jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Miguel A. Rivero‐Crespo | Georgios Toupalas | Bill Morandi
Source: ChemRxiv (preprint, 2021-06-25)
Field: Materials Science — Materials Chemistry

Preparation of Recyclable and Versatile Porous Poly-Arylthioethers by Reversible Pd-Catalysed C–S/C–S Metathesis Porous organic polymers have shown a number of promising properties; however, their application is usually hampered due to the lability of their linkages. Inspired by the outstanding chemical, mechanical and thermal resistance of the 1D polymer polyphenylene sulphide (PPS), we have designed a new family of 2D and 3D poly-arylthioethers, synthesised via a mild Pd-catalysed C–S/C–S metathesis-based method, that merges the attractive features common to porous polymers and PPS in a single material. In addition, the method is highly modular, allowing to easily introduce application-oriented functionalities in the materials for a series of environmentally relevant applications including metal capture, metal sensing and heterogeneous catalysis. Moreover, despite their extreme chemical resistance, the polymers can be easily recycled to recover the original monomers, offering an attractive perspective for their sustainable use. Polymer ; Metathesis ; Materials science ; Porosity ; Monomer ; Catalysis ; Porous medium ; Modular design ; Chemical engineering ; Nanotechnology ; Polymer chemistry ; Organic chemistry ; Chemistry ; Polymerization ; Computer science ; Composite material Covalent Organic Framework Applications ; Advanced Photocatalysis Techniques ; Perovskite Materials and Applications
Authors: Yan Yang
Source: Thèses en ligne de l'Université Toulouse III (Université Toulouse III) (preprint, 2021-12-17)
Field: Chemistry — Organic Chemistry

Activation de molécules par des complexes mono et multimétalliques ! : Une approche théorique Au cours de cette thèse, nous sommes intéressés à l'étude théorique de l'activation de petites molécules telles que CO2, H2, N2 par des complexes métalliques impliquant des métaux s, d ou encore f. Ce travail a été réalisé en proche collaboration avec des groupes expérimentaux. Le contrôle de la réactivité de ces petites molécules reste un challenge important pour l'industrie chimique mais aussi d'un point de vue sociétal avec par exemple le réchauffement climatique. Nous avons utilisé des techniques de calcul théoriques de mécanisme réactionnels basés sur la théorie de la fonctionnelle de la densité afin de comprendre, expliquer voire prédire l'activité de complexes métalliques vis-à-vis de ces petites molécules. Nous avons par exemple pu montrer que la réduction de O2 par des complexes bimétalliques de fer(II) pouvait se réaliser sous des conditions expérimentales douces par un transfert monoélectronique de chacun des deux centres métalliques. Ce travail a été réalisé en collaboration avec l'équipe du Professeur LaPierre à Atlanta. En collaboration avec le groupe du Professeur Piers à l'université de Calgary, nous avons pu montrer qu'une simple modification d'un ligand sur des complexes de fer ou de cobalt pouvait conduire soit à l'activation facile de la molécule de dioxygène soit à l'activation de la molécule d'ammoniaque (NH3). Ces deux résultats ont marquants car ils montrent que l'on peut facilement moduler la réactivité de complexes de métaux de transition pour permettre ou non d'activer des molécules aussi inertes que O2 ou NH3. Nous avons aussi pu montrer en collaboration avec l'équipe du Professeur Okuda d'Aachen qu'un complexe bimétallique d'hydrure de calcium pouvait réagir avec la molécule de CO et ainsi le fonctionnaliser. Ce travail est une première approche d'une réaction de type Fischer-Tropsch à partir de composé moléculaire. Molecule ; Materials science ; Chemistry ; Organic chemistry Inorganic and Organometallic Chemistry ; History and advancements in chemistry ; Various Chemistry Research Topics
Authors: Benedikt W. Grau | Maximilian Dill | Frank Hampel | Axel Kahnt | Norbert Jux | Svetlana B. Tsogoeva
Source: ChemRxiv (preprint, 2021-03-22)
Field: Chemistry — Organic Chemistry

