jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Audra J. DeStefano | Jiashi Yin | Theodore J. Kraus | B. A. Parkinson | Katie Li-Oakey
Source: ACS Omega (article, 2018-09-05)
Field: Materials Science — Surfaces, Coatings and Films

Elucidation of Titanium Dioxide Nucleation and Growth on a Polydopamine-Modified Nanoporous Polyvinylidene Fluoride Substrate via Low-Temperature Atomic Layer Deposition Interfaces combining polydopamine (PDA) and nanoparticles have been widely utilized for fabricating hybrid colloidal particles, thin films, and membranes for applications spanning biosensing, drug delivery, heavy metal detection, antifouling membranes, and lithium ion batteries. However, fundamental understanding of the interaction between PDA and nanoparticles is still limited, especially the impact of PDA on nanoparticle nucleation and growth. In this work, PDA is used to generate functional bonding sites for depositing titanium dioxide (TiO<sub>2</sub>) via atomic layer deposition (ALD) onto a nanoporous polymer substrate for a range of ALD cycles (<100). The resulting hybrid membranes are systematically characterized using water contact angle, scanning electron microscopy, atomic force microscopy, nitrogen adsorption and desorption, and X-ray photoelectron spectroscopy (XPS). An intriguing nonlinear relationship was observed between the number of ALD cycles and changes in surface properties (water contact angle and surface roughness). Together with XPS study, those changes in surface properties were exploited to probe the nanoparticle nucleation and growth process on complex PDA-coated porous polymer substrates. Molecular level understanding of inorganic and polymer material interfaces will shed light on fine-tuning nanoparticle-modified polymeric membrane materials. Materials science ; Nanoporous ; Chemical engineering ; Atomic layer deposition ; X-ray photoelectron spectroscopy ; Nanoparticle ; Nucleation ; Polyvinylidene fluoride ; Contact angle ; Anatase ; Titanium dioxide ; Surface modification ; Nanotechnology ; Polymer ; Substrate (aquarium) ; Membrane ; Thin film ; Photocatalysis ; Chemistry ; Composite material ; Organic chemistry Polymer Surface Interaction Studies ; Advanced Sensor and Energy Harvesting Materials ; Graphene research and applications
Authors: Chairul Hudaya | Minjeh Ahn | Si Hyoung Oh | Bup Ju Jeon | Yung‐Eun Sung | Joong Kee Lee
Source: Journal of Industrial and Engineering Chemistry (article, 2018-02-16)
Field: Materials Science — Materials Chemistry

Simultaneous etching and transfer — Free multilayer graphene sheets derived from C60 thin films Graphene ; Materials science ; Chemical vapor deposition ; Etching (microfabrication) ; Substrate (aquarium) ; Nanotechnology ; Thin film ; Graphene nanoribbons ; Chemical engineering ; Optoelectronics ; Layer (electronics) Graphene research and applications ; Fullerene Chemistry and Applications ; Thermal properties of materials
Authors: Sorachat Tharamak | Christian Knittl‐Frank | Auraya Manaprasertsak | Anchulee Pengsook | Lydia Suchy | Philipp Schuller | Barbara Happl | Alexander Roller | Michael Widhalm
Source: Molecules (article, 2018-03-24)
Field: Chemistry — Organic Chemistry

Economy of Catalyst Synthesis—Convenient Access to Libraries of Di- and Tetranaphtho Azepinium Compounds Efficient optimization procedures in chiral catalysis are usually linked to a straightforward strategy to access groups of structurally similar catalysts required for fine-tuning. The ease of building up such ligand libraries can be increased when the structure-modifying step (introduction of a substituent) is done at a later stage of the synthesis. This is demonstrated for the extended family of di- and tetranaphtho azepinium compounds, widely used as chiral phase transfer catalysts (PTC). Using 2,6-diiodo-4,5-dihydro-3<i>H</i>-dinaphtho[2,1-c:1',2'-e]azepine and 4,8-diiodo-6,7-dihydro-5<i>H</i>-dibenzo[c,e]azepine, respectively, as key intermediates, 18 <i>spiro</i>-azepinium compounds were synthesized in a total yield of 25-42% over 6-7 steps from 1,1'-binaphthyl-2,2'-dicarboxylic acid or diphenic acid, respectively. The replacement of iodo groups with aryl substituents was performed as the last or the penultimate step of the synthesis. Azepine ; Catalysis ; Yield (engineering) ; Substituent ; Chemistry ; Ligand (biochemistry) ; Combinatorial chemistry ; Aryl ; Medicinal chemistry ; Stereochemistry ; Organic chemistry ; Materials science ; Receptor Axial and Atropisomeric Chirality Synthesis ; Asymmetric Synthesis and Catalysis ; Alkaloids: synthesis and pharmacology
Authors: S. Vidya | J. Thomas
Source: Bulletin of Pure & Applied Sciences- Chemistry (article, 2018-01-01)
Field: Materials Science — Materials Chemistry

