jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Katayoon Tabatabaei | Alexandra Holmes | Kathryn A. Newton | Elayaraja Muthuswamy | Roy Sfadia | Sue A. Carter | Susan M. Kauzlarich
Source: Chemistry of Materials (article, 2019-08-29)
Field: Materials Science — Materials Chemistry

Halogen-Induced Crystallinity and Size Tuning of Microwave Synthesized Germanium Nanocrystals The reduction of Ge halides in oleylamine (OAm) provides a simple, yet effective high-yield synthetic route to germanium nanocrystals (NCs). Significant advances based on this approach include size control of Ge NCs, Bi doping of Ge NCs, and synthesis of Ge1–xSnx alloys. It has been shown that the size of Ge NCs can be controlled by the ratio of Ge2+/Ge4+ in the reaction. Here, we show that finer control of absolute size and crystallinity can be achieved by the addition of molecular iodine (I2) and bromine (Br2) to germanium(II) iodide (GeI2). We also show the presence of a Ge–amine–iodide complex and production of hydrogen and ammonia gases as side products of the reduction reaction. All reactions were carried out by microwave-assisted heating at 250 °C for 30 min. I2 and Br2 are shown to oxidize GeI2 to GeI4 in situ, providing good control over size and crystallinity. The kinetics of Br2 oxidation of GeI2 is slightly different, but both I2 and Br2 provide size control of the Ge NCs. The samples are highly crystalline as indicated by powder X-ray diffraction, selected area electron diffraction, transmission electron microscopy and Raman spectroscopy. Although both I2 and Br2 improve the crystallinity of the Ge NCs, I2 provides overall higher crystallinity in the NCs compared to Br2. Absorption (UV–vis–NIR) spectroscopy is consistent with quantum confinement for Ge NCs. The solutions of I2, GeI2, and colloidal Ge NCs were investigated with Fourier transform infrared and 1H NMR spectroscopies and showed no evidence for imine or nitrile formation. The hydrogen on the amine in OAm is shifted downfield with increasing amounts of I2, consistent with a more acidic ammonium species. Hydrogen and ammonia gases were detected after the reaction by gas chromatography and high-resolution mass spectrometry. The presence of a Ge–amine–iodide complex was also confirmed with no evidence for a hydrazine-like species. These results provide an efficient fine-tuning of size and crystallinity of Ge NCs using halogens in addition to the mixed-valence precursor synthetic protocol previously reported and demonstrate the formation of hydrogen as a reducing agent in OAm. Crystallinity ; Germanium ; Oleylamine ; Nanocrystal ; Materials science ; Raman spectroscopy ; Halogen ; Fourier transform infrared spectroscopy ; Analytical Chemistry (journal) ; Chemistry ; Crystallography ; Nanotechnology ; Chemical engineering ; Organic chemistry ; Silicon ; Optoelectronics ; Optics ; Alkyl Silicon Nanostructures and Photoluminescence ; Semiconductor materials and interfaces ; Quantum Dots Synthesis And Properties
Authors: Demetra Giuri | Marianna Barbalinardo | Nicola Zanna | Paolo Paci | Marco Montalti | Massimiliano Cavallini | Francesco Valle | Matteo Calvaresi | Claudia Tomasini
Source: Molecules (article, 2019-11-28)
Field: Materials Science — Biomaterials

