jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Jesse G. Park | Brianna Collins | Lucy E. Darago | Tomče Runčevski | Michael L. Aubrey | Henry Z. H. Jiang | E. A. Velásquez | Mark Green | Jason D. Goodpaster | Jeffrey R. Long
Source: ChemRxiv (preprint, 2020-05-28)
Field: Chemistry — Inorganic Chemistry

Magnetic Ordering via Itinerant Ferromagnetism in a Metal-Organic Framework Materials that combine magnetic order with other desirable physical attributes offer to revolutionize our energy landscape. Indeed, such materials could find transformative applications in spintronics, quantum sensing, low-density magnets, and gas separations. As a result, efforts to design multifunctional magnetic materials have recently moved beyond traditional solid-state materials to metal–organic solids. Among these, metal–organic frameworks in particular bear structures that offer intrinsic porosity, vast chemical and structural programmability, and tunability of electronic properties. Nevertheless, magnetic order within metal–organic frameworks has generally been limited to low temperatures, owing largely to challenges in creating strong magnetic exchange in extended metal–organic solids. Here, we employ the phenomenon of itinerant ferromagnetism to realize magnetic ordering at TC = 225 K in a mixed-valence chromium(II/III) triazolate compound, representing the highest ferromagnetic ordering temperature yet observed in a metal–organic framework. The itinerant ferromagnetism is shown to proceed via a double-exchange mechanism, the first such observation in any metal–organic material. Critically, this mechanism results in variable-temperature conductivity with barrierless charge transport below TC and a large negative magnetoresistance of 23% at 5 K. These observations suggest applications for double-exchange-based coordination solids in the emergent fields of magnetoelectrics and spintronics. Taken together, the insights gleaned from these results are expected to provide a blueprint for the design and synthesis of porous materials with synergistic high-temperature magnetic and charge transport properties. Ferromagnetism ; Spintronics ; Condensed matter physics ; Materials science ; Magnetoresistance ; Metal-organic framework ; Colossal magnetoresistance ; Magnetism ; Valence (chemistry) ; Nanotechnology ; Chemical physics ; Magnetic field ; Chemistry ; Adsorption ; Physics ; Physical chemistry Metal-Organic Frameworks: Synthesis and Applications ; Magnetism in coordination complexes ; Machine Learning in Materials Science
Authors: Zeynel DOĞRUYOL
Source: Middle East Journal of Science (article, 2020-12-30)
Field: Materials Science — Polymers and Plastics

PROTECTIVE BEHAVIOR AGAINST CORROSION OF POLY(N-METHYLANILINE) COATINGS ELECTROSYNTHESIZED ON STAINLESS STEEL SURFACE FROM SULFURIC ACID CONTAINING MONOMER SOLUTION showed that the electroactive PNMA coating can be used as a protective coating against rust for stainless steel. It was demonstrated that Nmethylaniline aniline and pyrrole with an aqueous solution of H2SO4 as the electrolyte can also show positive copolymers and various coatings. Sulfuric acid ; Cyclic voltammetry ; Aqueous solution ; Corrosion ; Monomer ; Materials science ; Polarization (electrochemistry) ; Electrode ; Polymer ; Anode ; Constant current ; Inorganic chemistry ; Electrochemistry ; Voltammetry ; Metallurgy ; Chemistry ; Composite material ; Current (fluid) ; Organic chemistry Conducting polymers and applications ; Corrosion Behavior and Inhibition ; Electrochemical Analysis and Applications
Authors: Tessali Xiaozhu Morrison
Source: DigitalCommons (California Polytechnic State University) (article, 2020-01-01)
Field: Chemistry — Organic Chemistry

