jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Sven Warfsmann | Dereje H. Taffa | Michael Wark
Source: Journal of Photochemistry and Photobiology A Chemistry (article, 2018-09-29)
Field: Materials Science — Materials Chemistry

Reprint of “Photoelectrocatalytic behavior of electrodeposited zinc ferrite films with varying Zn:Fe ratio” X-ray photoelectron spectroscopy ; Raman spectroscopy ; Zinc ; Materials science ; Stoichiometry ; Ferrite (magnet) ; Photocurrent ; Triethanolamine ; Zinc ferrite ; Metal ; Transmission electron microscopy ; Inorganic chemistry ; Analytical Chemistry (journal) ; Chemical engineering ; Chemistry ; Metallurgy ; Nanotechnology Copper-based nanomaterials and applications ; Iron oxide chemistry and applications ; Magnetic Properties and Synthesis of Ferrites
Authors: G.D. Fura | Yong Long | Jun Yan | Wei Chen | Chang Gen Lin | Yu Song
Source: Acta Crystallographica Section C Structural Chemistry (article, 2018-10-16)
Field: Materials Science — Materials Chemistry

Synthesis, structural characterization and fluorescence enhancement of chromophore-modified polyoxometalates Intramolecular charge transfers between π-conjugated molecules and polyoxometalate (POM) clusters have been observed in donor-acceptor systems based on organic donors and inorganic POM acceptors, which unfortunately results in a general quenching of the chromophore luminescence. The development of POM-chromophore dyads that are capable of tackling the quenching process and enhancing the fluorescence intensity of such systems remains a highly challenging area of study. A family of organic-inorganic polyoxometalate <!?tlsb=-0.2pt>hybrids, {[(n-C<sub>4</sub>H<sub>9</sub>)<sub>4</sub>N]<sub>3</sub>[(MnMo<sub>6</sub>O<sub>24</sub>){(CH<sub>2</sub>)<sub>3</sub>CR}<sub>2</sub>]} [1, R = -NHCH<sub>2</sub>C<sub>14</sub>H<sub>9</sub>, namely (anthracen-9-ylmethyl)amino; 2, R = -NHCH<sub>2</sub>C<sub>13</sub>H<sub>9</sub>, (9H-fluoren-2-ylmethyl)amino; 3, R = -NHCH<sub>2</sub>C<sub>10</sub>H<sub>7</sub>, (naphthalen-2-ylmethyl)amino; 4, R = -NHCH<sub>2</sub>C<sub>16</sub>H<sub>9</sub>, (pyren-2-ylmethyl)amino], were synthesized by covalently tethering π-conjugated molecules onto an Anderson cluster. The resulting POM-chromophore dyads were fully characterized by various spectroscopic techniques, single-crystal X-ray diffraction analysis and ESI-MS. The fluorescence features of these dyads were studied in detail to verify a dramatic emission enhancement that can be achieved by fine-tuning the microenvironment in solution and suppressing the intrinsic photo-induced electron-transfer process. Chromophore ; Characterization (materials science) ; Fluorescence ; Chemistry ; Materials science ; Nanotechnology ; Photochemistry ; Optics ; Physics Polyoxometalates: Synthesis and Applications ; Metal-Organic Frameworks: Synthesis and Applications ; Chemical Synthesis and Reactions
Authors: S.C. Penner | Maryam Kalvandi | J.S. Ritch
Source: Acta Crystallographica Section E Crystallographic Communications (article, 2018-08-21)
Field: Chemistry — Physical and Theoretical Chemistry

