This work presents a mechanism for modifying rheological properties using renewable and environmentally-friendly nanocellulose and clays which could be used in a variety of industrial products including home and personal care formulations. Cellulose ; Rheology ; Chemistry ; Chemical engineering ; Surface modification ; Materials science ; Organic chemistry ; Composite material ; Engineering ; Physical chemistry Advanced Cellulose Research Studies ; Polysaccharides and Plant Cell Walls ; Polysaccharides Composition and Applications
Authors: Flavia Artizzu | Davide Espa | Luciano Marchiò | Luca Pilia | Angela Serpe | Paola Deplano
Source: Inorganica Chimica Acta (article, 2021-12-02)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Progress and perspectives on strategies to control photochemical properties in Metallo-Dithiolene Donor-Acceptor systems Hyperpolarizability ; Chemistry ; Acceptor ; Chemical physics ; Molecule ; Photochemistry ; Ion ; Topology (electrical circuits) ; Nanotechnology ; Materials science ; Organic chemistry ; Polarizability Nonlinear Optical Materials Research ; Organic and Molecular Conductors Research ; Perovskite Materials and Applications
Authors: Tatiana N. Tikhonova | Nataliya N. Rovnyagina | Zohar A. Arnon | Boris P. Yakimov | Yuri M. Efremov | Dana Cohen‐Gerassi | Michal Halperin‐Sternfeld | Nastasia V. Kosheleva | Vladimir P. Drachev | Andrey А. Svistunov | Peter Timashev | Lihi Adler‐Abramovich | Evgeny A. Shirshin
Source: Angewandte Chemie (article, 2021-09-30)
Field: Materials Science — Biomaterials

Mechanical Enhancement and Kinetics Regulation of Fmoc‐Diphenylalanine Hydrogels by Thioflavin T Abstract The self‐assembly of peptides is a key direction for fabrication of advanced materials. Novel approaches for fine tuning of macroscopic and microscopic properties of peptide self‐assemblies are of a high demand for constructing biomaterials with desired properties. In this work, while studying the kinetics of the Fmoc‐Diphenylalanine (Fmoc‐FF) dipeptide self‐assembly using the Thioflavin T (ThT) dye, we observed that the presence of ThT strongly modifies structural and mechanical properties of the Fmoc‐FF hydrogel. Notably, the presence of ThT resulted in a tenfold increase of the gelation time and in the formation of short and dense fibers in the hydrogel. As a result of these morphological alteration higher thermal stability, and most important, tenfold increase of the hydrogel rigidity was achieved. Hence, ThT not only slowed the kinetics of the Fmoc‐FF hydrogel formation, but also strongly enhanced its mechanical properties. In this study, we provide a detailed description of the ThT effect on the hydrogel properties and suggest the mechanisms for this phenomenon, paving the way for the novel approach to the control of the peptide hydrogels’ micro‐ and macroscale properties. Self-healing hydrogels ; Kinetics ; Dipeptide ; Thioflavin ; Chemistry ; Peptide ; Self-assembly ; Thermal stability ; Structural rigidity ; Nanotechnology ; Fabrication ; Chemical engineering ; Biophysics ; Materials science ; Polymer chemistry ; Organic chemistry ; Biochemistry Supramolecular Self-Assembly in Materials ; Polydiacetylene-based materials and applications ; Hydrogels: synthesis, properties, applications
Authors: Xinzhang Lin | Xuemei Fu | Yang Yang | Xiuqing Ren | Jie Tang | Chao Liu | Jiahui Huang
Source: Inorganic Chemistry (article, 2021-07-08)
Field: Materials Science — Materials Chemistry