Synthesis and Characterization of Double Network Hydrogels Containing Norbornene-Modified Carboxymethyl Cellulose and Cellulose Nanofibrils Double network hydrogels were synthesized using two cellulose derivatives, carboxymethyl cellulose (CMC) and cellulose nanofibrils (CNF). CMC was functionalized to incorporate norbornene groups via amide linkages onto its backbone. These norbornene groups were later crosslinked using dithiol crosslinkers during hydrogel synthesis. CNF was also incorporated into these hydrogels via physical entrapment within the networks. In the final steps, UV radical initiators and irradiation were also used to form hydrogels. To better understand the structures and functions of these hydrogels, key properties such as swelling, moduli, and degradation were explored. Through this research, it was discovered that a critical number of effective crosslinks was required to form hydrogels. This revealed that certain hydrogel formulations were not viable. The addition of CNF produced hydrogels containing higher moduli and slower degradation rates. As the percentage of CNF varied, so did its function within the double networks. At lower percentages, CNF played a reinforcing role, while at higher percentages, interpenetrating networks (IPNs) were created. Ultimately, a high degree of control over hydrogel moduli and CNF composition was achieved. Carboxymethyl cellulose ; Cellulose ; Self-healing hydrogels ; Norbornene ; Characterization (materials science) ; Polymer chemistry ; Materials science ; Chemistry ; Chemical engineering ; Polymer science ; Polymerization ; Nanotechnology ; Organic chemistry ; Polymer ; Sodium Nanomaterials for catalytic reactions
Authors: Jesse G. Park | Brianna Collins | Lucy E. Darago | Tomče Runčevski | Michael Aubrey | Henry Z. H. Jiang | E. A. Velásquez | Mark Green | Jason D. Goodpaster | Jeffrey R. Long
Source: ChemRxiv (preprint, 2020-05-21)
Field: Chemistry — Inorganic Chemistry

Magnetic Ordering via Itinerant Ferromagnetism in a Metal-Organic Framework Materials that combine magnetic order with other desirable physical attributes offer to revolutionize our energy landscape. Indeed, such materials could find transformative applications in spintronics, quantum sensing, low-density magnets, and gas separations. As a result, efforts to design multifunctional magnetic materials have recently moved beyond traditional solid-state materials to metal–organic solids. Among these, metal–organic frameworks in particular bear structures that offer intrinsic porosity, vast chemical and structural programmability, and tunability of electronic properties. Nevertheless, magnetic order within metal–organic frameworks has generally been limited to low temperatures, owing largely to challenges in creating strong magnetic exchange in extended metal–organic solids. Here, we employ the phenomenon of itinerant ferromagnetism to realize magnetic ordering at TC = 225 K in a mixed-valence chromium(II/III) triazolate compound, representing the highest ferromagnetic ordering temperature yet observed in a metal–organic framework. The itinerant ferromagnetism is shown to proceed via a double-exchange mechanism, the first such observation in any metal–organic material. Critically, this mechanism results in variable-temperature conductivity with barrierless charge transport below TC and a large negative magnetoresistance of 23% at 5 K. These observations suggest applications for double-exchange-based coordination solids in the emergent fields of magnetoelectrics and spintronics. Taken together, the insights gleaned from these results are expected to provide a blueprint for the design and synthesis of porous materials with synergistic high-temperature magnetic and charge transport properties. Ferromagnetism ; Spintronics ; Condensed matter physics ; Materials science ; Metal-organic framework ; Magnetoresistance ; Magnetism ; Colossal magnetoresistance ; Valence (chemistry) ; Nanotechnology ; Chemical physics ; Magnetic field ; Adsorption ; Chemistry ; Physics ; Physical chemistry Metal-Organic Frameworks: Synthesis and Applications ; Magnetism in coordination complexes ; Nanocluster Synthesis and Applications
Authors: ФИЦ КНЦ РАН | Г. О. Калашникова | М.Н. Тимофеева | Институт катализа им Г.К. Борескова СО РАН | Е.А. Селиванова | Г.О. Самбуров | Ю.Г. Киселев | Е. С. Щукина | Я.А. Пахомовский
Source: Труды Ферсмановской научной сессии ГИ КНЦ РАН (article, 2020-01-01)
Field: Chemistry — Organic Chemistry