Tuning Mechanical Properties of Pseudopeptide Supramolecular Hydrogels by Graphene Doping Supramolecular hydrogels, obtained from small organic molecules, may be advantageous over polymeric ones for several applications, because these materials have some peculiar properties that differentiate them from the traditional polymeric hydrogels, such as elasticity, thixotropy, self-healing propensity, and biocompatibility. We report here the preparation of strong supramolecular pseudopeptide-based hydrogels that owe their strength to the introduction of graphene in the gelling mixture. These materials proved to be strong, stable, thermoreversible and elastic. The concentration of the gelator, the degree of graphene doping, and the nature of the trigger are crucial to get hydrogels with the desired properties, where a high storage modulus coexists with a good thixotropic behavior. Finally, NIH-3T3 cells were used to evaluate the cell response to the presence of the most promising hydrogels. The hydrogels biocompatibility remains good, if a small degree of graphene doping is introduced. Self-healing hydrogels ; Biocompatibility ; Materials science ; Thixotropy ; Graphene ; Supramolecular chemistry ; Nanotechnology ; Chemical engineering ; Elasticity (physics) ; Elastic modulus ; Molecule ; Polymer chemistry ; Composite material ; Chemistry ; Organic chemistry Supramolecular Self-Assembly in Materials ; Graphene and Nanomaterials Applications ; Photochromic and Fluorescence Chemistry
Authors: Cristiana Fernandes | Geetha B. Heggannavar | Mahadevappa Y. Kariduraganavar | Geoffrey R. Mitchell | Nuno Alves | Pedro Morouço
Source: Applied Mechanics and Materials (article, 2019-04-01)
Field: Materials Science — Polymers and Plastics

Smart Materials for Biomedical Applications: The Usefulness of Shape-Memory Polymers This review describes available smart biomaterials for biomedical applications. Biomaterials have gained special attention because of their characteristics, along with biocompatibility, biodegradability, renewability, and inexpensiveness. In addition, they are also sensitive towards various stimuli such as temperature, light, magnetic, electro, pH and can respond to two or more stimuli at the same time. In this manuscript, the suitability of stimuli-responsive smart polymers was examined, providing examples of its usefulness in the biomedical applications. Biocompatibility ; Materials science ; Smart material ; Shape-memory polymer ; Nanotechnology ; Smart polymer ; Polymer ; Biomedical engineering ; Engineering ; Composite material ; Metallurgy Polymer composites and self-healing ; Advanced Sensor and Energy Harvesting Materials ; Conducting polymers and applications
Authors: Matteo Savastano | Celeste García-Gallarín | Claudia Giorgi | Paola Gratteri | María Dolores López de la Torre | Carla Bazzicalupi | Antonio Bianchi | Manuel Melguizo
Source: Molecules (article, 2019-06-16)
Field: Chemistry — Spectroscopy

Solid State and Solution Study on the Formation of Inorganic Anion Complexes with a Series of Tetrazine-Based Ligands Four molecules (L1-L4) constituted by an s-tetrazine ring appended with two identical aliphatic chains of increasing length bearing terminal morpholine groups were studied as anion receptors in water. The basicity properties of these molecules were also investigated. Speciation of the anion complexes formed in solution and determination of their stability constants were performed by means of potentiometric (pH-metric) titrations, while further information was obtained by NMR and isothermal titration calorimetry (ITC) measurements. The crystal structures of two neutral ligands (L3, L4) and of their H<sub>2</sub>L3(ClO<sub>4</sub>)<sub>2</sub>∙2H<sub>2</sub>O, H<sub>2</sub>L4(ClO<sub>4</sub>)<sub>2</sub>∙2H<sub>2</sub>O, H<sub>2</sub>L3(PF<sub>6</sub>)<sub>2</sub>, and H<sub>2</sub>L3(PF<sub>6</sub>)<sub>2</sub>∙2H<sub>2</sub>O anion complexes were determined by single crystal X-ray diffraction. The formation of anion-π interactions is the leitmotiv of these complexes, both in solution and in the solid state, although hydrogen bonding and/or formation of salt-bridges can contribute to their stability. Evidence of the ability of these ligands to form anion-π interactions is given by the observation that even the neutral (not-protonated) molecules bind anions in water to form complexes of significant stability, including elusive OH<sup>-</sup> anions. Chemistry ; Potentiometric titration ; Tetrazine ; Protonation ; Molecule ; Crystallography ; Hydrogen bond ; Titration ; Isothermal microcalorimetry ; Ion ; Cryptand ; Isostructural ; Isothermal titration calorimetry ; Crystal structure ; Stereochemistry ; Inorganic chemistry ; Physical chemistry ; Enthalpy ; Organic chemistry Molecular Sensors and Ion Detection ; DNA and Nucleic Acid Chemistry ; Crystallography and molecular interactions
Authors: Ayomide H. Labulo | Bernard Omondi | Vincent O. Nyamori
Source: SN Applied Sciences (article, 2019-01-02)
Field: Chemistry — Organic Chemistry

