jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: OilGas ScientificResearch Project" | F.F. Valiyev
Source: Azerbaijan Chemical Journal (article, 2020-06-18)
Field: Materials Science — Electronic, Optical and Magnetic Materials

SYNTHESIS, CRYSTAL STRUCTURE, SPECTRAL AND MAGNETIC PROPERTIES OF MONONUCLEAR COPPER(II) COMPLEX WITH PYRAZINE-MODULATED 2,2'-DIPYRIDYLAMINE New copper(II) complex [Cu(Hppza)(CH 3 COO) 2 ]2H 2 O was synthesized via the interaction of Cu(CH 3 COO) 2 H 2 O with the unsymmetrical pyrazine-modulated dipyridylamine ligand -Hppza. The crystal structure, spectral and magne-tic properties of this complex are determined. It was found that the coordination polyhedron of the copper(II) ion in this complex is an elongated octahedron, in the equatorial plane of which there are two nitrogen atoms from Hppza ligand and two oxygen atoms from two carboxylate anions. The formation of intermolecular hydrogen bonds has been observed. Pyrazine ; Chemistry ; Crystallography ; Copper ; Carboxylate ; Crystal structure ; Ligand (biochemistry) ; Octahedron ; Hydrogen bond ; Intermolecular force ; Ion ; Stereochemistry ; Molecule ; Organic chemistry Magnetism in coordination complexes ; Metal complexes synthesis and properties ; Lanthanide and Transition Metal Complexes
Authors: Long Yang
Source: MPG.PuRe (Max Planck Society) (article, 2020-01-01)
Field: Materials Science — General Materials Science

Design of smart responsive polymers and polymer nanoparticles 148 Seiten Polymer ; Nanoparticle ; Smart polymer ; Nanotechnology ; Materials science ; Polymer science ; Composite material Material Properties and Applications ; biodegradable polymer synthesis and properties
Authors: Xavi Ribas | R. Xifra | Xavier Fontrodona
Source: Molecules (article, 2020-10-09)
Field: Chemistry — Organic Chemistry

Bis-Phenoxo-CuII2 Complexes: Formal Aromatic Hydroxylation via Aryl-CuIII Intermediate Species Ullmann-type copper-mediated arylC-O bond formation has attracted the attention of the catalysis and organometallic communities, although the mechanism of these copper-catalyzed coupling reactions remains a subject of debate. We have designed well-defined triazamacrocyclic-based aryl-Cu<sup>III</sup> complexes as an ideal platform to study the C-heteroatom reductive elimination step with all kinds of nucleophiles, and in this work we focus our efforts on the straightforward synthesis of phenols by using H<sub>2</sub>O as nucleophile. Seven well-defined aryl-Cu<sup>III</sup> complexes featuring different ring size and different electronic properties have been reacted with water in basic conditions to produce final bis-phenoxo-Cu<sup>II</sup><sub>2</sub> complexes, all of which are characterized by XRD. Mechanistic investigations indicate that the reaction takes place by an initial deprotonation of the NH group coordinated to Cu<sup>III</sup> center, subsequent reductive elimination with H<sub>2</sub>O as nucleophile to form phenoxo products, and finally air oxidation of the Cu<sup>I</sup> produced to form the final bis-phenoxo-Cu<sup>II</sup><sub>2</sub> complexes, whose enhanced stability acts as a thermodynamic sink and pushes the reaction forward. Furthermore, the corresponding triazamacrocyclic-Cu<sup>I</sup> complexes react with O<sub>2</sub> to undergo 1e<sup>-</sup> oxidation to Cu<sup>II</sup> and subsequent C-H activation to form aryl-Cu<sup>III</sup> species, which follow the same fate towards bis-phenoxo-Cu<sup>II</sup><sub>2</sub> complexes. This work further highlights the ability of the triazamacrocyclic-Cu<sup>III</sup> platform to undergo aryl-OH formation by reductive elimination with basic water, and also shows the facile formation of rare bis-phenoxo-Cu<sup>II</sup><sub>2</sub> complexes. Chemistry ; Deprotonation ; Reductive elimination ; Nucleophile ; Aryl ; Medicinal chemistry ; Catalysis ; Combinatorial chemistry ; Organic chemistry Catalytic C–H Functionalization Methods ; Catalytic Cross-Coupling Reactions ; Cyclopropane Reaction Mechanisms
Authors: Cathrin Kronenbitter | Hironobu Watanabe | Sadahito Aoshima | Helmut Cölfen
Source: Materials Advances (article, 2020-01-01)
Field: Chemistry — Organic Chemistry