Новые материалы для гетеро- и фотокатализа на основе синтетических титаносиликатных аналогов минералов Хибин 2 Институт катализа им Г Materials science Oxidative Organic Chemistry Reactions ; Marine Sponges and Natural Products ; Catalysis and Oxidation Reactions
Authors: Michael Anghel
Source: Scholarship@Western (Western University) (article, 2020-01-01)
Field: Materials Science — Polymers and Plastics

Synthesis of Stable Organic Radical Homo- and Co-Polymers and Their Applications in Solid-State Devices This thesis outlines the synthesis and characterization of a stable organic radical homopolymer incorporating nitronyl nitroxide radicals, as well as the synthesis and characterization of random and block co-polymers incorporating nitronyl nitroxide and 6-oxoverdazyl radicals.\nThe nitronyl nitroxide homopolymer was synthesized using ring-opening metathesis polymerization (ROMP), yielding polymers with controlled molecular weights and narrow molecular weight distributions. Studies of polymer growth as a function of time and monomer:catalyst ratio revealed the ROMP to be well-behaved. Spectroscopic analysis of the polymer showed that the radicals possessed high radical content, indicating that they are tolerated by ROMP. Conductivity studies of thin-films made of the nitronyl nitroxide polymer were performed, exhibiting memory effects.\nThe nitronyl nitroxide and 6-oxoverdazyl random and block co-polymers were also synthesized using ROMP. It was found that the order of polymerization was key towards generating the block co-polymers. The co-polymers were fully characterized using spectroscopic, thermal, and electrochemical methods. Both radicals were incorporated into the co-polymers, and it was found that there was slightly more nitronyl nitroxide incorporation into the polymers than expected, which was attributed to its faster reaction rate.\nOverall, this work examines the implementation of stable radicals into polymers, while also probing their behaviour as the functional component of solid-state electronics. Polymer ; Solid-state ; Materials science ; Nanotechnology ; Chemistry ; Chemical engineering ; Polymer chemistry ; Polymer science ; Organic chemistry ; Engineering ; Physical chemistry Conducting polymers and applications ; Synthesis and properties of polymers
Authors: Imke A. B. Pijpers
Source: Data Archiving and Networked Services (DANS) (article, 2020-09-18)
Field: Chemistry — Organic Chemistry

Controlled Shape Transformation of Polymersomes: Exploiting Morphology to Introduce Functionality From the extensive expertise that has been built up during the past few decades of biomedical research a particularly interesting platform has emerged as a successful alternative to generic therapeutics: nanoscale particles.Indeed, a wide range of nanoparticles has been developed and successfully applied within the biomedical field.Among these are polymersomes; bi-layered vesicles comprising amphiphilic block copolymers.Polymersomes are interesting candidates for nanomedicine due to their dual-compartmentalized structure; they comprise a hydrophobic membrane and hydrophilic lumen.Recent advances in polymersome development have mainly focused on the improved implementation in biomedical applications by enhancing the biodegradability and -compatibility of the polymer building blocks.Other characteristics, such as size and shape, or morphology, have emerged as key factors for successful implementation in nanomedicine.Additionally, developing such nanoparticles with active transport capacity, further enhances the versatility and dynamicity of these systems.In this introductory Chapter, we give an overview of (i) the development of nanoparticles for application in nanomedicine, (ii) adaptive morphologies based on block copolymer-based nanoparticles and (iii) the development of active nanoparticles as advanced drug carriers.At the end of this Chapter, an outline of this Thesis is presented. Polymersome ; Morphology (biology) ; Transformation (genetics) ; Computer science ; Artificial intelligence ; Materials science ; Biology ; Polymer ; Composite material ; Paleontology ; Copolymer Advanced Polymer Synthesis and Characterization
Authors: Tatiana Rogova | Pablo Gabriel | Stamatia Zavitsanou | Jamie A. Leitch | Fernanda Duarte | Darren J. Dixon
Source: ChemRxiv (preprint, 2020-07-16)
Field: Chemistry — Organic Chemistry

