jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Sarhan Sanaa Tareq | Mohd Izham Saiman | Taufiq-Yap Yun Hin | Abdul Halim Abdullah | Umer Rashid
Source: BULLETIN OF CHEMICAL REACTION ENGINEERING AND CATALYSIS (article, 2018-03-06)
Field: Materials Science — Materials Chemistry

The Impact of Hydrogen Peroxide as An Oxidant for Solvent-free Liquid Phase Oxidation of Benzyl Alcohol using Au-Pd Supported Carbon and Titanium Catalysts The solvent free oxidation of benzyl alcohol was conducted employing Au and Pd supported catalysts, while utilizing hydrogen peroxide 35% (H2O2) as the oxidant, H2O2 is very cheap, mild, and an environment friendly reagent, which produced water as the only by-product. Various proportions of Au-Pd catalysts on carbon and titanium oxide activated as supports were synthesized through the use of sol immobilization catalyst synthesis technique. Characterization of the synthesized catalysts was performed using X-Ray Diffraction (XRD), Brunauer-Emmett-Teller (BET), Field Emission Scanning Electron Microscopy (FESEM), and Transmission Electron Microscopy (TEM). It was found that the synthesized Au-Pd/ activated carbon catalyst was beneficial for the solvent free oxidation of benzyl alcohol after its containing high surface area measuring 871 m2g-1. Analysis of the TEM data and particle dimension revealed smaller and narrower particle size of 1 wt%. Thus, the distribution of Au-Pd/C was attained. Carbon-supported bimetallic catalysts presented a higher conversion compared to catalysts that are supported titanium oxide (TiO2) for for the oxidation reaction of benzyl alcohol. It was determined that this technique was a suitable process for catalyst synthesis with high selectivity, same distribution of the particle size and activations. Catalysis ; Benzyl alcohol ; Hydrogen peroxide ; Bimetallic strip ; Materials science ; Solvent ; Particle size ; Inorganic chemistry ; Titanium ; Alcohol oxidation ; Titanium oxide ; Reagent ; Activated carbon ; Nuclear chemistry ; Chemistry ; Organic chemistry ; Metallurgy Catalytic Processes in Materials Science ; Oxidative Organic Chemistry Reactions ; Catalysis and Oxidation Reactions
Authors: Joel A. Finbloom | Matthew B. Francis
Source: Current Opinion in Chemical Biology (review, 2018-07-21)
Field: Chemistry — Organic Chemistry

Supramolecular strategies for protein immobilization and modification Supramolecular chemistry ; Nanotechnology ; Chemical biology ; Posttranslational modification ; Chemistry ; Combinatorial chemistry ; Covalent bond ; Molecule ; Materials science ; Biochemistry ; Organic chemistry Click Chemistry and Applications ; Chemical Synthesis and Analysis ; Supramolecular Self-Assembly in Materials
Authors: Lulu Teressa Poulsen | Mads Heuckendorff | Henrik H. Jensen
Source: ACS Omega (article, 2018-06-29)
Field: Chemistry — Organic Chemistry

Effect of 2-<i>O</i>-Benzoyl para-Substituents on Glycosylation Rates From a series of competition experiments, we have explored the degree to which various para-substituents (CN, Br, H, OMe, pyrrolidino) of a 2-<i>O</i>-benzoyl functionalized glucosyl donor of the thioglycoside type affect the rate of glycosylation under <i>N</i>-iodosuccinimide/triflic acid activation. As expected, electron-withdrawing groups were found to decrease the rate of glycosylation, whereas electron-donating groups resulted in the opposite outcome, underscoring the influence on the reaction rate exerted by a participating group. On this basis, a Hammett linear free-energy relationship was established (<i>R</i> <sup>2</sup> = 0.979, ρ = 0.6), offering fundamental insight into the magnitude of anchimeric assistance in glycosylation chemistry. Glycosylation ; Chemistry ; Triflic acid ; Competition (biology) ; Polar effect ; Medicinal chemistry ; Stereochemistry ; Organic chemistry ; Catalysis ; Biochemistry Carbohydrate Chemistry and Synthesis ; Glycosylation and Glycoproteins Research ; Enzyme Catalysis and Immobilization
Authors: Konstanze Seidler | Katharina Ehrmann | Patrick Steinbauer | Andreas Rohatschek | Orestis G. Andriotis | Claudia Dworak | Thomas Koch | Helga Bergmeister | Christian Grasl | Heinrich Schima | Philipp J. Thurner | Robert Liska | Stefan Baudis
Source: Journal of Polymer Science Part A Polymer Chemistry (article, 2018-09-09)
Field: Materials Science — Biomaterials