Temperature-induced switchable magnetite nanoparticle superstructures In this study we describe the green synthesis of temperature-switchable polymer-magnetite nanoparticles (PMNPs) in water at room temperature <italic>via</italic> an improved co-precipitation pathway for reversible switchable superstructures. Magnetite ; Magnetite Nanoparticles ; Nanoparticle ; Materials science ; Precipitation ; Nanotechnology ; Chemical engineering ; Polymer ; Magnetic nanoparticles ; Composite material ; Metallurgy Nanomaterials for catalytic reactions ; Nanoparticle-Based Drug Delivery ; Iron oxide chemistry and applications
Authors: Ashley Lamb
Source: Digital Scholarship - UNLV (University of Nevada Reno) (article, 2020-11-17)
Field: Materials Science — Biomaterials

3-D Silk Fibroin Porous Particles Created by the Ouzo Effect for Biomedical Applications Due to its high biocompatibility and biodegradability, silk fibroin  produced from Bombyx mori (B. mori) cocoons  has been at the forefront of research for many biomedical application formats: hydrogels, films, microspheres, and porous sponges/scaffolding, to name a few. For drug delivery, in particular, porous particles are desirable for their large surface area, uniform and tunable pore structure, and high porosity. This thesis focuses on the fabrication of porous particles from silk fibroin by the very interesting Ouzo effect. The Ouzo effect, so named because of the Greek beverage ouzo, describes the phenomenon of an ethanol + anethole oil solution turning milky-white in color once water is added in due to the spontaneous nucleation of oil droplets. Using the Ouzo effect to fabricate porous particles solves the numerous issues of typical colloidal droplet formation by not requiring energy nor a surfactant, which is cost effective and environmentally friendly; the Ouzo effect also tackles the so-called coffee ring effect of previous particle fabrication, in which a solutions suspension medium travels to the edge of a droplet and leaves a residual ring. An Ouzo droplet is able to self-lubricate at the droplets edge and form an oil ring that forces the suspension medium to form a 3-D particle with tunable pore shape. By using the Ouzo effect to fabricate these particles from silk fibroin, the result is consistent macro-porous (pore diameter being greater than 50 nm) structures with relative 2-D porosity values greater than 70%. These features make the particles ideal for drug loading and delivery. Fibroin ; SILK ; Porosity ; Polymer science ; Materials science ; Composite material Silk-based biomaterials and applications ; Dyeing and Modifying Textile Fibers ; Electrospun Nanofibers in Biomedical Applications
Authors: Rafael T. P. da Silva | Marcos V. Petri | Estela Ynés Valencia Morante | Pedro H. C. Camargo | Susana I. Córdoba de Torresi | Beny Spira
Source: bioRxiv (Cold Spring Harbor Laboratory) (preprint, 2020-01-12)
Field: Materials Science — Materials Chemistry