Optical and dielectric investigations of nano crystalline scheelite A0.5B0.5MoO4 (A=B=Ba, Sr and Ca) The synthesis of nanocrystalline A0.5B0.5MoO4 by an auto-igniting combustion technique is reported. The structural characterization done by X-ray diffraction, Fourier transform Raman spectroscopy and infrared spectroscopy reveals that the as-prepared powder itself is phase pure with tetragonal structure. The particle size determined from Transmission electron microscopy are in the range 23–25 nm. The optical band gap determined show that the compounds are wide bandgap semiconductors. The photoluminescence spectrum of A0.5B0.5MoO4 shows green emission, associated with the perfect order and crystallinity of the sample. All the samples are sintered at a temperature less than 875°C. The dielectric constant and loss factor of the samples are measured at radiofrequency range and its variation with temperature is also studied. The effect of change in composition of A2+ site of scheelite AMO4 compounds comparative are also presented. The experimental results show that nano A0.5B0.5MoO4 is an excellent luminescent material and also a promising ‘Low temperature Co-fired Ceramic. Also it is inferred that we can fine tune both optical and dielectric properties to desired values according to our requirements by adjusting the cationic stoichiometric ratio in [AO8] octahedron. Scheelite ; Dielectric ; Materials science ; Nano- ; Crystallography ; Mineralogy ; Chemistry ; Optoelectronics ; Metallurgy ; Tungsten ; Composite material Luminescence Properties of Advanced Materials ; Microwave Dielectric Ceramics Synthesis ; Nuclear materials and radiation effects
Authors: Henry Proudhon | Nicolas Guéninchault | Samuel Forest | Wolfgang Ludwig
Source: Preprints.org (preprint, 2018-09-10)
Field: Materials Science — Materials Chemistry

Incipient Bulk Polycrystal Plasticity Observed by Synchrotron in-situ Topotomography In this paper, we present a comprehensive 4D study of the early stage of plastic deformation in a polycrystalline binary AlLi alloy. The entire microstructure is mapped with X-ray diffraction contrast tomography and a set of bulk grains is further studied via X-ray topotomography during mechanical loading. The observed contrast is analyzed with respect to the slip system activation and the evolution of the orientation spread is measured as a function of applied strain. The experimental observations are augmented by the mechanical response predicted by crystal plasticity finite element simulations to analyze the onset of plasticity in details. Simulation results show a general agreement of the individual slip system activation during loading and that comparison with experiments at the length scale of the grains may be used to fine tune the constitutive model parameters. Plasticity ; Crystal plasticity ; Materials science ; Synchrotron ; Crystallite ; Slip (aerodynamics) ; Microstructure ; Finite element method ; Diffraction ; In situ ; Deformation (meteorology) ; Crystallography ; Composite material ; Structural engineering ; Metallurgy ; Thermodynamics ; Optics ; Physics ; Engineering ; Chemistry Microstructure and mechanical properties ; Metallurgy and Material Forming ; Metal Forming Simulation Techniques
Authors: Siwei Liang | Longjiang Li
Source: Journal of Applied Physics (article, 2018-03-16)
Field: Materials Science — Materials Chemistry