Metal-Free Four-Step Domino Reaction Enables Fully Controlled Non-Statistical Synthesis of Hexaarylbenzene with Six Different Aryl Groups Hexaarylbenzene (HAB) derivatives are versatile aromatic systems playing a significant role as chromophores, liquid crystalline materials, molecular receptors, redox materials, organic light-emitting diodes and photochemical switches. Statistical synthesis of simple symmetrical HABs is known via low-yielding cyclotrimerization or Diels-Alder reactions. By contrast, the synthesis of more complex, asymmetrical systems, and without involvement of statistical steps, remains an unsolved problem. Here we present a generally applicable synthetic strategy to access asymmetrical HAB via an atom-economical and high-yielding metal-free four-step domino reaction using nitrostyrenes and α,α-dicyanoolefins as easily available starting materials. Resulting domino product – functionalized triarylbenzene (TAB) - can be used as a key starting compound to furnish asymmetrically substituted hexaarylbenzenes in high overall yield and without involvement of statistical steps. This straightforward domino process represents a distinct approach to creating diverse and still unexplored HAB scaffolds, containing six different aromatic rings around central benzene core. Domino ; Cascade reaction ; Chromophore ; Combinatorial chemistry ; Aryl ; Yield (engineering) ; Benzene ; Metal ; Chemistry ; Redox ; Materials science ; Nanotechnology ; Photochemistry ; Organic chemistry ; Catalysis Multicomponent Synthesis of Heterocycles ; Chemical Synthesis and Analysis
Authors: Musammat Muthmanna Abdul Kader
Source:  (preprint, 2021-05-21)
Field: Chemistry — Inorganic Chemistry

Manipulating the Morphology of a Metal-Organic Framework: UiO-66 Metal-Organic Frameworks (MOFs) are an emerging group of crystalline microporous materials that exhibit tunability towards various applications in gas storage, catalysts, and others. This project investigated the effects of reaction variables on UiO-66 via solvothermal synthesis. The results via the direct precipitation route at producing UiO-66 suggested that the crystallization rate was rather stagnant during the 30-day synthesis time, rendering the room temperature synthesis infeasible. Subsequently, the project investigated the effects of stirring time of the reactants for the first time in solvothermal synthesis, temperature, reaction time, modulator ratio, and reactant concentrations, on the morphology of UiO-66. Finally, the project studied the effects of adding glycols as co-solvents on UiO-66 crystal morphology. It was observed that only using ethylene glycol as a co-solvent successfully reformed the morphology of UiO-66 crystals from rounded octahedral crystals to anisotropic needle-like fibers. The results also indicated that diethylene glycol significantly improved the crystallinity of UiO-66 than triethylene glycol did. Ethylene glycol ; Crystallinity ; Materials science ; Solvothermal synthesis ; Diethylene glycol ; Microporous material ; Triethylene glycol ; Metal-organic framework ; Chemical engineering ; Catalysis ; Crystallization ; Solvent ; Nanotechnology ; Morphology (biology) ; Polymer chemistry ; Organic chemistry ; Adsorption ; Chemistry ; Composite material Metal-Organic Frameworks: Synthesis and Applications ; Magnesium Oxide Properties and Applications ; X-ray Diffraction in Crystallography
Authors: Lu, Yaokang
Source: theses.fr (ABES) (article, 2021-12-01)
Field: Materials Science — Materials Chemistry

Nouveaux matériaux à base de cluster de polyoxotitanate Les polyoxotitanates (POT) contenant des rapports bien définis d'atomes de Ti et de métaux dopants et/ou de ligands organiques sont très intéressants car ils sont des précurseurs potentiels pour former des matériaux dopés tels que le TiO2.Dans ce travail, douze clusters POT ont été synthétisés et caractérisés. Puis une série de nouveaux matériaux ont été préparés sur la base de ces POT originaux. Les matériaux composites C@TiO2 ont été utilisés comme matériaux d'électrode pour batterie Li-ion ou comme supercondensateurs. Les matériaux PEDOT:Ce@TiO2, PTEPA-Ti, Poly-(EDOT-POT-1) présentent une forte surface hydrophobe et des propriétés électrochromes prometteuses. En particulier, le film nanoporeux Poly-(EDOT-POT)-1, obtenu à partir de Ti6O6(TA)6(iPrO)6) (POT-1, TA = thiophène-3-acétate) est adapté au transport d'ions rapides et présente des propriétés électrochromes améliorées par rapport au PEDOT.Finalement, un copolymère à base de porphyrine et du POT-1 a été obtenu. Le film Poly-(H2P-POT-1) présente un bon comportement de génération pour la génération de photocourant. Agrégation ; Homogeneous ; Base (topology) ; Cluster (spacecraft) Polyoxometalates: Synthesis and Applications ; Chemical Synthesis and Characterization ; TiO2 Photocatalysis and Solar Cells
Authors: F.F.H. Aragón
Source: Research Square (preprint, 2021-09-29)
Field: Materials Science — Materials Chemistry