Visible Light Plasmon Excitation of Silver Nanoparticles Against Antibiotic-Resistant <i>Pseudomonas aeruginosa</i> ABSTRACT The interaction of metallic nanoparticles with light excites a local surface plasmon resonance (LSPR). This phenomenon enables the transfer of hot electrons to substrates that release Reactive Oxygen Species (ROS). In this context, the present study was aimed at enhancing the antibacterial effect of citrate-covered silver nanoparticles (AgNPs), which already possess excellent antimicrobial properties, via LSPR excitation with visible LED against Pseudomonas aeruginosa , one of the most refractory organisms to antibiotic treatment. The Minimum Inhibitory Concentration (MIC) of AgNPs was 10 μg/ml under dark conditions and 5 μg/ml under light conditions. The combination of light and AgNPs led to 100% cell death after 60 minutes. Quantification of ROS via flow cytometry showed that LSPR stimulated AgNPs increased intracellular ROS concentration by 4.8-fold, suggesting that light-exposed AgNPs caused cell death via ROS production. Light exposition caused a small release of silver ions (0.4%) reaching a maximum after 6 hours. This indicates that silver ions play at most a secondary role in P. aeruginosa death. Overall, the results presented here show that LSPR generation from AgNPs by visible light enhances the antimicrobial activity of silver nanoparticles and can be an alternative for the treatment of topic infections caused by antibiotic-resistant bacteria such as P. aeruginosa . Surface plasmon resonance ; Silver nanoparticle ; Pseudomonas aeruginosa ; Antimicrobial ; Reactive oxygen species ; Chemistry ; Nanoparticle ; Context (archaeology) ; Minimum inhibitory concentration ; Biophysics ; Nanotechnology ; Materials science ; Bacteria ; Biochemistry ; Biology ; Organic chemistry Nanoparticles: synthesis and applications ; Biosensors and Analytical Detection ; Gold and Silver Nanoparticles Synthesis and Applications
Authors: Shuyang Zhang | Maren Pink | Tobias Junghoefer | Wenchao Zhao | Sheng‐Ning Hsu | Suchada Rajca | Bryan W. Boudouris | Maria Benedetta Casu | Andrzej Rajca
Source: ChemRxiv (preprint, 2020-10-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Conducting High-Spin (S = 1) Organic Diradical with Robust Stability Triplet ground-state organic molecules are of interest with respect to several emerging technologies but usually show limited stability, especially, as thin films. We report an organic diradical, based entirely on two Blatter radicals, that possesses triplet ground state (2J/k ≈ 220 K, EST ≈ 0.4 kcal mol-1 ) and robust stability, with onset of decomposition above 264 C (TGA). Polycrystalline diradical is a good electrical conductor with conductivity comparable to the out-of-plane conductivity in highly oriented pyrolytic graphite (HOPG). The diradical is evaporated under ultra-high vacuum to form thin films, which are stable on air for at least 18 and 48 h, as demonstrated by X-ray photoelectron and electron paramagnetic resonance (EPR) spectroscopies, respectively. Diradical ; Electron paramagnetic resonance ; Pyrolytic carbon ; Ground state ; Spin (aerodynamics) ; Paramagnetism ; Chemistry ; Conductivity ; Materials science ; Condensed matter physics ; Physical chemistry ; Nuclear magnetic resonance ; Organic chemistry ; Physics ; Atomic physics ; Pyrolysis ; Excited state ; Singlet state ; Thermodynamics Organic and Molecular Conductors Research ; Molecular Junctions and Nanostructures ; Synthesis and Properties of Aromatic Compounds
Authors: Johanna Engelke | Bryan T. Tuten | Ralf Schweins | Hartmut Komber | Leonie Barner | Laura Plüschke | Christopher Barner‐Kowollik | Albena Lederer
Source: ChemRxiv (preprint, 2020-08-24)
Field: Chemistry — Organic Chemistry