Graphene/pyrrolic-structured nitrogen-doped CNT nanocomposite supports for Pd-catalysed Heck coupling and chemoselective hydrogenation of nitroarenes Nanocomposite ; Materials science ; Graphene ; Catalysis ; Carbon nanotube ; Chemical engineering ; Palladium ; Selectivity ; Raman spectroscopy ; Oxide ; Inorganic chemistry ; Nanotechnology ; Chemistry ; Organic chemistry ; Metallurgy Nanomaterials for catalytic reactions ; Graphene research and applications ; Ammonia Synthesis and Nitrogen Reduction
Authors: Lubna Ghani | Chastine F. Munk | Xiang Zhang | Satoshi Katsube | Yang Du | Cristina Cecchetti | Weijiao Huang | Hyoung Eun Bae | Savvas Saouros | Muhammad Ehsan | Lan Guan | Xiangyu Liu | Claus J. Løland | Brian K. Kobilka | Bernadette Byrne | Pil Seok Chae
Source: Journal of the American Chemical Society (article, 2019-12-06)
Field: Chemistry — Organic Chemistry

1,3,5-Triazine-Cored Maltoside Amphiphiles for Membrane Protein Extraction and Stabilization Despite their major biological and pharmacological significance, the structural and functional study of membrane proteins remains a significant challenge. A main issue is the isolation of these proteins in a stable and functional state from native lipid membranes. Detergents are amphiphilic compounds widely used to extract membrane proteins from the native membranes and maintain them in a stable form during downstream analysis. However, due to limitations of conventional detergents, it is essential to develop novel amphiphiles with optimal properties for protein stability in order to advance membrane protein research. Here we designed and synthesized 1,3,5-triazine-cored dimaltoside amphiphiles derived from cyanuric chloride. By introducing variations in the alkyl chain linkage (ether/thioether) and an amine-functionalized diol linker (serinol/diethanolamine), we prepared two sets of 1,3,5-triazine-based detergents. When tested with several model membrane proteins, these agents showed remarkable efficacy in stabilizing three transporters and two G protein-coupled receptors. Detergent behavior substantially varied depending on the detergent structural variation, allowing us to explore detergent structure-property-efficacy relationships. The 1,3,5-triazine-based detergents introduced here have significant potential for membrane protein study as a consequence of their structural diversity and universal stabilization efficacy for several membrane proteins. Chemistry ; Amphiphile ; Membrane ; Cyanuric chloride ; Membrane protein ; Triazine ; Integral membrane protein ; Thioether ; Combinatorial chemistry ; Amine gas treating ; Organic chemistry ; Biochemistry ; Polymer Click Chemistry and Applications ; RNA Interference and Gene Delivery ; Synthesis and Characterization of Heterocyclic Compounds
Authors: Tim Verhagen | Barbara Pacáková | Milan Bouša | Uwe Hübner | Martin Kalbáč | Jana Vejpravová | Otakar Frank
Source: Scientific Reports (article, 2019-07-10)
Field: Materials Science — Materials Chemistry