Enhancement of the Photocatalytic Activity of ZnO Nanoparticles and the Relationship With Thermal Annealing Temperature Abstract The present study describes the synthesis, characterization, and photocatalytic activity (PCA) evaluation of ZnO nanoparticles (NPs) prepared via the polymeric precursor method in a first step, following annealing in the range of 500 to 900 o C in a second step. The formation of the wurtzite crystal structure is confirmed via x-ray diffraction data analysis. Thermal annealing treatments in atmospheric air are carried out to control the crystallite mean size and physical properties. The UV-Vis spectroscopy measurements show a decreasing trend of the optical band gap of the as-fabricated ZnO NPs, from ~3.4 eV to ~3.1 eV, as the annealing temperature increases. The PCA of the ZnO NPs against methylene blue dye revealed an increase in efficiency as the annealing temperature increases, reaching with a maximum performance for the sample annealed at ~700 °C. Our findings suggest that the PCA of the ZnO NPs does not show a straightforward dependence on the NPs’ size, but it seems to be correlated with the density of defects, such as oxygen vacancies, which are modulated by the annealing temperature. In addition, thermoluminescence glow curves exhibit a well-defined peak located at ~622 K for the as-prepared ZnO nanopowder. The peak intensity shows a decreasing trend with the annealing temperature up to ~700 °C. This result is correlated with the modulation of traps as the annealing temperature increases, which seems to be directly related to the amount of trapped charges (electrons and holes), leading to a marked reduction of the PCA. Photocatalysis ; Annealing (glass) ; Nanoparticle ; Materials science ; Thermal ; Nanotechnology ; Chemical engineering ; Chemistry ; Composite material ; Catalysis ; Physics ; Thermodynamics ; Engineering ZnO doping and properties ; Gas Sensing Nanomaterials and Sensors ; Copper-based nanomaterials and applications
Authors: Hao Lyu | Oscar Iu‐Fan Chen | Nikita Hanikel | Mohammad I. Hossain | Robinson W. Flaig | Xiaokun Pei | Ameer Amin | Mark D. Doherty | Rebekah K. Impastato | T. Grant Glover | David R. Moore | Omar M. Yaghi
Source: ChemRxiv (preprint, 2021-12-21)
Field: Chemistry — Inorganic Chemistry

Carbon Dioxide Capture Chemistry of Amino Acid Functionalized Metal-Organic Frameworks in Humid Flue Gas Metal-organic framework-808 has been functionalized with 11 amino acids (AA) to produce a series of MOF-808-AA structures. The adsorption of CO2 under flue gas conditions revealed that glycine- and DL-lysine-functionalized MOF-808 (MOF-808-Gly and -DL-Lys) have the highest uptake capacities. Enhanced CO2 capture performance in the presence of water was observed and studied using single-component sorption isotherms, CO2/H2O binary isotherm, and dynamic breakthrough measurements. The key to the favorable performance was uncovered by deciphering the mechanism of CO2 capture in the pores and attributed to the formation of bicarbonate as evidenced by 13C and 15N solid-state nuclear magnetic resonance spectroscopy studies. Based on these results, we examined the performance of MOF-808-Gly in simulated coal flue gas conditions and found that it is possible to capture and release CO2 by vacuum swing adsorption. MOF-808-Gly was cycled at least 80 times with full retention of performance. This study significantly advances our understanding of CO2 chemistry in MOFs by revealing how strongly bound amine moieties to the MOF backbone create the chemistry and environment within the pores, leading to the binding and release of CO2 under mild conditions without application of heat. Flue gas ; Chemistry ; Adsorption ; Sorption ; Metal-organic framework ; Carbon dioxide ; Amine gas treating ; Bicarbonate ; Chemical engineering ; Inorganic chemistry ; Organic chemistry Metal-Organic Frameworks: Synthesis and Applications ; Carbon Dioxide Capture Technologies ; Membrane Separation and Gas Transport
Authors: Michele Formica | Tatiana Rogova | Heyao Shi | Naoto Sahara | Alistair J. M. Farley | Kirsten E. Christensen | Fernanda Duarte | Darren J. Dixon
Source: ChemRxiv (preprint, 2021-07-21)
Field: Chemistry — Organic Chemistry