Synthesis and Optical Properties of Unique Pt<sub>1</sub>Ag<sub>24</sub> Nanoclusters with Mixed Exterior Motif Structures The atomic arrangement of metal nanoclusters plays a significant role in the structure-property correlation. Herein, we present a novel Pt<sub>1</sub>Ag<sub>24</sub>(SR)<sub>16</sub>(PPh<sub>3</sub>)<sub>3</sub> nanocluster with a unique structure, different from two reported Pt<sub>1</sub>Ag<sub>24</sub> nanoclusters. The nanocluster was prepared via one-pot synthesis and solvent extraction. It has a centered icosahedral Pt<sub>1</sub>Ag<sub>12</sub> kernel and an open shell composed of three Ag<sub>2</sub>(SR)<sub>3</sub>(PPh<sub>3</sub>) staple motifs and a unique trefoil-like Ag<sub>6</sub>(SR)<sub>7</sub> motif. The three kinds of Pt<sub>1</sub>Ag<sub>24</sub> nanoclusters have the same kernel but different shell configurations. The fine-tuning of structures is necessary and significant for the investigation of the relationship of structures and properties. The different UV-vis absorption spectra indicate that the optical properties of three Pt<sub>1</sub>Ag<sub>24</sub> nanoclusters mainly depend on the exterior shell configuration and the metal-ligand interface. This work provides insights toward growth mechanism and the structure-property correlation of metal nanoclusters. Nanoclusters ; Chemistry ; Icosahedral symmetry ; Metal ; Crystallography ; Nanotechnology ; Chemical physics ; Materials science ; Organic chemistry Nanocluster Synthesis and Applications ; Random Matrices and Applications ; Gold and Silver Nanoparticles Synthesis and Applications
Authors: Milena Simić | Miloš Petković | Predrag Jovanović | Miloš Jovanović | Gordana Tasić | Irina Besu | Željko Žižak | Ivana Aleksić | Jasmina Nikodinović‐Runić | Vladimir Savić
Source: Archiv der Pharmazie (article, 2021-08-10)
Field: Chemistry — Organic Chemistry

Fragment‐type 4‐azolylcoumarin derivatives with anticancer properties Abstract Several coumarin derivatives with a directly attached azole substituent at C‐4 were synthesized and biologically studied for their anticancer properties. The cell lines used for this investigation (HeLa, K‐562, MDA‐MB‐53, and MCF‐7) demonstrated different sensitivities. The best response in the MTT (3‐(4,5‐dimethyl‐2‐thiazolyl)‐2,5‐diphenyl‐2 H ‐tetrazolium bromide) assay was shown by K‐562 cells, with compounds displaying activity ( 3c , IC 50 3.06 μM; 4a , IC 50 5.24 μM; 4c , IC 50 4.7 μM) similar to that of cisplatin (IC 50 ~6 μM), which was used as the standard. The studied azole‐substituted coumarins demonstrated weaker activity toward other cell lines, except for compound 4c , which was equally potent in the case of MCF‐7 cells. Additional biological evaluations supported interference with the cell cycle as a potential mechanism of action and confirmed the absence of toxicity in zebrafish embryos. On the basis of these initial results, 4‐azole coumarins should be explored further. Although their activity would need additional optimization, the fact that these compounds are fragment‐like structures with MW &lt;300 and clog P &lt;3 offers enough flexibility to fine‐tune their drug‐like properties. HeLa ; Chemistry ; Azole ; Coumarin ; Stereochemistry ; Substituent ; Cell culture ; Biological activity ; Combinatorial chemistry ; In vitro ; Biochemistry ; Organic chemistry Synthesis and biological activity ; Plant chemical constituents analysis ; Click Chemistry and Applications
Authors: Huizhi Bao | Alain Y. Li | Vanessa Kairouz | Audrey Moores
Source: Canadian Journal of Chemistry (article, 2021-10-25)
Field: Chemistry — Organic Chemistry

Ultra-fast Cu-based A<sup>3</sup>-coupling catalysts: faceted Cu<sub>2</sub>O microcrystals as efficient catalyst-delivery systems in batch and flow conditions Cu(I) catalysts were studied for the synthesis of a propargylamine via A 3 -coupling of aldehyde, amine, and alkyne, under solvent-free and low loading conditions, using batch microwave or flow thermal heating. We explored ultra-low loading conditions with Cu(I) salts as fast and active catalysts featuring turnover frequencies (TOFs) above 10 5 h −1 . Well-defined octahedral and cubic Cu 2 O microcrystals were also successfully applied and compared with this reaction. Both types of microcrystals exhibited excellent catalytic activities within minutes, via in situ generation of low dose of Cu(I) ions within the reaction medium, to achieve TON beyond 2000 and recycling up to 10 times in a flow reactor. The study of the catalytic system demonstrated that the activity was surface-structure dependent and allowed for the design of low Cu contamination A 3 -coupling systems, affording a product at the decigram scale, with Cu contamination below FDA recommendations for drug synthesis, without the need for a purification procedure. Catalysis ; Chemistry ; Amine gas treating ; Alkyne ; Copper ; Aldehyde ; Flow chemistry ; Solvent ; Ion ; Coupling reaction ; Chemical engineering ; Nuclear chemistry ; Organic chemistry Catalytic Cross-Coupling Reactions ; Catalytic Alkyne Reactions ; Nanomaterials for catalytic reactions