Improved thermoelectric performance of CdO by adding SiC fibers versus by adding SiC nanoparticles inclusions We report the improved thermoelectric (TE) performance of CdO by alloying with SiC fibers. In contrast to the lowered thermoelectric figure of merit (ZT) in a CdO matrix with SiC nanoparticle composites, an appreciable ZT value increment of about 36% (from 0.32 to 0.435) at 1000 K was obtained in the CdO matrix with SiC fiber composites. Both kinds of composites show substantially decreased thermal conductivity due to additional phonon scattering by the nano-inclusions. Compared to the very high electrical resistivity (ρ ∼ 140 μΩ m) for 5 at. % SiC nanoparticle composites, SiC fiber composites favorably maintained a very low ρ (∼30 μΩ m) even with 5 at. % SiC at 1000 K. We think the substantial difference of specific surface areas of these two nano-inclusions (30 m2/g for fibers vs 300 m2/g for nanoparticles) might play a crucial role to fine tune the TE performance. Larger interface could be inductive to diffusion and electron acceptor activation, which affect carrier mobility considerably. This work might hint at an alternative approach to improve TE materials' performance. Materials science ; Thermoelectric effect ; Nanoparticle ; Composite material ; Electrical resistivity and conductivity ; Figure of merit ; Thermal conductivity ; Phonon scattering ; Fiber ; Thermoelectric materials ; Electron mobility ; Nanotechnology ; Optoelectronics Advanced Thermoelectric Materials and Devices ; Chalcogenide Semiconductor Thin Films ; Heusler alloys: electronic and magnetic properties
Authors: Arjan W. Kleij
Source: Chem (article, 2018-05-01)
Field: Chemistry — Inorganic Chemistry

Cooperative Catalysis for an Asymmetric Cascade toward α-Quaternary Aldehydes Allylic rearrangement ; Catalysis ; Chemistry ; Syngas ; Combinatorial chemistry ; Enantioselective synthesis ; Cascade reaction ; Kinetic resolution ; Organic synthesis ; Organic chemistry Asymmetric Hydrogenation and Catalysis ; Catalysis for Biomass Conversion ; Carbon dioxide utilization in catalysis
Authors: Yousuke Ooyama
Source: Journal of Synthetic Organic Chemistry Japan (article, 2018-10-01)
Field: Materials Science — Materials Chemistry

Mechanofluorochromism of D-π-A Fluorescent Dyes Mechanofluorochromic dyes can exhibit a change in fluorescent colour by external mechanical stimuli to the solids, being accompanied by a reversion to the original fluorescent color by heating or exposure to solvent vapor, which have attracted much attention from chemists, physicists, and engineers because of enormous scientific interest in the fundamental research fields of photochemistry and photophysics and interesting smart materials for next generation optoelectronic devices. We have found that newly developed heteropolycyclic donor-acceptor π-conjugated (D-π-A) fluorescent dyes with electron-withdrawing substituents as acceptor show a bathochromic shift-type mechanofluorochromism (MFC). Our work revealed that the MFC of D-π-A fluorescent dyes is attributed to a reversible switching between crystalline and amorphous states with changes of dipole-dipole interaction and intermolecular π-π interaction. We propose that the most important point for developing MFC dyes is to design D-π-A fluorescent dye molecules with moderate dipole moments (ca. 5 Debye) which are controlled by tuning the electron-donating ability of D, electron-accepting ability of A, steric size of a substituent, and D-π-A system. On the other hand, we demonstrated that the bathochromic shift-type MFC of unsymmetrical carbazole-type D-π-A fluorescent dyes is attributed to a reversible switching between crystalline and amorphous states with changes of intermolecular hydrogen bonding and π-π interaction. We also propose that the use of various counter anions for D-π-A pyridinium dyes can be one of the most effective strategies, not only to express a pronounced MFC, but also to control changes of fluorescence properties by the grinding and heating, resulting in fine-tuning of fluorescent color change by the MFC. Bathochromic shift ; Fluorescence ; Photochemistry ; Intermolecular force ; Amorphous solid ; Acceptor ; Electron acceptor ; Chemistry ; Electron donor ; Substituent ; Intramolecular force ; Hydrogen bond ; Solvatochromism ; Dipole ; Molecule ; Materials science ; Chemical physics ; Crystallography ; Organic chemistry ; Optics Luminescence and Fluorescent Materials ; Photochromic and Fluorescence Chemistry ; Polydiacetylene-based materials and applications
Authors: Hossein Roohi | Hamead Reza Sherkhani | Homaera Mahbob
Source: Journal of Luminescence (article, 2018-08-07)
Field: Chemistry — Physical and Theoretical Chemistry

Fine-tuning the photophysical properties of the five quinolin based nanophotoswitches in the gas phase, polar and nonpolar solvents: A TD-DFT approach Excited state ; Density functional theory ; Intramolecular force ; Chemistry ; Dipole ; Fluorescence ; Tautomer ; Stokes shift ; Molecule ; Photochemistry ; Ground state ; Oscillator strength ; Time-dependent density functional theory ; Absorption (acoustics) ; Computational chemistry ; Atomic physics ; Materials science ; Optics ; Spectral line ; Stereochemistry Photochemistry and Electron Transfer Studies ; Luminescence and Fluorescent Materials ; Porphyrin and Phthalocyanine Chemistry
Authors: Roman Morozov | В. В. Авдин | Igor Krivtsov | A. M. Gorshkov | A.V. Urzhumova | A. Osinskaya | D. Yuzhalkin
Source: Bulletin of the South Ural State University series Chemistry (article, 2018-01-01)
Field: Chemistry — Organic Chemistry