Catalytic Enantioselective Nucleophilic Desymmetrisation of PhosphonateEsters Compounds containing one or more stereogenic phosphorous atoms in the P(V) oxidation state are important to chemistry, biology and medicine. These include marketed antiviral drugs such as Tenofovir alafenamide and Remdesivir, an effective treatment for Ebola which has also recently been approved for use against SARS-CoV-2 in the US. Existing approaches for the stereoselective synthesis of P-stereogenic centers, while elegant, remain mostly diastereoselective, with catalytic enantioselective approaches remaining limited in application. Accordingly, conceptually novel, broad-scope, catalytic strategies for the efficient stereoselective synthesis of diverse stereogenic P(V) containing compounds remain essential. To this end, we describe a novel enantioselective two-stage strategy, exploiting the first catalytic and highly enantioselective desymmetrisation of phosphonate esters. Pivoting on the stereocontrolled, sequential nucleophilic substitution of enantiotopic leaving groups from readily accessible pro-chiral P(V) precursors, a bifunctional iminophosphorane (BIMP) superbase catalyst was found to be essential in delivering reactive desymmetrised intermediates capable of downstream enantiospecific substitution. This uniquely modular, catalytic platform allows broad-scope, stereoselective access to a diverse library of chiral P(V) compounds including those with O, N and S-linkages. Enantioselective synthesis ; Stereocenter ; Nucleophile ; Stereoselectivity ; Phosphonate ; Chemistry ; Stereochemistry ; Combinatorial chemistry ; Bifunctional ; Catalysis ; Annulation ; Organic chemistry Synthetic Organic Chemistry Methods ; Asymmetric Hydrogenation and Catalysis ; Organophosphorus compounds synthesis
Authors: Yaokang Lu
Source: Serveur des thèses de l'Université de Strasbourg (University of Strasbourg) (preprint, 2021-12-01)
Field: Materials Science — Materials Chemistry

Novel materials based on polyoxotitanate clusters Polyoxotitanates (POT) containing well-defined ratios of Ti atoms and dopant metals and / or organic ligands are of great interest because they are potential precursors to form doped materials such as TiO2.In this work, twelve POT clusters were synthesized and characterized. Then a series of new materials were prepared on the basis of these original POTs. C@TiO2 composite materials have been used as electrode materials for Li-ion batteries or as supercapacitors. PEDOT materials: Ce@TiO2, PTEPA-Ti, Poly-(EDOT-POT-1) exhibit a strong hydrophobic surface and promising electrochromic properties. In particular, the nanoporous Poly-(EDOT-POT)-1 film, obtained from Ti6O6(TA)6(iPrO)6) (POT-1, TA = thiophene-3-acetate) is suitable for ion transport fast and has improved electrochromic properties compared to PEDOT.Finally, a copolymer based on porphyrin and POT-1 was obtained. Poly-(H2P-POT-1) film exhibits good generation behavior for photocurrent generation. Computer science Polyoxometalates: Synthesis and Applications ; Chemical Synthesis and Reactions ; Metal-Organic Frameworks: Synthesis and Applications
Authors: Polina R. Ware
Source: Scholarworks (University of Massachusetts Amherst) (article, 2021-04-01)
Field: Materials Science — Polymers and Plastics

Polymer Modification with Multifunctional Additives and Unique Processing Methods Glycosaminoglycans (GAGs), highly charged biological polyelectrolytes, are of growing importance as biomaterials and pharmaceutical drugs due to their immense range of physiological functions. They bind to many proteins; however, the degree of structural selectivity in GAG-protein interactions is largely unknown .Our studies have focused on the importance of heparin (a model GAG) charge and chain length in protein binding in order to explore its potential applications in biofunctional tissue scaffold materials, as polysaccharide drugs in anticoagulation, and as inhibitory agents in protein aggregation. We used electrospray ionization mass spectrometry, capillary electrophoresis, size exclusion chromatography, dynamic/static light scattering and electrostatic protein modeling. Polymer ; Polymer science ; Materials science ; Composite material Polymer Nanocomposites and Properties ; Advanced Polymer Synthesis and Characterization ; Polymer crystallization and properties
Authors: Jesper Dahl Jensen | Niels Bisballe | Laura Kacenauskaite | Maria Storm Thomsen | Junsheng Chen | Ole Hammerich | Bo W. Laursen
Source: ChemRxiv (preprint, 2021-09-02)
Field: Chemistry — Organic Chemistry