An In-Depth Analysis Approach Enabling Precision Single Chain Nanoparticle Design The formation of single chain nanoparticles (SCNPs) is typically characterized by a shift towards higher elution volumes in SEC due to size decrease upon folding. However, a step-change in SCNP analysis is required for understanding of the nature of intramolecular SCNP folding. Herein, we exploit a unique combination of SANS, 19F NMR spectroscopy, and multidetection SEC to generate a systematic view of the folded morphology of poly(butyl acrylate) based-SCNPs as a function of their reactive group density and molar mass. In addition to detailed morphological insights, we establish that the primary factor dictating the compaction of SCNPs is their reactive group density, which is ineffective below 5 mol%, reaching maximum compaction close to 30 mol%. Above 20 kDa the molar mass of the precursor polymers has a minor impact on how an SCNP compacts. Molar mass ; Intramolecular force ; Nanoparticle ; Folding (DSP implementation) ; Compaction ; Polymer ; Chemistry ; Acrylate ; Molar ratio ; Chemical engineering ; Nanotechnology ; Polymer chemistry ; Materials science ; Monomer ; Stereochemistry ; Organic chemistry ; Composite material ; Catalysis Advanced Polymer Synthesis and Characterization ; Polymer Surface Interaction Studies ; Polymer Nanocomposites and Properties
Authors: Carmen Leitner | S Tao | S Zhu | T Feng | C Zheng | B Yang | J Ochi | K Tanaka | Y Chujo | S Suzuki | S Sasaki | A Sairi | R Iwai | B Tang | G Konishi | X Cai | B Liu | Z Zhao | H Zhang | J Lam | A Suleymanov | M Doll | A Ruggi | R Scopelliti | F Fadaei-Tirani | K Severin | L Shi | Y.-H Liu | K Li | A Sharma | K.-K Yu | L.-L Ji | Q Li | H Zhou | J Zhang | Kim | X.-Q Yu | Y Su | Y Zhang | Z Wang | W Gao | P Jia | D Zhang | C Yang | Y Li | Y Zhao | S Zheng | T Zhu | Y Wang | T Yang | W Yuan | B Chen | W Huang | H Su | H Miao | X Zhang | G Zhang | J Li | P Wu | W Jiang | B Li | B Wang | H Zhu | H Roesky | J Wang | Y Fang | C Li | L Niu | W Fang | G Cui | Q Yang | E Hamzehpoor | D Perepichka ; Biosensors | H Peng | Z Huang | H Deng | W Wu | K Huang | Z Li | W Chen | * Liu | L Jiang | H Ding | S Lu | * Geng | G Xiao | * Zou | H Bi | ; Huang | Z Bin | * Su | F Yang | J Lan | J You | ; Biesen | N Nirmalananthan-Budau | K Hoffmann | U Resch-Genger | T Mller | Y Huang
Source: Angewandte Chemie International Edition (article, 2020-06-05)
Field: Chemistry — Organic Chemistry

Graphical Abstract: Angew. Chem. Int. Ed. 25/2020 In their Communication on page 9908, H. Tang, D Citation ; INT ; Computer science ; Library science ; Information retrieval ; Programming language Click Chemistry and Applications ; Radical Photochemical Reactions ; Catalytic C–H Functionalization Methods
Authors: Chenliang Shi | Yukun Yang | Ling Lin | Wenjia Luo | Maoqing Deng | Pingya Luo | Yujie Wu
Source: Preprints.org (preprint, 2020-03-04)
Field: Materials Science — Materials Chemistry