Superlattice in collapsed graphene wrinkles Abstract Topographic corrugations, such as wrinkles, are known to introduce diverse physical phenomena that can significantly modify the electrical, optical and chemical properties of two-dimensional materials. This range of assets can be expanded even further when the crystal lattices of the walls of the wrinkle are aligned and form a superlattice, thereby creating a high aspect ratio analogue of a twisted bilayer or multilayer – the so-called twisted wrinkle. Here we present an experimental proof that such twisted wrinkles exist in graphene monolayers on the scale of several micrometres. Combining atomic force microscopy and Raman spectral mapping using a wide range of visible excitation energies, we show that the wrinkles are extremely narrow and their Raman spectra exhibit all the characteristic features of twisted bilayer or multilayer graphene. In light of a recent breakthrough – the superconductivity of a magic-angle graphene bilayer, the collapsed wrinkles represent naturally occurring systems with tuneable collective regimes. Graphene ; Superlattice ; Bilayer graphene ; Raman spectroscopy ; Materials science ; Bilayer ; Monolayer ; Superconductivity ; Nanotechnology ; Condensed matter physics ; Optoelectronics ; Optics ; Chemistry ; Physics ; Membrane Graphene research and applications ; Metamaterials and Metasurfaces Applications ; Advanced Materials and Mechanics
Authors: Jaanus Kruusma | Arvo Tõnisoo | Rainer Pärna | E. Nõmmiste | Enn Lust
Source: Nanomaterials (article, 2019-02-22)
Field: Materials Science — Polymers and Plastics

In Situ X-ray Photoelectron Spectroscopic and Electrochemical Studies of the Bromide Anions Dissolved in 1-Ethyl-3-Methyl Imidazolium Tetrafluoroborate Influence of electrode potential on the electrochemical behavior of a 1-ethyl-3-methylimidazolium tetrafluoroborate (EMImBF₄) solution containing 5 wt % 1-ethyl-3-methylimidazolium bromide (EMImBr) has been investigated using electrochemical and synchrotron-initiated high-resolution in situ X-ray photoelectron spectroscopy (XPS) methods. Observation of the Br 3d<sub>5/2</sub> in situ XPS signal, collected in a 5 wt % EMImBr solution at an EMImBF₄⁻vacuum interface, enabled the detection of the start of the electrooxidation process of the Br⁻ anion to Br₃⁻ anion and thereafter to the Br₂ at the micro-mesoporous carbon electrode, polarized continuously at the high fixed positive potentials. A new photoelectron peak, corresponding to B⁻O bond formation in the B 1s in situ XPS spectra at <i>E</i> ≤ ⁻1.17 V, parallel to the start of the electroreduction of the residual water at the micro-mesoporous carbon electrode, was observed and is discussed. The electroreduction of the residual water caused a reduction in the absolute value of binding energy vs. potential plot slope twice to ca. d<i>BE</i> d<i>E</i><sup>-1</sup> = ⁻0.5 eV V<sup>-1</sup> at <i>E</i> ≤ ⁻1.17 V for C 1s, N 1s, B 1s, F 1s, and Br 3d<sub>5/2</sub> photoelectrons. X-ray photoelectron spectroscopy ; Tetrafluoroborate ; Ionic liquid ; Bromide ; Electrochemistry ; Chemistry ; Electrode ; Binding energy ; Analytical Chemistry (journal) ; Inorganic chemistry ; Materials science ; Physical chemistry ; Catalysis ; Organic chemistry ; Chemical engineering Conducting polymers and applications ; Supercapacitor Materials and Fabrication ; Transition Metal Oxide Nanomaterials
Authors: Faezeh Sabri | Kevin Berthomier | Changsheng Wang | Louis Fradette | Jason R. Tavares | Nick Virgilio
Source: Green Chemistry (article, 2019-01-01)
Field: Materials Science — Materials Chemistry

Tuning particle–particle interactions to control Pickering emulsions constituents separation This work demonstrates how grafting natural polysaccharides, herein sodium alginate, on a particle surface enhances the separation of Pickering emulsion constituents. Pickering emulsion ; Particle (ecology) ; Separation (statistics) ; Chemical engineering ; Chemistry ; Materials science ; Nanotechnology ; Emulsion ; Organic chemistry ; Computer science ; Engineering ; Biology Pickering emulsions and particle stabilization ; Proteins in Food Systems ; Hydrogels: synthesis, properties, applications
Authors: Yong Hyun Lee | So Yeon Park | Jae Eun Park | Byung Ok Jung | Jung Eun Park | Jae Kweon Park | You Jin Hwang
Source: International Journal of Molecular Sciences (article, 2019-06-24)
Field: Materials Science — Biomaterials