A structural study of 2,4-dimethylaniline derivatives Crystallographic studies of nitro-gen-containing small mol-ecules aid in the elucidation of their structure-activity relationships and modes of aggregation. In this study, two previously synthesized mol-ecules are crystallographically characterized for the first time. Reaction of 2,4-di-methyl-aniline with <i>N</i>-bromo-succinimide affords the <i>ortho</i>-brominated derivative 2-bromo-4,6-di-methyl-aniline (<b>1</b>; C<sub>8</sub>H<sub>10</sub>BrN), which sublimates <i>in vacuo</i> to afford crystals featuring hydrogen-bonded chains as well as Type I halogen-halogen inter-actions. Conversely, alkyl-ation of two equivalents of 2,4-di-methyl-aniline with 1,2-di-bromo-ethane affords a separable mixture of <i>N</i>,<i>N</i>'-bis-(2,4-di-methyl-phen-yl)piperazine (<b>2</b>; C<sub>20</sub>H<sub>26</sub>N<sub>2</sub>), which was crystallographically characterized, as well as <i>N</i>,<i>N</i>'-bis-(2,4-di-methyl-phen-yl)ethyl-enedi-amine (<b>3</b>). Aniline ; Chemistry ; Halogen ; Medicinal chemistry ; Amine gas treating ; Derivative (finance) ; Piperazine ; Dimethylaniline ; Cocrystal ; Hydrogen bond ; Alkyl ; Stereochemistry ; Organic chemistry ; Molecule Crystallography and molecular interactions ; Structural and Chemical Analysis of Organic and Inorganic Compounds ; Crystal structures of chemical compounds
Authors: Tülay A. Ateşin | Abdurrahman Ç. Ateşin | Oscar M. Rodríguez | Diego Rivera | Lohany Y. Garcia
Source: Computational and Theoretical Chemistry (article, 2018-07-20)
Field: Chemistry — Organic Chemistry

Conformational analysis of a TADDOL-based phosphoramidite P,N ligand in a palladium(II) η3-π-allyl complex Conformational isomerism ; Chemistry ; Palladium ; Crystallography ; Ring (chemistry) ; Allylic rearrangement ; Ligand (biochemistry) ; Stereochemistry ; Intramolecular force ; Molecule ; Catalysis ; Organic chemistry Organometallic Complex Synthesis and Catalysis ; Asymmetric Hydrogenation and Catalysis ; Coordination Chemistry and Organometallics
Authors: Dylan J. Sures | G. P. Nagabhushana | Alexandra Navrotsky | May Nyman
Source: Preprints.org (preprint, 2018-09-06)
Field: Materials Science — Materials Chemistry