A structural reconsideration: Linear aliphatic or alicyclic hard segments for biodegradable thermoplastic polyurethanes? ABSTRACT Thermoplastic polyurethane elastomers (TPUs) with a biodegradable chain extender and different nonaromatic diisocyanate hard segments were synthesized and tested concerning their thermal, mechanical, and degradation properties and for their processability regarding electrospinning. The design of the TPUs was based on the structural modification of the hard segment using linear aliphatic hexamethylene diisocyanate (HMDI), more rigid alicyclic 4,4′‐methylene bis(cyclohexylisocyanate) (H12MDI), 1,3‐bis(isocyanatomethyl)cyclohexane (BIMC), or isophorone diisocyanate (IPDI). The soft segment consisted of poly(tetrahydrofuran). Bis(2‐hydroxyethyl) terephthalate (BET) was used as chain extender with cleavable ester bonds. Some of the polyurethanes based on alicyclic diisocyanate showed better mechanical performance than the less rigid HMDI‐based TPU. The TPU in vitro degradability was tested for 25 days at elevated temperatures in PBS buffer and indicated a bulk erosion process. Electrospinning experiments were conducted and promising results with respect to further applicability of these materials in vascular tissue engineering were obtained. © 2018 The Authors Journal of Polymer Science Part A: Polymer Chemistry Published by Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56 , 2214–2224 Isophorone diisocyanate ; Hexamethylene diisocyanate ; Materials science ; Polymer chemistry ; Alicyclic compound ; Thermoplastic polyurethane ; Thermoplastic ; Polyurethane ; Elastomer ; Polyester ; Diol ; Polymer ; Chemical engineering ; Polymer science ; Composite material Electrospun Nanofibers in Biomedical Applications ; Polymer composites and self-healing ; biodegradable polymer synthesis and properties
Authors: Randy L. Lawrence | Zak E. Hughes | Vincent J. Cendan | Yang Liu | Chang‐Keun Lim | Paras N. Prasad | Mark T. Swihart | Tiffany R. Walsh | Marc R. Knecht
Source: ACS Applied Materials & Interfaces (article, 2018-09-06)
Field: Materials Science — Biomaterials

Optical Control of Nanoparticle Catalysis Influenced by Photoswitch Positioning in Hybrid Peptide Capping Ligands Here, we present an in-depth analysis of structural factors that modulate peptide-capped nanoparticle catalytic activity via optically driven structural reconfiguration of the biointerface present at the particle surface. Six different sets of peptide-capped Au nanoparticles were prepared, in which an azobenzene photoswitch was incorporated into one of two well-studied peptide sequences with known affinity for Au, each at one of three different positions: the N- or C-terminus or mid-sequence. Changes in the photoswitch isomerization state induce a reversible structural change in the surface-bound peptide, which modulates the catalytic activity of the material. This control of reactivity is attributed to changes in the amount of accessible metallic surface area available to drive the reaction. This research specifically focuses on the effect of the peptide sequence and photoswitch position in the biomolecule, from which potential target systems for on/off reactivity have been identified. Additionally, trends associated with photoswitch position for a peptide sequence (Pd4) have been identified. Integrating the azobenzene at the N-terminus or central region results in nanocatalysts with greater reactivity in the trans and cis conformations, respectively, however, positioning the photoswitch at the C-terminus gives rise to a unique system that is reactive in the trans conformation and partially deactivated in the cis conformation. These results provide a fundamental basis for new directions in nanoparticle catalyst development to control activity in real time, which could have significant implications in the design of catalysts for multistep reactions using a single catalyst. Additionally, such a fine level of interfacial structural control could prove to be important for applications beyond catalysis, including biosensing, photonics, and energy technologies that are highly dependent on particle surface structures. Photoswitch ; Azobenzene ; Peptide ; Materials science ; Reactivity (psychology) ; Isomerization ; Nanoparticle ; Catalysis ; Combinatorial chemistry ; Chemistry ; Nanotechnology ; Photochemistry ; Organic chemistry ; Biochemistry ; Molecule Supramolecular Self-Assembly in Materials ; Photochromic and Fluorescence Chemistry ; Advanced biosensing and bioanalysis techniques
Authors: Madalyn M. Liebum | George J. Hirasaki | Quoc P. Nguyen
Source: Petroleum Science (article, 2018-02-10)
Field: Chemistry — Organic Chemistry