Utilizing selective chlorination to synthesize new triangulenium dyes Access to functionalization of new sites on the triangulenium core structure has been achieved at an early stage by chlorination with N-chlorosuccinimide (NCS), giving rise to two new triangulenium dyes (1 and 2). By introducing the chlorine functionalities in the acridinium precursor, positions complementary to those previously accessed by electrophilic aromatic substitution of the final dyes can be accesed. The chlorination is selective, giving only one regioisomer for both mono- and dichlorination products. For the monochlorinated acridinium compound a highly selective ring-closing reaction was discovered to generate only a single regioisomer of the cationic [4]helicene product. This discovery aspired further investigations into the mechanism of [4]helicene formation and to the first isolation of the previously proposed intermediate of the two-step SNAr reaction, key to all aza-bridged triangulenium and helicenium systems. A late stage functionalization of DAOTA+ with NCS gave rise to a different dichlorinated compound (2). The fully ring closed chlorinated triangulenium dyes 1, 2 and 3 show a redshift in absorption and emission relative to the non-chlorinated analogues, while still maintaining relatively high fluorescence quantum yields of 36%, 26%, and 41%, and long fluorescence lifetimes of 15 ns, 12.5 ns and 16 ns, respectively. Cyclic voltammetry shows that chlorination of the triangulenium dyes significantly lowers reduction potentials and thus allows for efficient tuning of redox and photo-redox properties. Chemistry ; Helicene ; Structural isomer ; Combinatorial chemistry ; Electrophilic substitution ; Redox ; Fluorescence ; Cationic polymerization ; Ring (chemistry) ; Photochemistry ; Halogenation ; Organic chemistry ; Molecule Synthesis and Properties of Aromatic Compounds ; Photochromic and Fluorescence Chemistry ; Porphyrin and Phthalocyanine Chemistry
Authors: Xiongbo Dong | Zitong Chen | Aidong Tang | Dionysios D. Dionysiou | Yang Hua-ming
Source: Research Square (preprint, 2021-06-12)
Field: Chemistry — Organic Chemistry

Natural mineral modulated single atom catalyst for effective water treatment Natural (archaeology) ; Mineral ; Natural mineral ; Catalysis ; Atom (system on chip) ; Mineral water ; Environmental science ; Chemistry ; Materials science ; Mineralogy ; Geology ; Metallurgy ; Computer science Nanomaterials for catalytic reactions ; Catalytic Processes in Materials Science ; Advanced Photocatalysis Techniques
Authors: Sayuri L. Higashi | Masato Ikeda
Source: ChemRxiv (preprint, 2021-03-03)
Field: Materials Science — Biomaterials

Development of an Amino Sugar-Based Supramolecular Hydrogelator with Reduction Responsiveness Stimuli-responsive supramolecular hydrogels are a newly emerging class of aqueous soft materials with a wide variety of bioapplications. Here we report a reduction-responsive supramolecular hydrogel constructed from a markedly simple low-molecular-weight hydrogelator, which is developed on the basis of modular molecular design containing a hydrophilic amino sugar and a reduction-responsive nitrophenyl group. The hydrogel formation ability differs significantly between glucosamine- and galactosamine-based self-assembling molecules, which are epimers at the C4 position, and only the glucosamine-based derivative can act as a hydrogelator. Supramolecular chemistry ; Epimer ; Chemistry ; Self-healing hydrogels ; Glucosamine ; D-Glucosamine ; Galactosamine ; Aqueous solution ; Combinatorial chemistry ; Derivative (finance) ; Modular design ; Molecule ; Stereochemistry ; Organic chemistry ; Business ; Computer science Supramolecular Self-Assembly in Materials ; Glycosylation and Glycoproteins Research ; Proteoglycans and glycosaminoglycans research
Authors: Zhao Gao | Shuai Qiu | Fei Yan | Shuyi Zhang | Wei Tian
Source: Research Square (preprint, 2021-02-10)
Field: Materials Science — Biomaterials

Time-Encoded Bio-Fluorochromic Supramolecular Co-Assembly for Rewritable Security Printing Abstract Innovative fluorescence security technologies for paper-based information are still highly pursued now-adays because data leakage and indelibility have become serious economic and social problems. Herein, we report a novel transient biofluorochromic supramolecular co-assembly mediated by hydrolytic enzyme (ALP: alkaline phosphatase) towards rewritable security printing. A co-assembly based on the de-signed tetrabranched cationic diethynylanthracene monomer tends to be formed by adding adenosine triphosphate (ATP) as the biofuel. The resulting co-assembly possesses a time-encoded bio-fluorochromic feature, upon successively hydrolyzing ATP by ALP and re-adding new batches of ATP. On this basis, the dynamic fluorescent properties of this time-encoded co-assembly system have been successfully enabled in rewritable security patterns via an inkjet printing technique, providing a fascinating potential for fluorescence security materials with a biomimetic mode. Supramolecular chemistry ; Fluorescence ; Cationic polymerization ; Nanotechnology ; Supramolecular assembly ; Adenosine triphosphate ; Chemistry ; Computer science ; Materials science ; Biochemistry ; Polymer chemistry ; Organic chemistry Supramolecular Self-Assembly in Materials ; Luminescence and Fluorescent Materials ; Supramolecular Chemistry and Complexes