Thermochemical Measurements of Alkali Cation Association to Hexatantalate Ion association is an important process in aqueous dissolution, precipitation, and crystallization of ionic inorganic, organic, and biological materials. Polyoxometalates (POMs) are good model compounds for understanding the complex relationships between lattice energy, ion-pairing in solution, and salt solubility. Here we perform calorimetric measurements to elucidate trends in cluster stability, lattice energy, and ion-pairing behavior studies of simple hexatantalate salts in neat water, parent hydroxide solutions, and molybdate melts, extending previous studies on the isostructural hexaniobates. High temperature calorimetry of alkali salts of hexatantalate reveals that the enthalpies of formation from oxides of the K, Rb, and Cs salts are more similar to each other than they are for their niobate analogues and that the tantalate cluster is energetically less stable than hexaniobate. Aqueous dissolution calorimetry reveals that the cesium salt of hexatantalate has a similar concentration dependence on its dissolution enthalpy to that of hexaniobate. However, unlike rubidium hexaniobate, rubidium hexatantalate also exhibits increased concentration dependence, indicating that hextantalate can undergo increased ion-pairing with alkali salts other than cesium, despite the dilute environments studied. Dissolution enthalpies of POM salts in the parent alkali hydroxides shows that protonation of clusters stabilizes lattices even more than the strongly associating heavy alkalis do. Additionally, neither weak nor strong lattice ion associations necessarily correlates with respectively high or low aqueous solubility. These studies illuminate the importance of considering ion-pairing among the interrelated processes in the aqueous dissolution of ionic salts, that can be extended to serving as a model of cation association to metal oxide surfaces. Alkali metal ; Chemistry ; Dissolution ; Inorganic chemistry ; Aqueous solution ; Rubidium ; Lattice energy ; Solubility ; Ionic bonding ; Salt (chemistry) ; Protonation ; Enthalpy ; Ion ; Physical chemistry ; Crystallography ; Crystal structure ; Potassium ; Thermodynamics ; Organic chemistry Polyoxometalates: Synthesis and Applications
Authors: Ge Song | Laura Bovo | Lui R. Terry | Omar Gómez Rojas | Simon R. Hall
Source: CrystEngComm (article, 2018-01-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Increase of Cr solubility in cubic Sr<sub>2</sub>Fe<sub>x</sub>Cr<sub>2−x</sub>O<sub>6−y</sub> unit cell using sol–gel assisted synthesis and characterizations of Sr<sub>2</sub>FeCrO<sub>6−y</sub> phase A homogeneous, non-selective chelating system using EDTA–chitosan was created to produce a cubic phase perovskite material Sr<sub>2</sub>FeCrO<sub>6−y</sub>. Solubility ; Materials science ; Crystallography ; Chemistry ; Physical chemistry Magnetic and transport properties of perovskites and related materials ; Multiferroics and related materials ; Advanced Condensed Matter Physics
Authors: Calbi Gunder | Pijiush K Dhara | Uttam Manna | Mahua Biswas
Source: Nanotechnology (article, 2018-05-30)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Block-copolymer assisted fabrication of anisotropic plasmonic nanostructures The anisotropic nanostructures of noble metals are of great interest for plasmonic applications, due to the possibility of tuning the localized surface plasmon resonance (LSPR) across the UV-visible-near infrared (UV-vis-NIR) without sacrificing the linewidth, as well as achieving larger local field enhancement. Here, we report a simple and promising fabrication method of anisotropic gold nanostructures film using polystyrene-b-poly(2vinylpyridine) (PS-b-P2VP) block copolymers (BCPs) as a template. In this approach, PS-b-P2VP spherical micelles were first synthesized as a template, followed by selective deposition of an Au precursor inside the P2VP core of the micelles, using an ethanol solution of Au salt. Subsequently, heat treatment of the precursor deposited BCP films followed by the removal of the BCP template produced anisotropic gold nanostructures of various shapes, such as octahedron, decahedron, tetrahedron, triangles, and triangular prism. A temperature and time dependent study during heat treatment shows the formation of clusters at a higher temperature. Furthermore, measurements of the ensemble extinction spectra of the anisotropic Au nanoparticle films showed two broad distinct LSPR peaks; one in the visible range (∼660 nm), and the other in the NIR range (∼875 nm). The electrodynamic simulation showed that octahedron and decahedron nanoparticles are responsible for the LSPR response in the visible; whereas the triangular shapes are responsible for the LSPR response in the NIR. Our work is expected to open up a new direction for the synthesis of anisotropic nanostructures of noble metals, that can be utilized to tune the LSPR response across the UV-vis-NIR range, using a simple BCP template-based method. Materials science ; Nanostructure ; Nanoclusters ; Plasmon ; Nanodot ; Surface plasmon resonance ; Nanoparticle ; Nanotechnology ; Visible spectrum ; Noble metal ; Colloidal gold ; Anisotropy ; Optoelectronics ; Optics ; Metal Gold and Silver Nanoparticles Synthesis and Applications ; Nanoparticle-Based Drug Delivery ; Block Copolymer Self-Assembly
Authors: Milica Matijević | Iva Popović | Milutin Stepić | Maja D. Nešić | Marija Radoičić | Maja Stanković | Zoran Šaponjić | Marijana Petković
Source: VinaR (Institute of Nuclear Sciences "Vinča") (article, 2018-10-24)
Field: Materials Science — Materials Chemistry