A systematic rheological study of alkyl amine surfactants for fluid mobility control in hydrocarbon reservoirs The basis of this study is to identify the versatility of N,N,N′-trimethyl-N′-tallow-1,3-diaminopropane (DTTM) surfactant in high saline environments. The surfactant was examined with sodium chloride, NaCl, to understand how triggers such as salt, pH, temperature, and surfactant concentration influences the viscoelastic response of the surfactant solution. The DTTM surfactant and salt (NaCl) concentrations used in steady-state shear viscosity analysis range from 0.2 wt% to 2 wt% and 5 wt% to 25 wt%, respectively. Along with DTTM results, three similar chemical structures are investigated to understand how viscosity changes with alterations in tail and head group composition. It was found that DTTM surfactant has the capability of transitioning from a foam-bearing to viscoelastic state at low surfactant concentrations under moderate to high saline conditions. A longer tail length promotes viscoelasticity and shear-thinning behavior. Terminals consisting of hydroxides or ethoxylates have a lower viscosity than that of methyl terminals. A head group consisting of two nitrogen atoms has a higher viscosity than those containing one nitrogen atom. The rheological characterization of DTTM presented in this paper is part of a larger study in determining the capability of this surfactant to foam CO2 for improving mobility control in CO2 enhanced oil recovery in high saline oil formations. Pulmonary surfactant ; Viscoelasticity ; Rheology ; Viscosity ; Chemistry ; Chemical engineering ; Shear thinning ; Alkyl ; Hydrocarbon ; Enhanced oil recovery ; Chromatography ; Materials science ; Organic chemistry ; Composite material ; Biochemistry Surfactants and Colloidal Systems ; Enhanced Oil Recovery Techniques ; Petroleum Processing and Analysis
Authors: Louise Kerins | Sylvester Byrne | Adele Gabba | Paul V. Murphy
Source: The Journal of Organic Chemistry (article, 2018-07-04)
Field: Chemistry — Organic Chemistry