Reverse Polarity Reductive Functionalization of Tertiary Amides via a Dual Iridium Catalyzed Hydrosilylation &amp; SET Strategy A new strategy for the mild generation of synthetically valuable α-amino radicals from robust tertiary amide building blocks has been developed. By combining Vaska’s complex-catalyzed tertiary amide reductive activation and photochemical single electron reduction into a streamlined tandem process, metastable hemiaminal intermediates were successfully transformed into nucleophilic α-amino free radical species. This umpolung approach to such reactive intermediates was exemplified through coupling with an electrophilic dehydroalanine acceptor, resulting in the synthesis of an array of α-functionalized tertiary amine derivatives, previously inaccessible from the amide starting materials. The utility of the strategy was expanded to include secondary amide substrates, intramolecular variants and late stage functionalization of an active pharmaceutical ingredient. DFT analyses were used to establish the reaction mechanism and elements of the chemical system that were responsible for the reaction’s efficiency. Chemistry ; Amide ; Combinatorial chemistry ; Electrophile ; Umpolung ; Nucleophile ; Reductive elimination ; Iridium ; Catalytic cycle ; Catalysis ; Organic chemistry Advanced Synthetic Organic Chemistry ; Radical Photochemical Reactions ; Catalytic Cross-Coupling Reactions
Authors: Jonas Bucevičius | Georgij Kostiuk | Rūta Gerasimaitė | Tanja Gilat | Gražvydas Lukinavičius
Source: bioRxiv (Cold Spring Harbor Laboratory) (preprint, 2020-03-12)
Field: Materials Science — Materials Chemistry

Enhancing biocompatibility of rhodamine fluorescent probes by a neighbouring group effect Abstract Fluorescence microscopy is an essential tool for understanding dynamic processes in living cells and organisms. However, many fluorescent probes for labelling cellular structures suffer from unspecific interactions and low cell permeability. Herein, we demonstrate that the neighbouring group effect which results from positioning an amide group next to a carboxyl group in the benzene ring of rhodamines dramatically increases cell permeability of the rhodamine-based probes through stabilizing a fluorophore in a hydrophobic spirolactone state. Based on this principle, we create probes targeting tubulin, actin and DNA. Their superb staining intensity, tuned toxicity and specificity allows long-term 3D confocal and STED nanoscopy with sub-30 nm resolution. As a result, the real microtubule diameter of 23 nm was resolved inside a living cell for the first time. Due to their unrestricted cell permeability and efficient accumulation on tubulin, the new probes produce high contrast images at sub-nanomolar concentrations. Fluorophore ; STED microscopy ; Fluorescence ; Biophysics ; Rhodamine ; Confocal microscopy ; Confocal ; Chemistry ; Fluorescence microscope ; Microscopy ; Cell biology ; Biology ; Stimulated emission ; Optics Luminescence and Fluorescent Materials ; Click Chemistry and Applications ; Nanoplatforms for cancer theranostics
Authors: Eric C. Hosten | Richard Betz
Source: Zeitschrift für Kristallographie - New Crystal Structures (article, 2020-10-05)
Field: Chemistry — Inorganic Chemistry

Crystal structure of <i>N,N</i>-diphenylformamide, C<sub>13</sub>H<sub>11</sub>NO Abstract C 13 H 11 NO, orthorhombic, Pca 2 1 (no. 29), a = 23.801(4) Å, b = 6.0510(13) Å, c = 7.2677(14) Å, V = 1046.7(3) Å 3 , Z = 4, R gt ( F ) = 0.0335, wR ref ( F 2 ) = 0.0896, T = 200 K. Orthorhombic crystal system ; Crystallography ; Crystal structure ; Crystal (programming language) ; Physics ; Chemistry ; Computer science Crystal structures of chemical compounds ; Synthesis and biological activity ; Metal complexes synthesis and properties
Authors: Julian M. Rotter
Source: Electronic Theses of LMU Munich (Ludwig-Maximilians-Universität München) (article, 2020-01-01)
Field: Materials Science — Materials Chemistry