Inorganic Nanoparticles In Biology: Drug Carriers And Auxiliary Tools In Bioimaging And Bioanalytics Among various nano-scaled materials composed from a spectrum of chemical compounds, inorganic nanoparticles are very attractive due to their physico-chemical properties, as well as their availability, simplicity, possibility of modifications, stability and biocompatibility. They are, on the one hand, an useful tool in advanced analytical chemistry, in particular for studying of biologically-relevant processes, but also important as functional parts of the systems designed for controlled and targeted delivery of medicaments for treatment of a variety of diseases and for imaging. So far, thousands of compounds and systems have been developed for the above-mentioned purposes, but there are only a few reviews dealing with these topics. The aim of this review is, thus, to summarize recent applications of nano-structured inorganic materials in the field of drug delivery, bioimaging and bioanalytics, and to give a prospective from the standpoint of biology-related applications. Nanotechnology ; Nanoparticle ; Drug ; Drug carrier ; Drug delivery ; Materials science ; Biology ; Pharmacology Advanced Nanomaterials in Catalysis ; Nanoparticle-Based Drug Delivery ; Computational Drug Discovery Methods
Authors: Durgesh Nandkishor Boob | Santosh Dattu Navale | Manoj Mahale | Machindra Jayram Chavan
Source: American Journal of PharmTech Research (review, 2018-06-08)
Field: Chemistry — Spectroscopy

A Review on Impurities Profiling in Pharmaceutical Analysis In the pharmaceutical industry an impurity is considered, defined the any other organic material besides the drug substance or pharmaceutical ingredients. The impurity may be formed during the formulation or upon aging of two APIs in medicines. The highly sophisticated instrumentation, such as mass spectra meters attached to the gas chromatography or HPLC in various matrices. GC is the most useful technique for identification of residual solvent. The advent of hyphenated technique has revolution any impurity profiling, by not only separation but structural identification of impurities as well among all techniques. The most exploited techniques for impurities profiling of drug are LC-MS-MS, LC-NMR, LC-NMR-MS, GC-MS AND LC-MS. Profiling (computer programming) ; Computer science Analytical Chemistry and Chromatography ; Computational Drug Discovery Methods ; Analytical Methods in Pharmaceuticals
Authors: Masahiro Miura | Koji Hirano | Chiaki Yamamoto | Kazutaka Takamatsu
Source: Heterocycles (article, 2018-01-01)
Field: Chemistry — Organic Chemistry

Oxidative Rearrangement of Benzylamines to 4H-3,1-Benzoxazines via Cu/Mn-Promoted Intramolecular C–H Amination/Electrocyclic Reaction Cascade We have developed a copper/manganese-mediated oxidative rearrangement of benzylamines to 4H-3,1-benzoxazines of potent interest in medicinal applications. The reaction proceeds uniquely through the initial copper/manganese-promoted intramolecular C-H amination giving benzazetidine intermediates and subsequent 4 electrocyclic ring opening/6 electrocyclic ring closing cascade. The key to success is the introduction of picolinamide-based N,N-bidentate directing group. The obtained benzoxazines can also be readily hydrolyzed to the corresponding 2-aminobenzyl alcohols, thus indicating that the overall transformations is regarded as the ortho-aminative rearrangement of benzylamines to benzylic alcohols. Chemistry ; Intramolecular force ; Amination ; Ring (chemistry) ; Medicinal chemistry ; Cascade reaction ; Manganese ; Electrocyclic reaction ; Oxidative phosphorylation ; Denticity ; Hydrolysis ; Stereochemistry ; Organic chemistry ; Catalysis ; Metal Catalytic C–H Functionalization Methods ; Synthesis and Catalytic Reactions ; Phenothiazines and Benzothiazines Synthesis and Activities
Authors: Anders Strand | Lari Vähäsalo | Elias Retulainen | Anna Sundberg
Source: Cellulose (article, 2018-11-21)
Field: Materials Science — Biomaterials