Anomer Preferences for Glucuronic and Galacturonic Acid and Derivatives and Influence of Electron-Withdrawing Substituents Equilibrium anomeric ratios are reported for pyranoses (hemiacetals) of glucuronic and galacturonic acid and their derivatives. These are compared to related gluco- and galactopyranoses and to deoxyfluorogluco- and deoxyfluorogalactopyranoses. An association between axial anomer stability and the sum of <sup>1</sup>H NMR downfield chemical shifts for protons H-3 and H-5 was observed in D<sub>2</sub>O with gluco- and galactopyranoses as reference compounds. When compared to 2-hydroxytetrahydropyran in water, introduction of three OAc substituents and one carboxylic acid substituent leads to an increase in stability of the axial anomer by 0.89-1.05 kcal/mol. This is interpreted as the electron-withdrawing substituents causing a reduction in the steric (gauche) interaction and an increase in favourable Coulombic interaction between CH groups of the pyranose and the anomeric group through substituent deshielding effects. Anomer preferences for galacturonic acid and its derivatives were more sensitive to solvent polarity compared to other pyranoses, and this may be linked to the electrostatic potential and reduced stabilization of the equatorial anomeric OH group due to reduced hydrogen bonding. The latter is more notable in nonpolar chloroform. Analysis of crystal structures combined with molecular dynamics indicated there are conformational distinctions between galacturonic acid and glucuronic acid that could influence properties. Chemistry ; Substituent ; Pyranose ; Anomer ; Steric effects ; Glucuronic acid ; Stereochemistry ; Hydrogen bond ; Anomeric effect ; Medicinal chemistry ; Organic chemistry ; Molecule Carbohydrate Chemistry and Synthesis ; Enzyme Production and Characterization ; Enzyme Catalysis and Immobilization
Authors: Santiago Reinoso | Beñat Artetxe | Juan M. Gutiérrez‐Zorrilla
Source: Acta Crystallographica Section C Structural Chemistry (article, 2018-10-18)
Field: Materials Science — Materials Chemistry

Single-crystal-to-single-crystal transformations triggered by dehydration in polyoxometalate-based compounds Single-crystal-to-single-crystal transformations are solid-state phase transitions between different crystalline states in which the crystal integrity and the long-range structural order are retained through the whole transformation process. Such a phenomenon constitutes the structural response that some compounds afford when being exposed to a given external stimulus (temperature, pressure, light, etc.) and, therefore, its study has become a relevant focus of interest within crystal engineering because it allows for monitoring how certain properties (colour, magnetism, luminescence, porosity) of the stimuli-responsive material are modified as the structure evolves into the activated form. A range of organic, inorganic and hybrid systems have been found to undergo such phase transitions, but these examples only include a small number of compounds that incorporate polyoxometalate anions, among which the removal of guest solvent molecules (dehydration) stands out as the most common external stimulus able to induce the occurrence of a single-crystal-to-single-crystal transformation. This feature article compiles the examples of dehydration-triggered single-crystal-to-single-crystal transformation studies that have been reported to date for polyoxometalate-based compounds and reviews some of their most relevant structural aspects. Polyoxometalate ; Single crystal ; Crystal (programming language) ; Materials science ; Crystallography ; Dehydration ; Crystal structure ; Chemical physics ; Luminescence ; Crystal engineering ; Solvent ; Chemistry ; Nanotechnology ; Organic chemistry ; Optoelectronics ; Supramolecular chemistry ; Computer science ; Catalysis Polyoxometalates: Synthesis and Applications ; Metal-Organic Frameworks: Synthesis and Applications ; Supramolecular Chemistry and Complexes
Authors: Mohammad A. Alnajjar | Juergen Bartelmess | Robert Hein | Pichandi Ashokkumar | Mohamed Nilam | Werner M. Nau | Knut Rurack | Andreas Hennig
Source: Beilstein Journal of Organic Chemistry (article, 2018-07-30)
Field: Materials Science — Materials Chemistry

Rational design of boron-dipyrromethene (BODIPY) reporter dyes for cucurbit[7]uril We introduce herein boron-dipyrromethene (BODIPY) dyes as a new class of fluorophores for the design of reporter dyes for supramolecular host-guest complex formation with cucurbit[7]uril (CB7). The BODIPYs contain a protonatable aniline nitrogen in the <i>meso</i>-position of the BODIPY chromophore, which was functionalized with known binding motifs for CB7. The unprotonated dyes show low fluorescence due to photoinduced electron transfer (PET), whereas the protonated dyes are highly fluorescent. Encapsulation of the binding motif inside CB7 positions the aniline nitrogen at the carbonyl rim of CB7, which affects the p<i>K</i><sub>a</sub> value, and leads to a host-induced protonation and thus to a fluorescence increase. The possibility to tune binding affinities and p<i>K</i><sub>a</sub> values is demonstrated and it is shown that, in combination with the beneficial photophysical properties of BODIPYs, several new applications of host-dye reporter pairs can be implemented. This includes indicator displacement assays with favourable absorption and emission wavelengths in the visible spectral region, fluorescence correlation spectroscopy, and noncovalent surface functionalization with fluorophores. Chemistry ; BODIPY ; Chromophore ; Protonation ; Fluorescence ; Photochemistry ; Supramolecular chemistry ; Surface modification ; Photoinduced electron transfer ; Combinatorial chemistry ; Electron transfer ; Molecule ; Organic chemistry ; Physical chemistry Luminescence and Fluorescent Materials ; Molecular Sensors and Ion Detection ; Supramolecular Chemistry and Complexes
Authors: Stefan Knoppe | Hannu Häkkinen | Thierry Verbiest | Koen Clays
Source: The Journal of Physical Chemistry C (article, 2018-01-30)
Field: Materials Science — Materials Chemistry

