jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Phil Szuromi
Source: Science (article, 2021-08-26)
Field: Materials Science — Materials Chemistry

Visibly controlling bond breaking Photoactivated Bonds Photodynamic bonds that are stable under dark conditions but break when photoexcited enable an array of materials applications where switching is desired. For cycloadditions and reversions of conjugated organic molecules or radical formation, the excitation energy to activate bonds usually requires ultraviolet light. Han et al. report that the coordination of a selenoether ligand with a ruthenium coordination complex can be reversed by breaking the ruthenium–selenium bond with visible light and can also be restored after dark storage. They applied this approach to photocontrol of amphiphiles between spherical micelles and bowl shapes, wetting of surfaces, and polymer gelling. J. Am. Chem. Soc. 10.1021/jacs.1c05648 (2021). Ruthenium ; Photochemistry ; Chemistry ; Conjugated system ; Molecule ; Polymer ; Ligand (biochemistry) ; Catalysis ; Organic chemistry Photochromic and Fluorescence Chemistry ; Radical Photochemical Reactions ; Click Chemistry and Applications
Authors: Candyce R. Clark | Eric C. Hosten | Richard Betz
Source: Zeitschrift für Kristallographie - New Crystal Structures (article, 2021-02-14)
Field: Chemistry — Inorganic Chemistry

The crystal structure of 5-carboxy-2-(hydroxymethyl)-1<i>H</i>-imidazol-3-ium-4-carboxylate, C<sub>6</sub>H<sub>8</sub>N<sub>2</sub>O<sub>6</sub> Abstract C 6 H 8 N 2 O 6 , monoclinic, P 2 1 / c (no. 14), a = 7.4709(4) Å, b = 14.2051(9) Å, c = 7.3198(4) Å, <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <m:mrow> <m:mi>β</m:mi> </m:mrow> </m:math> $\beta $ = 97.096(4)°, V = 770.86(8) Å 3 , Z = 4, R gt ( F ) = 0.0346, wR ref ( F 2 ) = 0.0946, T = 200 K. Monoclinic crystal system ; Hydroxymethyl ; Scroll ; Carboxylate ; Stereochemistry ; Chemistry ; Mathematics ; Crystallography ; Crystal structure ; Engineering Crystal structures of chemical compounds ; Metal-Organic Frameworks: Synthesis and Applications ; Synthesis and biological activity
Authors: Ilya M. Sosnin
Source: Reviews on advanced materials and technologies (article, 2021-01-01)
Field: Materials Science — Materials Chemistry

Structural-Dependent Photocatalytic Properties of Zinc Oxide The present paper describes the effect of the structure of zinc oxide on its optical, electrical and photocatalytic properties. Examples of the influence of defects and lattice symmetry on photocatalytic activity are given. It is shown that oxygen vacancies allow to increase the rate of photocatalytic reaction due to donor properties and faceting allows to change the photocatalytic activity due to anisotropy of electric conductivity of zinc oxide. The mechanism of the influence of the dislocations and complex defects on zinc oxide photocatalytic properties is proposed. The present data can be used for development of photocatalysts based on zinc oxide, and for describing the photocatalytic properties of other semiconductors. Photocatalysis ; Zinc ; Materials science ; Faceting ; Oxide ; Semiconductor ; Anisotropy ; Chemical engineering ; Inorganic chemistry ; Chemistry ; Optoelectronics ; Metallurgy ; Optics ; Catalysis ; Crystallography ; Physics ZnO doping and properties ; Copper-based nanomaterials and applications ; Gas Sensing Nanomaterials and Sensors
Authors: Zhoulong Fan | Xiangyang Chen | Keita Tanaka | Han Seul Park | Nelson Y. S. Lam | Jonathan J. Wong | K. N. Houk | Jin‐Quan Yu
Source: ChemRxiv (preprint, 2021-10-11)
Field: Chemistry — Organic Chemistry