Anti-Oxidant Activity and Dust-Proof Effect of Chitosan with Different Molecular Weights High molecular weight chitosan (HMWC) was degraded to prepare chitosan with different molecular weight based on the fenton reaction, which can produce aggressive OH-radicals produced from hydrogen peroxide in the presence of catalytic metal ions. The relative molecular weight, anti-oxidant activity, and fine dust removal effect of chitosan hydrolysates were elucidated to define their molecular weight and their potent biological activity. Our results demonstrate that chitosan hydrolysates derived from the hydrolysis of HMWC may possess significant free-radical scavenging activity as good anti-oxidants against the radical scavenging activity of DPPH and ABTS, respectively. Furthermore, chitosan hydrolysates can effectively eliminate fine dust, which may contain some particulate matter (PM) and unknown species of microorganisms from the air, suggesting that our data provide important information for producing air filters, dust-proof masks and skin cleaner for the purpose of human healthcare and well-being. Chitosan ; Chemistry ; ABTS ; DPPH ; Hydrolysate ; Hydrogen peroxide ; Radical ; Hydrolysis ; Antioxidant ; Particulates ; Organic chemistry Nanocomposite Films for Food Packaging ; Nanoparticles: synthesis and applications ; Air Quality and Health Impacts
Authors: Marion Kieffer | Ana M. García | Cally J. E. Haynes | Slavko Kralj | Daniel Iglesias | Jonathan R. Nitschke | Silvia Marchesan
Source: Angewandte Chemie (article, 2019-03-28)
Field: Materials Science — Biomaterials

Embedding and Positioning of Two Fe<sup>II</sup><sub>4</sub>L<sub>4</sub> Cages in Supramolecular Tripeptide Gels for Selective Chemical Segregation Abstract An unreported d,l ‐tripeptide self‐assembled into gels that embedded Fe II 4 L 4 metal–organic cages to form materials that were characterized by TEM, EDX, Raman spectroscopy, rheometry, UV/Vis and NMR spectroscopy, and circular dichroism. The cage type and concentration modulated gel viscoelasticity, and thus the diffusion rate of molecular guests through the nanostructured matrix, as gauged by 19 F and 1 H NMR spectroscopy. When two different cages were added to spatially separated gel layers, the gel–cage composite material enabled the spatial segregation of a mixture of guests that diffused into the gel. Each cage selectively encapsulated its preferred guest during diffusion. We thus present a new strategy for using nested supramolecular interactions to enable the separation of small molecules. Supramolecular chemistry ; Tripeptide ; Spectroscopy ; Crystallography ; Chemistry ; Nuclear magnetic resonance spectroscopy ; Molecule ; Raman spectroscopy ; Circular dichroism ; Diffusion ; Stereochemistry ; Organic chemistry ; Peptide Supramolecular Self-Assembly in Materials ; Supramolecular Chemistry and Complexes ; Chemical Synthesis and Analysis
Authors: Hadi Parsamehr | Ying-Jiu Lu | Tzu‐Ying Lin | A.‐P. Tsai | Chih‐Huang Lai
Source: Scientific Reports (article, 2019-02-04)
Field: Materials Science — Materials Chemistry