Modification with Amino Groups of Composite SiO2–TiO2 and Pure TiO2 Spheres Prepared via the Peroxo Route A series of porous composite SiO 2 –TiO 2 and pure TiO 2 spherical particles were prepared via the peroxo route and subsequently used as the support for catalyst. Aminopropyltrimethoxysilane (APTMS) was grafted to the surface of support in the strictly unhydrous media leading to bonding of free amino groups to the support surface covalently. Procedure of APTMS grafting is easy to perform and may be spread for grafting other different functional groups to the inorganic surfaces of the catalyst support. The support samples were calcined at various temperatures in order to optimize the preparation conditions and boost the density of surface amino groups. It has been found that the quantity of grafted APTMS varies insignificantly for the different support samples. Grafted amino groups would be applied as active catalytic sites in different reactions of organic chemistry such as acylation of amines and alcohols, polymerization of lactones with hydroxyl groups, isomerization of unsaturated compounds, aldol condensation, Diels-Alder, Michael, Knoevenagel reactions. The mechanisms of reaction activation by amino groups are the transfer of electron density to a reacting molecule and formation of an intermediate complex. While widely applied catalysts are liquid amines, it is desirable to transform these substances into the heterogeneous form for better regeneration and purification of reaction products from the initial reagents. Prepared catalysts exhibit high amino groups load equal to 1 mmol/g, taking into account the localization of amino groups on the surface of the catalyst. Catalysis ; Reagent ; Chemistry ; Isomerization ; Acylation ; Surface modification ; Knoevenagel condensation ; Covalent bond ; Polymer chemistry ; Organic chemistry ; Chemical engineering ; Physical chemistry Chemical Synthesis and Reactions ; Polyoxometalates: Synthesis and Applications ; Mesoporous Materials and Catalysis
Authors: Nan Zhang | Xiaoqing Cong
Source: Materials Sciences and Applications (article, 2018-01-01)
Field: Materials Science — Materials Chemistry

Enhanced Nonlinear Absorption Performance of Reduced Graphene Oxide Nanohybrid Covalently Functionalized by Porphyrin via 1,3-Dipolar Cycloaddition Porphyrin-functionalized reduced graphene oxide (RGO-TPP) was prepared by 1,3-dipolar cycloaddition reaction and characterized by Fourier transform infrared spectroscopy, Raman, ultraviolet/visible absorption, fluorescence, and transmission electron microscopy. At the same level of linear transmittance, RGO-TPP exhibited more enhanced optical nonlinearities than RGO and the pristineporphyrin, implying a remarkable accumulation effect as a result of the covalent link between RGO and porphyrin. The role of energy/electron transfer in the optical nonlinearities of RGO-TPP was investigated by fluorescence and Raman spectroscopy. All the results displayed that RGO can be covalently functionalized with porphyrins by the proposed approach. Materials science ; Graphene ; Porphyrin ; Oxide ; Covalent bond ; Absorption (acoustics) ; Cycloaddition ; Photochemistry ; Dipole ; Nanotechnology ; Chemical engineering ; Organic chemistry ; Composite material ; Catalysis Graphene research and applications ; Nonlinear Optical Materials Studies ; Porphyrin and Phthalocyanine Chemistry
Authors: Alessandro Pedrini | Federico Bertani | Enrico Dalcanale
Source: Molecules (article, 2018-10-17)
Field: Chemistry — Organic Chemistry