Unified Template Strategy for Editing Multiple Remote C–H Bonds Through consecutive selective C–H functionalization at multiple sites, the direct molecular editing of heteroarene carbon-hydrogen (C–H) bonds has the potential to grant rapid access into diverse molecular space; a valuable but often challenging venture to achieve in medicinal chemistry. Contrasting with electronically-biased heterocyclic C–H bonds, remote benzocyclic C–H bonds on bicyclic aza-arenes are especially difficult to differentiate due to lack of intrinsic steric/electronic biases. Through careful consideration of distance and geometric parameters, we herein report a unified catalytic directing template strategy that enables the modular functionalization of chemically-similar and adjacent remote positions on bicyclic aza-arene scaffolds. Differentiated by using two structurally distinct catalytic directing templates, this method enables direct C–H olefination, alkynylation, and allylation at previously inaccessible C6 and C7 positions of quinolines, and is amenable to the iterative, modular, and late-stage C–H editing of quinoline-containing pharmacophores and pharmaceuticals. This report, in combination with our previous C5-selective template and other complementary methods, now fully establishes a unified ‘molecular editing’ strategy to directly modify aza-arene heterocycles at any given site. Pharmacophore ; Template ; Combinatorial chemistry ; Steric effects ; Bicyclic molecule ; Chemistry ; Quinoline ; Catalysis ; Modular design ; Computer science ; Surface modification ; Stereochemistry ; Organic chemistry Catalytic C–H Functionalization Methods ; Radical Photochemical Reactions ; Synthesis and Catalytic Reactions
Authors: Brody A. Frost
Source: cIRcle (University of British Columbia) (article, 2021-01-01)
Field: Materials Science — Biomaterials

Cellulose nanocrystals : from extraction to biomedical application With societal, industrial, and clinical progress continuously reaching greater heights, the crucial need for enhanced materials with versatile properties is ever increasing to help this growth. As such, polymer nanocomposites (PNCs) have been heavily researched, becoming redefined as their own class of materials, focusing on fundamental structure/property relationships, manufacturing techniques, and commercial applications, due to their remarkable properties and application versatility. Through countless nanoparticle and polymer matrix variations, PNCs can be finely-tuned to exhibit a multitude of unique characteristics. Utilizing this concept, the research laid out in the combined chapters of this dissertation sought to produce various PNCs embedded with cellulose nanocrystals/nanofibrils (CNCs/CNFs) and magnetic nanoparticles (MNPs) to obtain uniquely tunable properties to further progress the biomaterials field for biomedical applications. Initially, CNCs were extracted from the otherwise useless agricultural waste product of spent coffee grounds through phosphoric acid hydrolysis, and analyzed using multiple physical and chemical characterization techniques. In particular, a few crucial properties determined were aspect ratio of 12 ± 3, crystallinity of 74.2%, surface charge density of 48.4 ± 6.2 mmol/kg cellulose, and the ability to successfully reinforce PNCs, comparing well to other literature data and common commercial CNCs. Following extraction, CNCs/CNFs, as well as MNPs, were incorporated into various polymer matrices, including poly(ethylene glycol) diacrylate, sodium alginate, gelatin, and polyurethane, among others. Through solution casting and 3D bioprinting fabrication methods, as well as composition manipulation, CNCs/CNFs were able to reach ideal percolating networks within the PNCs for maximum mechanical reinforcement with minimal hindrance of the polymer matrix’s natural properties. The various PNC hydrogel scaffolds successfully demonstrated tunability of their nanostructural, mechanical, hydration, and biodegradation properties, utilizing the benefits of manipulated composition, crosslinking density, and nanofiller orientation to increase versatility for tissue engineering constructs. Additionally, MNP incorporation was shown to successfully produce inductive heating responses to promote topographical shape memory effects, while invoking minute thermal dissipation into surrounding environments to reduce thermal shock to seeded biological components. The success of this work makes strides to overcome a few crucial disadvantages of current PNC biomaterial hydrogels, specifically their inability to regenerate biomimetic native tissues during wound healing. Cellulose ; Extraction (chemistry) ; Nanotechnology ; Chemistry ; Computer science ; Materials science ; Polymer science ; Chromatography ; Biochemistry Advanced Cellulose Research Studies
Authors: Lei Li | Jinxing Song | Xin Yang | Shengpeng Wang | Zuguang Li | Yingying Chen | Aiyuan You
Source: Journal of Materials Science and Chemical Engineering (article, 2021-01-01)
Field: Chemistry — Organic Chemistry

Precise Synthesis of Acrylate Copolymer via RAFT Polymerization and Its Application A series of different sequence structure containing stearyl acrylate (SA) and hydroxyethyl acrylate (HEA) copolymer were synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization. The crystallization property of PHEA-b-PSA, PHEA-b-PSA-b-PHEA, PSA-b-PHEA-b-PSA, PHEA-co-PSA, and PHEA-grad-b-PSA were characterized by Differential Scanning Calorimetry (DSC). The condensed structure of different sequence copolymers were investigated using small-angle X-ray scattering (SAXS). A series of copolymers with different sequence structure were coated on the surface of polyester fabric, which can be found that PHEA-b-PSA-b-PHEA block copolymer has good water repellency. Copolymer ; Materials science ; Raft ; Polymer chemistry ; Chain transfer ; Acrylate ; Polymerization ; Small-angle X-ray scattering ; Radical polymerization ; Polymer ; Scattering ; Composite material ; Optics Advanced Polymer Synthesis and Characterization ; biodegradable polymer synthesis and properties ; Photopolymerization techniques and applications
Authors: A.B. Surovtsev | I.A. Mandzyuk | D.O. Chervakov | M.F. Seferova | О. В. Черваков
Source: Voprosy Khimii i Khimicheskoi Tekhnologii (article, 2021-10-01)
Field: Materials Science — Materials Chemistry