Synthesis of Aminated Polystyrene and Its Self-assembly with Nanoparticles at Oil/water Interface Nanoparticle (NP)&amp;ndash;surfactants formed by the self-assembly of NPs and end-functionalized polymers at the hydrophilic/hydrophobic interface have a wide range of applications in many fields. In this study, the influence of density of amino groups, NPs dimension and pH on the interaction between end-functionalized polymers and NPs were extensively investigated. Single amino-terminated polystyrene (PS-NH2, Mw &amp;asymp; 0.6k, 2.5k, 3.5k, 3.9k) and diamino-terminated polystyrene (H2N-PS-NH2, Mw &amp;asymp; 1.1k, 2.8k) were prepared using reversible addition&amp;ndash;fragmentation chain transfer polymerization and atom transfer radical polymerization. NPs with different dimensions (zero-dimensional carbon dots with sulfonate groups, one-dimensional cellulose nanocrystals with sulfate groups and two-dimensional graphene with sulfonate groups) in the aqueous phase were added into the toluene phase containing the aminated PS. The influence of pH and the molecular weight of amino-terminated PS on the interfacial tension between two phases were investigated. The results indicate that aminated PS exhibited the strongest interfacial activity after compounding with sulfonated NPs at a pH of 3. Terminating PS with amino groups on both ends leads to better performance in in reducing the water/toluene interfacial tension than modifying the molecular structure of PS on a single end. The dimension of sulfonated NPs also contributed significantly to the reduction of the water/toluene interfacial tension. The minimal interfacial tension was 4.49 mN/m after compounding PS-NH2 with sulfonated zero-dimensional carbon dots. Molecular dynamics simulation on the evolution of the water/toluene interface in the presence of sulfonated carbon dots and H2N-PS-NH2 revealed that these opposite charged substances moved towards the interface in an extreme short time and orderly assembled in a thermodynamic equilibrium. Polystyrene sulfonate ; Polystyrene ; Surface tension ; Polymer chemistry ; Atom-transfer radical-polymerization ; Polymer ; Aqueous solution ; Chemical engineering ; Toluene ; Sulfonate ; Aqueous two-phase system ; Interfacial polymerization ; Polymerization ; Materials science ; Chemistry ; Organic chemistry ; Monomer ; PEDOT:PSS Pickering emulsions and particle stabilization ; Electrohydrodynamics and Fluid Dynamics ; Surfactants and Colloidal Systems
Authors: José María Andrés Castán
Source: SPIRE - Sciences Po Institutional REpository (preprint, 2020-10-02)
Field: Materials Science — Polymers and Plastics

Push-pull-based materials for organic photovoltaics The continuous efforts devoted to improving the performances in organic photovoltaics (OPV) have enhanced the photoconversion efficiencies over 18% so far. However, a critical vision of the state-of-the-art publications highlights that thehighest efficiencies are generally paired with an enhancement of the synthetic complexity of both the materials (donor and acceptor) and the fabrication procedure. That is the reason why the preparation of simpler and less expensive materials is that crucial. In this regard, after a first chapter reviewing the recent progress in OPV, a second chapter is focused on the synthesis of D-π-A molecules based on the N-methyl-N-phenylthiophen-2-amine (MPTA) electron-donor unit, which was not previously used in the field. A series of derivatives is synthesized by modulating the π-spacer and the electron-withdrawing group A and theimpact on their optical, electrochemical and photovoltaic properties is naturally investigated. A third chapter is related to the structural modification of a recently reported push-pull molecule, namely TPA-T-DCV-Ph. Its additional phenyl ring in the accepting moiety led to a higher exciton diffusion length and therefore photoconversion efficiency in comparison to the well-known TPA-T-DCV. Hence, two different structural modifications of this donor are reported. Eventually, a fourth chapter is related to the functionalization of a promising and unexplored rylene, namely the benzothioxanthene (BTXI) whose most attractive features are its low synthetic cost and outstanding optical and electrochemical properties. Thus, its reactivity is explored in a deeper level and the properties of the new derivatives are studied. Photovoltaics ; Organic solar cell ; Materials science ; Nanotechnology ; Engineering ; Engineering physics ; Photovoltaic system ; Electrical engineering Conducting polymers and applications
Authors: Omer Kirshenboim | Alexander Frenklah | Sebastian Kozuch
Source: ChemRxiv (preprint, 2020-11-16)
Field: Chemistry — Physical and Theoretical Chemistry