Fluorinated Tetraphosphonate Cavitands Two synthetic protocols for the introduction of fluorine atoms into resorcinarene-based cavitands, at the lower and upper rim, respectively, are reported. Cavitand <b>1</b>, bearing four fluorocarbon tails, and cavitand <b>2</b>, which presents a fluorine atom on the <i>para</i> position of a diester phosphonate phenyl substituent, were synthesized and their complexation abilities toward the model guest sarcosine methyl ester hydrochloride were evaluated via NMR titration experiments. The effect of complexation on the <sup>19</sup>F NMR resonance of the probe is evident only in the case of cavitand <b>2</b>, where the inset of the cation-dipole and H-bonding interactions between the P=O bridges and the guest is reflected in a sizable downfield shift of the fluorine probe. Cavitand ; Chemistry ; Resorcinarene ; Substituent ; Phosphonate ; Fluorine ; Fluorine-19 NMR ; Calixarene ; Computational chemistry ; Nuclear magnetic resonance spectroscopy ; Stereochemistry ; Organic chemistry ; Supramolecular chemistry ; Molecule Supramolecular Chemistry and Complexes ; Molecular Sensors and Ion Detection ; Porphyrin and Phthalocyanine Chemistry
Authors: Siva Sankar Murthy Bandaru | Darinka Dzubiel | Heiko Ihmels | Mohebodin Karbasiyoun | Mohamed M A Mahmoud | Carola Schulzke
Source: Beilstein Journal of Organic Chemistry (article, 2018-07-23)
Field: Chemistry — Organic Chemistry

Synthesis of 9-arylalkynyl- and 9-aryl-substituted benzo[<i>b</i>]quinolizinium derivatives by Palladium-mediated cross-coupling reactions 9-Arylbenzo[<i>b</i>]quinolizinium derivatives were prepared with base-free Suzuki-Miyaura coupling reactions between benzo[<i>b</i>]quinolizinium-9-trifluoroborate and selected benzenediazonium salts. In addition, the Sonogashira coupling reaction between 9-iodobenzo[<i>b</i>]quinolizinium and the arylalkyne derivatives yielded four novel 9-(arylethynyl)benzo[<i>b</i>]quinolizinium derivatives under relatively mild reaction conditions. The 9-(<i>N</i>,<i>N</i>-dimethylaminophenylethynyl)benzo[<i>b</i>]quinolizinium is only very weakly emitting, but the emission intensity increases by a factor >200 upon protonation, so that this derivative may operate as pH-sensitive light-up probe. Photometric and fluorimetric titrations of duplex and quadruplex DNA to 9-(arylethynyl)benzo[<i>b</i>]quinolizinium derivatives revealed a significant binding affinity of these compounds towards both DNA forms with binding constants of <i>K</i><sub>b</sub> = 0.2-2.2 × 10<sup>5</sup> M<sup>-1</sup>. Chemistry ; Sonogashira coupling ; Protonation ; Palladium ; Aryl ; Medicinal chemistry ; Combinatorial chemistry ; Titration ; Stereochemistry ; Ion ; Organic chemistry ; Catalysis Catalytic Cross-Coupling Reactions ; Catalytic C–H Functionalization Methods ; Radical Photochemical Reactions
Authors: Ha Eun Shim | Sajid Mushtaq | Jongho Jeon
Source: Journal of Visualized Experiments (article, 2018-07-13)
Field: Materials Science — Materials Chemistry

An Efficient Method for Selective Desalination of Radioactive Iodine Anions by Using Gold Nanoparticles-Embedded Membrane Filter Here, we demonstrate a detail protocol for the preparation of nanomaterials-embedded composite membranes and its application to the efficient and ion-selective removal of radioactive iodines. By using citrate-stabilized gold nanoparticles (mean diameter: 13 nm) and cellulose acetate membranes, gold nanoparticle-embedded cellulose acetate membranes (Au-CAM) have easily been fabricated. The nano-adsorbents on Au-CAM were highly stable in the presence of high concentration of inorganic salts and organic molecules. The iodide ions in aqueous solutions could rapidly be captured by this engineered membrane. Through a filtration process using an Au-CAM containing filter unit, excellent removal efficiency (>99%) as well as ion-selective desalination result was achieved in a short time. Moreover, Au-CAM provided good reusability without significant decrease of its performances. These results suggested that the present technology using the engineered hybrid membrane will be a promising process for the large-scale decontamination of radioactive iodine from liquid wastes. Membrane ; Materials science ; Cellulose acetate ; Nanoparticle ; Desalination ; Iodide ; Filtration (mathematics) ; Nanomaterials ; Aqueous solution ; Chemical engineering ; Adsorption ; Colloidal gold ; Cellulose ; Nanofiltration ; Human decontamination ; Nanotechnology ; Chemistry ; Inorganic chemistry ; Organic chemistry ; Waste management Covalent Organic Framework Applications ; Chemical Synthesis and Characterization ; Radioactive element chemistry and processing