Study of the rheological properties of the highly-filled paste-like fuel composition based on oligomeric rubber and dispersed fillers We present the results of creation of paste-like fuel compositions with a high degree of filling (up to 90 wt.%) and investigation of their rheological properties. The developed composition contained the following components: a polymer matrix (type SNBR-N butadiene rubber) and a mixture of inorganic fillers (preliminarily surface-modified highly disperse potassium chloride, that was microencapsulated by using oligomeric products of polyehtyleneterepthalate glycerolize, and highly dispersed aluminum powder. A surface-active compound (oligomeric polioxypropylene glycol) and plasticizers of different natures were used as additional components, which were introduced in order to increase the degree of filling of the resulting paste-like compositions while maintaining a low level of their viscosity. The dynamic viscosity of the compositions was evaluated in the range of the shear stresses of 1 to 30 kPa and the temperatures of 293 to 323 K by using a rotary viscometer (cone–plane system). The viscosity of the composition which is a mixture of saturated and unsaturated methyl ester fatty acids at the maximum degree of filling (90 wt.%) was at the level of viscosity of the individual binder. Rheology ; Materials science ; Plasticizer ; Viscometer ; Viscosity ; Natural rubber ; Polymer ; Composite material ; Elastomer ; Composition (language) ; Chemical engineering Thermal and Kinetic Analysis ; Rocket and propulsion systems research ; Polymer Nanocomposites and Properties
Authors: Pietro Dalle Feste | Teresa Gatti | Francesco Lamberti
Source: Zenodo (CERN European Organization for Nuclear Research) (article, 2021-02-25)
Field: Materials Science — Materials Chemistry

Work Function Tuning in Hydrothermally Synthesized Vanadium-Doped MoO3 and Co3O4 Mesostructures for Energy Conversion Devices The wide interest in developing green energy technologies stimulates the scientific community to seek, for devices, new substitute material platforms with a low environmental impact, ease of production and processing and long-term stability. The synthesis of metal oxide (MO) semiconductors fulfils these requirements and efforts are addressed towards optimizing their functional properties through the improvement of charge mobility or energy level alignment. Two MOs have rising perspectives for application in light harvesting devices, mainly for the role of charge selective layers but also as light absorbers, namely MoO<sub>3</sub> (an electron blocking layer) and Co<sub>3</sub>O<sub>4</sub> (a small band gap semiconductor). The need to achieve better charge transport has prompted us to explore strategies for the doping of MoO<sub>3</sub> and Co<sub>3</sub>O<sub>4</sub> with vanadium (V) ions that, when combined with oxygen in V<sub>2</sub>O<sub>5</sub>, produce a high work function MO. We report on subcritical hydrothermal synthesis of V-doped mesostructures of MoO<sub>3</sub> and of Co<sub>3</sub>O<sub>4</sub>, in which a tight control of the doping is exerted by tuning the relative amounts of reactants. We accomplished a full analytical characterization of these V-doped MOs that unambiguously demonstrates the incorporation of the vanadium ions in the host material, as well as the effects on the optical properties and work function. We foresee a promising future use of these materials as charge selective materials in energy devices based on multilayer structures Vanadium ; Doping ; Materials science ; Work function ; Chemical engineering ; Function (biology) ; Nanotechnology ; Optoelectronics ; Metallurgy Catalytic Processes in Materials Science ; Transition Metal Oxide Nanomaterials ; Catalysis and Hydrodesulfurization Studies
Authors: Ronald A. Farrar‐Tobar | Stefan Weber | Zita Csendes | Antonio Ammaturo | Sarah Fleissner | Helmuth Hoffmann | Luı́s F. Veiros | Karl Kirchner
Source:  (preprint, 2021-10-15)
Field: Chemistry — Inorganic Chemistry