Switch Chemistry at Cryogenic Conditions: Quantum Tunnelling under Electric Fields While the influence of intramolecular electric fields is a known feature in enzymes, the use of oriented external electric fields (EEF) to enhance or inhibit molecular reactivity is a promising topic still in its infancy. Herein we will explore computationally the effects that EEF can provoke in simple molecules close to the absolute zero, where quantum tunnelling (QT) is the sole mechanistic option. We studied three exemplary systems, each one with different reactivity features and known QT kinetics:  bond-shifting in pentalene, Cope rearrangement in semibullvalene, and cycloreversion of diazabicyclohexadiene. The kinetics of these cases depdend both on the field strength and its direction, usually giving subtle but remarkable changes. However, for the cycloreversion, which suffers large changes on the dipole through the reaction, we also observed striking results. Between the effects caused by the EEF on the QT we observed an inversion of the Arrhenius equation, deactivation of the molecular fluxionality, and stabilization or instantaneous decomposition of the system. All these effects may well be achieved, literally, at the flick of a switch. Quantum tunnelling ; Electric field ; Intramolecular force ; Chemistry ; Reactivity (psychology) ; Dipole ; Pentalene ; Arrhenius equation ; Quantum ; Kinetics ; Molecule ; Chemical physics ; Computational chemistry ; Physics ; Stereochemistry ; Condensed matter physics ; Quantum mechanics ; Organic chemistry Chemical Reactions and Mechanisms ; Molecular Junctions and Nanostructures ; Advanced Chemical Physics Studies
Authors: Alexey Eremin | Hajnalka Nádasi | Ralf Stannarius
Source: Physical Sciences Reviews (article, 2020-12-03)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Multifunctionality by dispersion of magnetic nanoparticles in anisotropic matrices Abstract Interactions between magnetic nanoparticles and an anisotropic environment give rise to a variety of new magneto-optical, rheological and mechanical phenomena. This opens new avenues for developing novel multifunctional materials. In the course of this project, we investigated three types of anisotropic systems: dispersions of shape-anisotropic nanocrystals, magnetically doped molecular and colloidal liquid crystals, and organoferrogels. They were investigated by means of magneto-optical observations and by a magneto-mechanical torsion pendulum method. Anisotropy ; Materials science ; Magnetic nanoparticles ; Nanoparticle ; Colloid ; Torsion pendulum clock ; Nanocrystal ; Rheology ; Magnetic anisotropy ; Optical anisotropy ; Nanotechnology ; Dispersion (optics) ; Nanofluid ; Condensed matter physics ; Liquid crystal ; Chemical physics ; Magnetic field ; Composite material ; Magnetization ; Chemistry ; Optics ; Physics ; Optoelectronics ; Physical chemistry Liquid Crystal Research Advancements ; Surfactants and Colloidal Systems ; Characterization and Applications of Magnetic Nanoparticles
Authors: Irdi Murataj | Marwan Channab | Eleonora Cara | Candido Fabrizio Pirri | Luca Boarino | Angelo Angelini | Federico Ferrarese Lupi
Source: Research Square (preprint, 2020-11-05)
Field: Materials Science — Materials Chemistry

Hyperbolic Metamaterials via Hierarchical Block Copolymer Nanostructures Copolymer ; Metamaterial ; Nanostructure ; Block (permutation group theory) ; Materials science ; Nanotechnology ; Topology (electrical circuits) ; Mathematics ; Geometry ; Composite material ; Optoelectronics ; Polymer ; Combinatorics Block Copolymer Self-Assembly ; Fluid Dynamics Simulations and Interactions ; Advanced Polymer Synthesis and Characterization
Authors: Man Pan Leung | Chung Chiu Yeung | Pui Ying Choy | Chau Ming So | Fuk Yee Kwong
Source: Chinese Journal of Organic Chemistry (article, 2020-01-01)
Field: Chemistry — Organic Chemistry

Facile One-Pot Assembly of New 5-Substituted P,O-Type Indolylphosphine Ligands for Palladium-Catalyzed Suzuki-Miyaura Cross-Coupling of Aryl Chlorides 从容易获得且便宜的原材料出发，通过简单的一锅式组装方法合成了一种新的P，O-型吲哚基膦配体，并将其用于钯催化的芳基氯Suzuki-Miyaura交叉偶联反应，结果显示配体上的“取代基”能促进该反应的活性，其钯催化剂载量可降至0.01 mol%. Chemistry ; Aryl ; Palladium ; Catalysis ; Combinatorial chemistry ; Suzuki reaction ; Coupling (piping) ; Coupling reaction ; Organic chemistry ; Medicinal chemistry ; Polymer chemistry ; Metallurgy Catalytic Cross-Coupling Reactions ; Chemical synthesis and alkaloids ; Synthesis of Indole Derivatives