Role of Donor and Acceptor Substituents on the Nonlinear Optical Properties of Gold Nanoclusters In recent years, a large number of monolayer-protected clusters (MPCs) have been studied by means of single crystal structure characterization. A central aspect of research on MPCs is the correlation of their interesting optical properties with structural features and the formulation of a theoretical framework that allows interpretation of their unique properties. For this, superatom and jellium models have been proven successful. Little attention, however, has been paid to the influence of the protecting ligands. Here, we investigate the effect of changes in [Au25(SR)18-x(SR′)x]−, where SR′ represents a para-substituted thiophenolate derivative (SPh-4-X). We computed the first hyperpolarizabilities, screening a broad range of substituents X. For [Au25(SR)17(SR′)1]− clusters, significant first hyperpolarizabilities were calculated, spanning 2 orders of magnitude depending on X. A strong dependence on the electron-donating/withdrawing properties of the substituent was found for para-substituted thiophenol ligands. Protonation of amine substituents leads to a change from donor to acceptor substitution, leading to a record setting contrast for nonlinear optical proton sensing. Furthermore, “push/pull” systems were considered where both an acceptor and a donor ligand were positioned at opposite ends of the cluster. This induces significant increase of the first hyperpolarizability through charge transfer. Overall, our results indicate that the right choice of ligand can significantly impact the (nonlinear) optical properties of MPCs. This adds a new component to the cluster chemist’s toolbox. Nanoclusters ; Acceptor ; Nonlinear optical ; Materials science ; Nonlinear system ; Photochemistry ; Nonlinear optics ; Nanotechnology ; Chemistry ; Chemical physics ; Condensed matter physics ; Physics ; Quantum mechanics Nanocluster Synthesis and Applications ; Gold and Silver Nanoparticles Synthesis and Applications ; Advanced Nanomaterials in Catalysis
Authors: Ignacio A. Jessop | F. R. Díaz | Claudio A. Terraza | Alain Tundidor‐Camba | Ángel Leiva | L. Cattin | J.C. Bérnède
Source: Polymers (article, 2018-05-21)
Field: Materials Science — Polymers and Plastics

PANI Branches onto Donor-Acceptor Copolymers: Synthesis, Characterization and Electroluminescent Properties of New 2D-Materials A new series of two-dimensional statistical conjugated polymers based on aniline and 9,9-dihexylfluorene as donor units and benzo- or naphtho-quinoxaline/thiadiazole derivatives as acceptor moieties, possessing PANI segments as side chains, were designed and synthesized. To investigate the effects of the perpendicular PANI branches on the properties of the main chain, the optical, electrochemical, morphological and electroluminescence properties were studied. The 2D materials tend to possess lower molecular weights and to absorb and to emit light red-shifted compared to the trunk 1D-polymers, in the yellow-red region of the visible spectrum. The 1D- and 2D-conjugated polymers present optical band gaps ranging from 2.15⁻2.55 eV, HOMO energy levels between -5.37 and -5.60 eV and LUMO energy levels between -3.02 and -3.29 eV. OLED devices based on these copolymers were fabricated. Although the performances were far from optimal due to the high turn-on voltages for which electroluminescence phenomena occur, a maximum luminescence of 55,100 cd/m² together with a current density of 65 mA/cm² at 18.5 V were recorded for a 2D-copolymer, <b>PAFC6TBQ-PANI</b>. Electroluminescence ; Materials science ; Copolymer ; HOMO/LUMO ; Conjugated system ; Polymer ; Luminescence ; Acceptor ; Side chain ; Photochemistry ; Band gap ; Polymer chemistry ; Optoelectronics ; Nanotechnology ; Molecule ; Organic chemistry ; Chemistry ; Composite material Conducting polymers and applications ; Organic Electronics and Photovoltaics ; Perovskite Materials and Applications
Authors: Xi Chen | Muthukumaran Venkatachalapathy | Leif Dehmelt | Yao‐Wen Wu
Source: Angewandte Chemie International Edition (article, 2018-07-26)
Field: Materials Science — Materials Chemistry