Selective Manganese-Catalyzed Semihydrogenation of Alkynes with in-situ Generated H2 from KBH4 and Methanol The selective semihydrogenation of alkynes with the Mn(I) alkyl catalyst fac-[Mn(dippe)(CO)3(CH2CH2CH3)] (dippe = 1,2-bis(di-iso-propylphosphino)ethane) as pre-catalyst is described. Hydrogen gas required for the hydrogenation is generated in situ upon alcoholysis of KBH4 with methanol. A series of aryl-aryl, aryl-alkyl, alkyl-alkyl and terminal alkynes were readily hydrogenated to yield E-alkenes in good to excellent isolated yields. The reaction proceeds at 90°C with catalyst loadings of 0.5 -2 mol%. The implemented protocol tolerates a variety of electron donating and electron withdrawing functional groups including halides, phenols, nitriles, unprotected amines and heterocycles. The reaction can be upscaled to the gram scale. Mechanistic investigations including deuterium labelling studies and DFT calculations were undertaken to provide a reasonable reaction mechanism showing that initially formed Z-isomer undergoes fast isomerization to afford the thermodynamically more stable E-isomer. Isomerization ; Alkyl ; Catalysis ; Aryl ; Chemistry ; Methanol ; Yield (engineering) ; Halide ; Manganese ; Medicinal chemistry ; Organic chemistry ; Materials science Asymmetric Hydrogenation and Catalysis ; RNA modifications and cancer ; Carbon dioxide utilization in catalysis
Authors: Muhammad N. Yousaf
Source:  (preprint, 2021-05-22)
Field: Materials Science — Materials Chemistry

Supramolecular BODIPY Dye Architectures for Advanced Light Harvesting and Energy Transfer Applications Shape-persistent phenylacetylene macrocycles have been explored in a number of optoelectronic and light-harvesting applications, including two-photon absorption. Likewise, BODIPY (4,4-difluoro-4-bora-3a,4a-diaza-s-indacenes) dyes have also been extensively used in material applications, owing to their tunable, intense absorption and sharp emission spectra exhibiting high quantum yields. Combining these two architectures, this thesis presents a derivative where a BODIPY is contained orthogonally within the phenylacetylene-macrocycle. This structure was inspired by photosystem II antennae complexes where energy is obsorbed by antennae complexes and funneled down to a reaction centre. Specifically, this family of molecules uses the phenylacetylene macrocycle to harvest the light and transfer it to the BODIPY core, and this has been observed by examining the fluorescence emission from the BODIPY (Figure 1). This novel dye design if coupled to a donor (D) and acceptor (A) capable of anchoring to TiO2 could be modified to become a π-spacer (i.e. D-π-A motif) for dye-sensitized solar cells resulting in panchromatic absorption, and ultimately more efficient devices. BODIPY ; Phenylacetylene ; Photochemistry ; Fluorescence ; Absorption (acoustics) ; Supramolecular chemistry ; Chemistry ; Materials science ; Molecule ; Optics ; Physics ; Organic chemistry Luminescence and Fluorescent Materials ; Advanced biosensing and bioanalysis techniques ; Organic Electronics and Photovoltaics
Authors: Emanuela Bianchi | Peter D. J. van Oostrum | Christos N. Likos | Gerhard Kahl
Source: arXiv (Cornell University) (preprint, 2021-01-20)
Field: Materials Science — Materials Chemistry

Inverse patchy colloids: synthesis, modeling and self-organization Inverse patchy colloids are nano- to micro-scale particles with a surface divided into differently charged regions. This class of colloids combines directional, selective bonding with a relatively simple particle design: owing to the competitive interplay between the orientation-dependent attraction and repulsion -- induced by the interactions between like/oppositely charged areas -- experimentally accessible surface patterns are complex enough to favor the stabilization of specific structures of interest. Most important, the behavior of heterogeneously charged units can be ideally controlled by means of external parameters, such as the pH and the salt concentration. We present a concise review about this class of systems, spanning the range from the synthesis of model inverse patchy particles to their self-assembly, covering their coarse-grained modeling and the related numerical/analytical treatments. Colloid ; Inverse ; Chemical physics ; Particle (ecology) ; Range (aeronautics) ; Nanotechnology ; Surface (topology) ; Materials science ; Particle system ; Simple (philosophy) ; Colloidal particle ; Statistical physics ; Biological system ; Physics ; Chemistry ; Computer science ; Geometry ; Mathematics ; Geology ; Physical chemistry ; Composite material Pickering emulsions and particle stabilization ; Surfactants and Colloidal Systems ; Electrostatics and Colloid Interactions
Authors: Feng Tao
Source: Scholarworks (University of Massachusetts Amherst) (article, 2021-04-01)
Field: Materials Science — Materials Chemistry