Analysis of cellulose nanocrystals (CNCs) with flow cytometry Cellulose nanocrystals (CNCs) were prepared from kraft pulps of eucalyptus, birch, and softwood. The different kraft pulps were hydrolyzed using strong sulfuric acid in order to obtain colloidally stable CNCs. The CNCs were studied using flow cytometry (FCM). The light scattering properties of the CNCs in side direction and forward direction were documented. The use of a selective staining agent in combination with FCM analysis enabled detection of the hydrophobic particle populations within the CNC suspensions. The hydrophobic particles were seen clearly in the CNCs from the eucalyptus and birch kraft pulps, but not in the CNCs from softwood pulp. These particles were shown to be linked with the content of lipophilic extractives, especially sterols, present in the kraft pulps. From this fact, it was concluded that FCM analyses offer useful information about the properties of CNCs in suspension. It was also concluded that the content of lipophilic extractives in different raw materials should be determined and considered prior to CNC production. Pre-extraction steps might be needed in order to produce high-quality CNCs from various raw materials, even from kraft pulps. Kraft process ; Kraft paper ; Cellulose ; Softwood ; Pulp (tooth) ; Materials science ; Raw material ; Hydrolysis ; Sulfuric acid ; Pulp and paper industry ; Chemical engineering ; Nanocellulose ; Acid hydrolysis ; Chemistry ; Chromatography ; Composite material ; Organic chemistry Advanced Cellulose Research Studies ; Polysaccharides and Plant Cell Walls ; Lignin and Wood Chemistry
Authors: Lionel Vidaud
Source: Journal of Analytical Science & Technology (article, 2018-06-21)
Field: Chemistry — Organic Chemistry

Mat-CHN software for drug substance titrations in discovery and development Elemental Analysis (microanalysis) is a reference method widely used to make assessments of thequality of chemical or biochemical substances. Using very small quantities of substance and no methoddevelopment, this analytical technique delivers absolute assays. Compared to other methods needing larger samplequantities and most of the time reference standards, the Elemental Analysis is the preferred technique of scientists. One of the difficulties with this method is the definition of the theoretical elemental composition when several complementary assays values, generally delivered in w/w percentages (e.g., water content by Karl Fischer method), instead of mole numbers (as this is the case for NMR determination), must be taken into account. The situation is manageable with only one of this type of additional assay; however, this exercise becomes more complicated when the scientists must integrate two or more assay values. Mat-CHN software was developed specifically to resolve these difficulties, by delivering the individual mole numberof each constituent assayed in the compound analyzed, leading to an accurate comparison of the theoretical and experimental results of centesimal compositions. Apart its large capabilities for simulations, Mat-CHN increases the interest of the Elemental Analysis technique for scientists working in discovery fields or when new molecular entities are promoted to pre-development and development stages, either for absolute titration of their reference standards or for direct titrations of the drug substance itself. The software conducts to simple titration determinations, based on Nitrogen “Kjeldhal” assays and/or molecular weight reports, compared to data of the pure substance. Based on experimental analytical data, Mat-CHN software delivers accurate elemental content determinations and titration of the substance analyzed. These results should be considered also experimental ones, because Mat-CHN resolves the equations without any convergence or external parameters. Titration ; Elemental analysis ; Microanalysis ; Chemistry ; Analytical Chemistry (journal) ; Computer science ; Biochemical engineering ; Chromatography ; Organic chemistry ; Engineering Chemical Thermodynamics and Molecular Structure ; Analytical Chemistry and Chromatography ; thermodynamics and calorimetric analyses
Authors: Prithiviraj Chellamuthu | Frances Tran | Kalinga Pavan T. Silva | Mohamed Y. El‐Naggar | James Q. Boedicker
Source: bioRxiv (Cold Spring Harbor Laboratory) (preprint, 2018-02-15)
Field: Materials Science — Materials Chemistry