Multidirectional Activity Control of Cellular Processes by a Versatile Chemo‐optogenetic Approach The spatiotemporal dynamics of proteins or organelles plays a vital role in controlling diverse cellular processes. However, acute control of activity at distinct locations within a cell is challenging. A versatile multidirectional activity control (MAC) approach is presented, which employs a photoactivatable system that may be dimerized upon chemical inducement. The system comprises second-generation SLF*-TMP (S*T) and photocaged NvocTMP-Cl dimerizers; where, SLF*-TMP features a synthetic ligand of the FKBP(F36V) binding protein, Nvoc is a caging group, and TMP is the antibiotic trimethoprim. Two MAC strategies are demonstrated to spatiotemporally control cellular signaling and intracellular cargo transport. The novel platform enables tunable, reversible, and rapid control of activity at multiple compartments in living cells. Optogenetics ; FKBP ; Chemistry ; Organelle ; Intracellular ; Synthetic biology ; Cytoplasm ; Biophysics ; Cell biology ; Computational biology ; Biology ; Biochemistry ; Neuroscience Photochromic and Fluorescence Chemistry ; Photoreceptor and optogenetics research ; Light effects on plants
Authors: Dolores Pérez‐Marín | Luis Calero | Tom Fearn | Irina Torres | Ana Garrido‐Varo | María‐Teresa Sánchez
Source: Postharvest Biology and Technology (article, 2018-09-20)
Field: Chemistry — Analytical Chemistry

A system using in situ NIRS sensors for the detection of product failing to meet quality standards and the prediction of optimal postharvest shelf-life in the case of oranges kept in cold storage Postharvest ; Cold storage ; Shelf life ; Control chart ; Environmental science ; Quality (philosophy) ; Citrus fruit ; Mathematics ; Computer science ; Horticulture ; Chemistry ; Food science ; Biology ; Physics Spectroscopy and Chemometric Analyses ; Pesticide Residue Analysis and Safety ; Advanced Chemical Sensor Technologies
Authors: Alper KOÇAK | Bekir Karasu
Source: El-Cezeri Fen ve Mühendislik Dergisi (article, 2018-01-31)
Field: Materials Science — Materials Chemistry

General Evaluations of Nanoparticles Nanotanecikler aslında uzun yıllardır hayatımızda yeralan nanoteknolojinin giderek gelişmesiyle yaşam döngüsünde büyük bir yer edinmeye başlamıştır. Teknolojideki son dönem çalışma ve gelişmeler kullanımlarının gelecekte daha da artacağını göstermektedir. Biyoloji, tıp, mühendislik, optik gibi birçok alandaki geniş kullanımlarının yanı sıra insanlara ve ekosisteme verdiği zararlarda büyük tartışma konusu olmuştur. Bu derleme yazısında nanotanecikler, kullanım alanları, zararları ve zararlarını önleyici yöntemler ele alınmaktadır. Physics ; Combinatorics ; Mathematics Nanoparticles: synthesis and applications ; Nanotechnology research and applications ; Gold and Silver Nanoparticles Synthesis and Applications