Nanomaterials at Liquid/Liquid Interfaces: Assembly and Rheology The goal of this dissertation is to advance the state of the art of research in constraint-based phonotactics. It takes a two-pronged approach: a technological contribution intended to facilitate future research, and experiments which seek to shed light on high-level questions about the properties of phonotactic models that can guide the development of theoretical work. The technological contribution is a software package called Speriment which allows experimenters to create and run experiments over the internet without advanced programming techniques. This software is particularly well suited to the kinds of experiments often run in phonotactic research, but can also be used for experiments in other domains of linguistics and the social sciences. It is hoped that this software will make it faster and easier to conduct phonotactic and other experiments as well as encourage experimenters to increase the reproducibility and transparency of their research. The experiments presented here address questions that assume constraint-based phonotactic frameworks, but that do not rely on particular theories of the content of the constraint set. That is, they apply to constraint-based frameworks for theories of phonotactics, with the first study seeking to distinguish between two such frameworks, a linear version of Harmonic Grammar and Maximum Entropy, while the second investigates whether phonotactic knowledge is independent of knowledge of phonological alternations. These coarse-grained questions about phonotactic knowledge on how pieces of phonotactic knowledge interact with each other and with another part of the grammar are intended to add to the groundwork on which phonotactic models and models of all phonological knowledge are built. Their findings have implications for which constraint-based frameworks should be used for future theories and how these theories can be reliably tested. Rheology ; Nanomaterials ; Nanotechnology ; Materials science ; Composite material Pickering emulsions and particle stabilization ; Surfactants and Colloidal Systems ; Minerals Flotation and Separation Techniques
Authors: Xia‐Li Ding | Qian‐Cheng Luo | Yuan‐Qi Zhai | Xu‐Feng Zhang | Yi Lyu | Xinliang Zhang | Chao Ke | Yan‐Zhen Zheng
Source: Research Square (preprint, 2021-04-28)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Predesigned rigid dysprosium(III) single-molecule magnets exhibit preserved superparamagnetism in solution Abstract Molecules with long preserved magnetic moments are perceived as the smallest units for storing bytes, which could bring a new revolution for information technology. However, the rational design of such molecules remains challenging. Here we show it is possible to predesign such molecules by studying the vibration spectra. Two adamantanol based dysprosium(III) complexes with pentagonal-bipyramidal local geometry were theoretically predicted to display enhanced single-molecule magnet (SMM) behavior due to the reduced vibration modes in low energy regimes. The experimental isolation of these two complexes not only confirms this prediction, but further reveals almost unchanged large energy barriers and high blocking temperatures in solution state. This is never observed in previous studies of SMMs, indicating that the adamantanol ligand is rigid enough to make the complexes exhibiting intrinsic magnetic property in solution. As vibration spectrometer is routinely accessible in common laboratories this work provides a facile strategy to construct high-performance SMMs. Dysprosium ; Superparamagnetism ; Magnet ; Single-molecule magnet ; Molecule ; Materials science ; Lanthanide ; Crystallography ; Chemistry ; Inorganic chemistry ; Physics ; Organic chemistry ; Magnetization ; Magnetic field ; Quantum mechanics Magnetism in coordination complexes ; Lanthanide and Transition Metal Complexes ; Advanced NMR Techniques and Applications
Authors: Subhasish Roy
Source: Prayogik Rasayan (article, 2021-01-01)
Field: Materials Science — Biomaterials

Dipeptide-SWCNTs-based Supramolecular Hybrid Hydrogel A dipeptide appended pyrenebutyric acid’s amide forms hydrogel at basic pH (pH of the gelator dissolved solution ~ 13.7 at 25 °C temperature) with an estimated minimum gelation concentration (MGC) of 0.29 % w/v. The hydrogel was characterized meticulously by using various microscopic and spectroscopic techniques including Transmission Electron Microscopy (TEM), Field Emission Scanning Electron Microscopicy (FE-SEM), X-ray diffraction, fluorescence spectroscopy and rheology. The hydrogel exhibits bluish green fluorescence emission colour. The gelator molecule itself can disperse pristine-single walled carbon nanotubes (SWCNTs) in basic aqueous medium and it can also form a hybrid hydrogel with SWCNTs under the hydrogelation condition. Fluorescence, morphological and rheological properties of the hybbrid hydrogel are also different from the native hydrogel. Dipeptide ; Rheology ; Self-healing hydrogels ; Carbon nanotube ; Materials science ; Transmission electron microscopy ; Fluorescence ; Chemical engineering ; Aqueous solution ; Scanning electron microscope ; Molecule ; Amide ; Nanotechnology ; Polymer chemistry ; Chemistry ; Organic chemistry ; Composite material ; Peptide ; Optics Supramolecular Self-Assembly in Materials ; Chemical Synthesis and Analysis ; Glycosylation and Glycoproteins Research