In-Situ observation of local atomic structure of Al-Cu-Fe quasicrystal formation The phase and local environment, neighbouring atoms and coordination numbers (CN), for an Al-Cu-Fe multilayer were studied during heating (to 800 °C) and cooling (to room temperature) processes using in-situ X-Ray diffraction (XRD) and in-situ X-ray absorption spectroscopy (XAS) techniques to investigate the formation of Al-Cu-Fe quasicrystals (QCs). In-situ XRD clarified the transition of the ω-Al<sub>7</sub>Cu<sub>2</sub>Fe phase to a liquid state at the high temperature which transformed into the QC phase during cooling. The in-situ XAS showed a relatively small shift in distance between Cu-Al and Fe-Al during the phase evolution from RT to 700 °C. The distance between Cu-Cu, however, showed a significant increase from ω-phase at 700 °C to the liquid state at 800 °C, and this distance was maintained after QC formation. Furthermore, the CN of Fe-Al was changed to N = 9 during cooling. Through our observations of changes in CN, atomic distances and the atomic environment, we propose the local structural ordering of the quasicrystalline phase originated from a liquid state via ω-phase. In this study, we give a clear picture of the atomic environment from the crystalline to the quasicrystalline phase during the phase transitions, which provides a better understanding of the synthesis of functional QC nanomaterials. Quasicrystal ; X-ray absorption spectroscopy ; In situ ; Phase (matter) ; Materials science ; Diffraction ; Phase transition ; Spectroscopy ; Crystallography ; Chemical state ; Absorption spectroscopy ; Absorption (acoustics) ; Analytical Chemistry (journal) ; Chemistry ; X-ray photoelectron spectroscopy ; Condensed matter physics ; Physics ; Optics ; Nuclear magnetic resonance Quasicrystal Structures and Properties ; Mineralogy and Gemology Studies ; Microstructure and mechanical properties
Authors: Quentin Huaulmé | Sadiara Fall | Patrick Lévêque | Gilles Ulrich | Nicolas Leclerc
Source: Chemistry - A European Journal (article, 2019-03-19)
Field: Materials Science — Materials Chemistry

Pairing of α‐Fused BODIPY: Towards Panchromatic n‐Type Semiconducting Materials A chemical strategy to efficiently perform the dimerization of α-fused boron-dipyrromethene (BODIPY) is reported. The straightforward synthesis of one of these dimers is described and its properties have been investigated through UV/Vis spectroscopy, cyclic voltammetry, differential scanning calorimetry, and charge-carrier mobility measurements by using organic field-effect transistors and space-charge-limited current diodes. The results allow a chemical strategy to decrease the tendency of α-fused BODIPY to crystallize, to increase its light-harvesting properties, and to promote isotropic charge carriers transport. Moreover, the disclosed approach is also a way to maintain the deep LUMO level of α-fused BODIPY; thus making this class of materials highly desirable for optoelectronic applications. BODIPY ; Panchromatic film ; Materials science ; Cyclic voltammetry ; HOMO/LUMO ; Diode ; Charge carrier ; Electron mobility ; Optoelectronics ; Photochemistry ; Chemistry ; Molecule ; Organic chemistry ; Physical chemistry ; Physics ; Optics ; Electrode ; Fluorescence ; Electrochemistry Luminescence and Fluorescent Materials ; Conducting polymers and applications ; Organic Electronics and Photovoltaics
Authors: Kim Bini | Petri Murto | Sait Elmas | Mats R. Andersson | Ergang Wang
Source: Polymer Chemistry (article, 2019-01-01)
Field: Materials Science — Polymers and Plastics

Broad spectrum absorption and low-voltage electrochromic operation from indacenodithieno[3,2-<i>b</i>]thiophene-based copolymers The design and application of IDTT-based conjugated polymers for red-to-transparent and black-to-transparent electrochromic switching at low voltages are reported. Electrochromism ; Thiophene ; Copolymer ; Electrochromic devices ; Materials science ; Conjugated system ; Polymer ; Voltage ; Optoelectronics ; Absorption (acoustics) ; Absorption spectroscopy ; Photochemistry ; Polymer chemistry ; Chemistry ; Optics ; Electrode ; Organic chemistry ; Physical chemistry ; Electrical engineering ; Physics Conducting polymers and applications ; Transition Metal Oxide Nanomaterials ; Organic Electronics and Photovoltaics