Molecular frameworks - from morphological control to electronic properties After a good four years of Ph.D. time, there are many people who have contributed in various ways to the creation of this work.I would like to thank them here.First of all, I would like to thank my supervisor Prof. Thomas Bein.Many thanks for the exciting and challenging topic of my dissertation.It was Computer science Machine Learning in Materials Science ; Catalysis and Oxidation Reactions ; Metal-Organic Frameworks: Synthesis and Applications
Authors: Nicholas Roberto da Silva Gobo | Timothy J. Brocksom | Kléber T. de Oliveira
Source: Molecules (article, 2020-05-05)
Field: Materials Science — Materials Chemistry

Synthesis of a Naphthalocyanine-Like Dye: The First Report on Zn(II)-1,6-methano[10]annulenecyanine The synthesis of the new dye 1,6-methano[10]annulenecyanine is described. For this purpose, the 3,4-dicyano-1,6-methano[10]annulene and 3,4-carboxyimide-1,6-methano[10]annulene buildings blocks were synthesized in six to eight steps. In both cases, these building blocks were then cyclotetramerized to furnish a new Zn(II)-1,6-methano[10]annulenecyanine which presents a strong red-shifted absorption band at 800 nm and high solubility in common organic solvents. Annulene ; Absorption (acoustics) ; Solubility ; Chemistry ; Photochemistry ; Combinatorial chemistry ; Materials science ; Organic chemistry Porphyrin and Phthalocyanine Chemistry ; Photodynamic Therapy Research Studies ; Photochromic and Fluorescence Chemistry
Authors: Yuki Arakawa | Kenta Komatsu | Yuko Ishida | Hideto Tsuji
Source: ChemRxiv (preprint, 2020-07-07)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Thioether-Linked Azobenzene-Based Liquid Crystal Dimers Exhibiting the Twist-Bend Nematic Phase over a Wide Temperature Range Two homologous series of sulfur-containing thioether-linked 4-cyanoazobenzene-based liquid crystal (LC) dimers were developed: a symmetric series based on 4-cyanoazobenzene arms [(CN)AzoSnSAzo(CN)] and a non-symmetric series based on 4-cyanoazobenzene and 4-cyanobiphenyl arms [(CN)AzoSnSCB]. They contained different flexible oligomethylene spacers (CnH2n) consisting of odd numbers of carbon atoms (n = 3, 5, 7, 9, and 11). The symmetric (CN)AzoSnSAzo(CN) dimers with n = 5, 7, 9, and 11 showed an elusive monotropic twist–bend nematic (NTB) phase, while all the non-symmetric (CN)AzoSnSCB dimers exhibited the NTB phase. Notably, the NTB phase observed for non-symmetric (CN)AzoS7SCB could be supercooled to room temperature, leading to a glassy NTB phase. (CN)AzoS9SCB showed a similar tendency accompanied by partial crystallization. These are the first reported examples of azobenzene-based LC dimers exhibiting a broad temperature range of NTB phases supercooled to room temperature. Such prominent stability of the NTB phase is due to the supercooling effect assisted by the synergy of molecular bend arising from thioether linkages and non-symmetric mesogenic arms. The phase-transition temperatures were overall higher for symmetric (CN)AzoSnSAzo(CN) than for non-symmetric (CN)AzoSnSCB. It is assumed that the difference in the mesogenic arm structures hardly influenced their molecular geometry or anisotropy in terms of entropy changes. Liquid crystal ; Thioether ; Mesogen ; Supercooling ; Crystallography ; Homologous series ; Phase (matter) ; Columnar phase ; Materials science ; Atmospheric temperature range ; Azobenzene ; Phase transition ; Chemistry ; Mesophase ; Molecule ; Polymer chemistry ; Condensed matter physics ; Organic chemistry ; Thermodynamics ; Physics ; Liquid crystalline Liquid Crystal Research Advancements ; Advanced Materials and Mechanics ; Nonlinear Dynamics and Pattern Formation
Authors: Nadezhda M. Mikova | A. M. Zhizhaev | Ivan P. Ivanov | Maxim A. Lutoshkin | Борис Н. Кузнецов
Source: Journal of Siberian Federal University Chemistry (article, 2020-03-01)
Field: Chemistry — Spectroscopy