Engineering bacteria for biogenic synthesis of chalcogenide nanomaterials Summary Microbes naturally build nanoscale structures, including structures assembled from inorganic materials. Here we combine the natural capabilities of microbes with engineered genetic control circuits to demonstrate the ability to control biological synthesis of chalcogenide nanomaterials in a heterologous host. We transferred reductase genes from both Shewanella sp. ANA-3 and Salmonella enterica serovar Typhimurium into an heterologous host ( Escherichia coli) and examined the mechanisms that regulate the properties of biogenic nanomaterials. Expression of arsenic reductase genes and thiosulfate reductase genes in E. coli resulted in the synthesis of arsenic sulfide nanomaterials. In addition to processing the starting materials via redox enzymes, cellular components also nucleated the formation of arsenic sulfide nanomaterials. The shape of the nanomaterial was influenced by the bacterial culture, with the synthetic E. coli strain producing nanospheres and conditioned media or cultures of wild type Shewanella sp. producing nanofibers. The diameter of these nanofibers also depended on the biological context of synthesis. These results demonstrate the potential for biogenic synthesis of nanomaterials with controlled properties by combining the natural capabilities of wild microbes with the tools from synthetic biology. Nanomaterials ; Escherichia coli ; Synthetic biology ; Context (archaeology) ; Nanotechnology ; Chemistry ; Biology ; Materials science ; Biochemistry ; Gene ; Computational biology Nanoparticles: synthesis and applications ; Advanced Nanomaterials in Catalysis ; Arsenic contamination and mitigation
Authors: Jan Carmeliet | Ming-Yang Chen | Dominique Derome
Source: Healthy, Intelligent and Resilient Buildings and Urban Environments (article, 2018-01-01)
Field: Materials Science — Polymers and Plastics

Sorption hysteresis in wood and its coupling to swelling: a new modelling approach Sorption hysteresis of amorphous cellulose is studied. Cellulose, as a renewable organic biopolymer, is an essential component of various natural composites such as wood. A coupling process between sorption and deformation leads to the hysteresis as observed in sorption and swelling, both experimental and simulated for cellulose and wood in general. Sorption ; Swelling ; Cellulose ; Hysteresis ; Biopolymer ; Materials science ; Composite material ; Amorphous solid ; Coupling (piping) ; Chemical engineering ; Polymer ; Adsorption ; Chemistry ; Organic chemistry Textile materials and evaluations ; Material Properties and Processing
Authors: Aleksandra Ivanoska-Dacikj | Gordana Bogoeva‐Gaceva | Srećko Valić
Source: Contributions Section of Natural Mathematical and Biotechnical Sciences (article, 2018-07-02)
Field: Materials Science — Polymers and Plastics

ELECTRON SPIN RESONANCEON HYBRID NANOCOMPOSITES BASED ON NATURAL RUBBER Electron spin resonance (ESR) was used as a new method to analyze the synergy between two nanofillers dif-ferent by nature, form and rigidity dispersed in natural rubber matrix. Natural rubber (NR) nanocomposites loaded with fixed amount of carbon nanotubes (2 parts per hundred of rubber parts; phr) and various amounts of expanded organically modified montmorillonite (EOMt, 4–20 phr) were investigated. The dependence of the double integral of the resonance spectra on the amount of EOMt present in the natural rubber was established. Its decrease with an in-creaseof the amount of EOMt confirmed the synergy between these two nanofillers. Also DMA temperature sweep measurements were performed and the cluster-cluster aggregation (CCA) model was used to assess the apparent filler networking energy. The obtained results suggest that the presence of the EOMt above a critical amount strengthens the hybrid-filler networking. Natural rubber ; Nanocomposite ; Materials science ; Carbon black ; Composite material ; Montmorillonite ; Electron paramagnetic resonance ; Filler (materials) ; Cluster (spacecraft) ; Vulcanization ; Rigidity (electromagnetism) ; Nuclear magnetic resonance ; Physics ; Computer science Polymer Nanocomposites and Properties ; Conducting polymers and applications ; Porphyrin and Phthalocyanine Chemistry