Study of the Structure and Properties of Carbon Gels from Abies Lignin and Tannins Carbon tannin-lignin-formaldehyde (TLF) gels were obtained for the first time by carbonization of organic xerogels synthesized by sol-gel condensation of formaldehyde with polyphenolic substances isolated from abies wood and bark – ethanol lignin and condensed tannins. The effect of the mass ratio of the tannins/lignin (T/L) components in the range 1:0 – 1:2 on the specific surface areas, porous volume, apparent density, and microstructure of carbon tannin-lignin-formaldehyde gels has been studied. It was found that the density of the carbon gels increases from 0.52 to 0.60 g/cm3 with a rises in the T/L ratio from 1:0 to 1:0.2 and 1:0.5 in the initial gel and then decreases to 0.20 and 0.13 g/cm3 with an increase in the lignin content to T/L ratios of 1:1 and 1:2, respectively. The study of the porous structure of carbon gels by the BET method showed that the carbon TLF gel obtained at a T/L ratio 1:2 is characterized by the highest specific surface area (538 m2/g). Using scanning electron microscopy, the structures of TF and TLF carbon gels have been studied. It has been established that the size of globular particles has a decisive influence on the structure of gels. The size of the globule particles increases with increasing of lignin content in the composition of the tannin-lignin-formaldehyde gel that leads to the formation of a less ordered structure of the carbon gel. The porous structure of TLF carbon gels obtained from abies polyphenolic substances can be regulated by varying the ratio of tannins:lignin. The obtained carbon gels can be used as sorbents and catalyst supports Lignin ; Formaldehyde ; Carbon fibers ; Tannin ; Chemistry ; Carbonization ; Phenol formaldehyde resin ; Bark (sound) ; Chemical engineering ; Specific surface area ; Materials science ; Nuclear chemistry ; Organic chemistry ; Adsorption ; Composite material ; Catalysis ; Food science Aerogels and thermal insulation ; Adsorption, diffusion, and thermodynamic properties of materials ; Lignin and Wood Chemistry
Authors: S. Sathya | J. Vijayapriya | K. Parasuraman | D. Benny Anburaj | S. Joshua Gnanamuthu
Source: Nanosystems Physics Chemistry Mathematics (article, 2020-12-30)
Field: Materials Science — Materials Chemistry

ZnO nanoparticles as solar photocatalysts: Synthesis, effect of annealing temperature and applications ZnO nanoparticles were prepared by a hydrothermal method from the source materials of Zinc acetylacetonate hydrate and ammonium hydroxide. Further prepared samples were annealed at various temperatures for 3 hours. X-ray diffraction analysiswas employed to study the structure and crystalline nature of synthesized nanoparticles. Scanning electron microscope images showed that the prepared ZnO nanoparticles acquired nano needle, hexagonal disk and porous nanorods structures due to the effect of annealing temperature. The photocatalytic activity of the prepared ZnO nanoparticles was evaluated for Methyl Blue (MB) dye which showed 94% of degradation and good stability for five cycles. Annealing (glass) ; Materials science ; Nanoparticle ; Nanotechnology ; Engineering physics ; Chemical engineering ; Optoelectronics ; Metallurgy ; Engineering ZnO doping and properties ; Copper-based nanomaterials and applications ; Chalcogenide Semiconductor Thin Films