Download or read book Nickel and Cobalt Bis imino pyridine Complexes as Catalysts for the Hydrogen Evolution Reaction written by Bing Jiang and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: El subministrament d'energia sostenible és un desafiament crític que enfronta la humanitat. La dependència dels combustibles fòssils ha despertat l'interès en el desenvolupament de fonts d'energia lliures de carboni, entre les quals el dihidrogen que té una alta densitat d'energia seria un dels més prometedors sempre que es generi a partir d'alternatives renovables. En aquest context, dissociar l'aigua per produir hidrogen com a combustible és de gran interès i, per tant, s'estan desenvolupant una gran quantitat de catalitzadors per accelerar la velocitat d'aquesta reacció, preferiblement obtinguts a partir de metalls de transició abundants. Amb l'objectiu d'optimitzar l'economia de l'àtom de metall i facilitar l'anàlisi mecanístic, els complexos moleculars són una bona opció com a catalitzadors homogenis. En aquest tipus de compostos, els centres metal·lics que generalment es requereixen poden accedir a múltiples estats d'oxidació, de vegades a través d'intermedis de tipus metall-hidrur. No obstant això, el disseny de catalitzadors per a la reacció d'evolució de l'hidrogen (HER) inclou també una família de complexos amb lligands no innocents que poden operar com un reservori d'electrons i / o un lloc de protonació. El primer capítol d'aquesta tesi doctoral introdueix la necessitat i les tècniques per a la producció d'hidrogen per recolzar la demanda d'energia, incloent els electrocatalitzadors per HER basats en els metalls no nobles, níquel i cobalt. El segon capítol descriu els objectius d'aquesta Tesi, és a dir, la síntesi i caracterització dels lligands basats en diiminpiridina (PDI), actius en redox, juntament amb els complexos de níquel i cobalt obtingut a partir d'aquests lligands. Es presenten també com a objectius la seva avaluació electrocatalítica en HER així com la descripció dels processos des del punt de vista mecanístic. El tercer capítol presenta la preparació d'un conjunt de lligands PDI pentadentats, juntament amb la síntesi i caracterització completa de complexos de Ni(II) de hexacoordinats [Ni(Ph2PPrPDI)(Cl)](Cl) (1(Cl)) i [Ni(Ph2PPrPDI)(p)Cl)(Cl)](Cl) (2(Cl)). La ubicació dels electrons després de la reducció electroquímica d'1(Cl) es va examinar mitjançant càlculs de la teoria del funcional de la densitat (DFT) juntament amb la ressonància paramagnètica electrònica (EPR), la qual cosa va mostrar que la primera reducció d'un electró es produeix en el metall i la segona en el lligand. Es van estudiar també les propietats redox i catalítiques d'ambdós complexos. D'una banda, es va observar un potencial redox més positiu i, per tant, un sobrepotencial més baix per a 2(Cl), el que indica que la presència del substituent electroatraient Cl al lligand PDI millora l'activitat electrocatalítica. D'altra banda, 1(Cl) és més actiu per al HER en termes de TOF i constant de velocitat. Els estudis d'estabilitat a curt termini per a 1(Cl) i 2(Cl) en condicions de HER per CV indiquen que la catàlisi és homogènia sense descomposició, mentre que l'estabilitat a llarg termini analitzada per electròlisi potencial controlada mostra la generació d'una nova espècie transitòria que pot desencadenar la reacció d'oxidació d'hidrogen i al seu torn reduir el sobrepotencial per a la HER. El quart capítol s'enfoca en la síntesi i caracterització de complexos de Co coordinats de cinc amb els lligands aplicats en el tercer capítol ([CoI(Ph2PPrPDI](BF4), 3(BF4) i [CoI(Ph2PPrPDI(p)Cl](BF4), 4(BF4)). Les dades de l'electroquímica mostren que aquests complexos són actius per a la HER en medi orgànic, passant després de la reacció amb protons per espècies d'hidrur de Co(III) que es van identificar mitjançant espectroscòpia UV-vis i RMN. Sobre la base de l'espectroscòpia RMN, el compost de Co(I) inicial es va recuperar després d'un cicle de reacció catalític, el que demostra un mecanisme homolític per HER. Finalment, el cinquè capítol enumera les conclusions més rellevants extretes del treball realitzat.
Download or read book Preparing and Characterizing Bis imino pyridine Complexes of Nickel Iron and Cobalt for Electrocatalytic Hydrogen Evolution written by Samuel J. Underwood and published by . This book was released on 2016 with total page 63 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book CO2 Hydrogenation Catalysis written by Yuichiro Himeda and published by John Wiley & Sons. This book was released on 2021-06-28 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: A guide to the effective catalysts and latest advances in CO2 conversion in chemicals and fuels Carbon dioxide hydrogenation is one of the most promising and economic techniques to utilize CO2 emissions to produce value-added chemicals. With contributions from an international team of experts on the topic, CO2 Hydrogenation Catalysis offers a comprehensive review of the most recent developments in the catalytic hydrogenation of carbon dioxide to formic acid/formate, methanol, methane, and C2+ products. The book explores the electroreduction of carbon dioxide and contains an overview on hydrogen production from formic acid and methanol. With a practical review of the advances and challenges in future CO2 hydrogenation research, the book provides an important guide for researchers in academia and industry working in the field of catalysis, organometallic chemistry, green and sustainable chemistry, as well as energy conversion and storage. This important book: Offers a unique review of effective catalysts and the latest advances in CO2 conversion Explores how to utilize CO2 emissions to produce value-added chemicals and fuels such as methanol, olefins, gasoline, aromatics Includes the latest research in homogeneous and heterogeneous catalysis as well as electrocatalysis Highlights advances and challenges for future investigation Written for chemists, catalytic chemists, electrochemists, chemists in industry, and chemical engineers, CO2 Hydrogenation Catalysis offers a comprehensive resource to understanding how CO2 emissions can create value-added chemicals.
Download or read book A Cobalt Complex of Bis Methylthioether Pyridine Catalyst for Hydrogen Evolution from Water written by chunli wang and published by . This book was released on 2020 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new cobalt-based catalyst, [(btep)CoBr 2 ] is produced by the reaction of CoBr 2 and bis(methylthioether)pyridine (btep), and its structure has been determined by X-ray crystallography. Our experiments suggest that this cobalt complex can used as a molecular catalyst for electrochemical and photochemical driven hydrogen evolution. As an electrocatalyst, this cobalt complex can provide 591.9 moles of hydrogen per mole of catalyst per hour (mol H 2 /mol catalyst/h) from a neutral water under an overpotential (OP) of 837.6 mV. As a co-catalyst, it was mixed with CdS nanorods (CdS NRs) as a photosensitizer, and ascorbic acid (H 2 A) as a sacrificial electron donor, and [(btep)CoBr 2 ] can provide 9326.4 mol H 2 per mole of catalyst during 40 h irradiation. The highest apparent quantum yield (AQY) is ~25.5%. The catalytic mechanism for H 2 production is investigated by several measurements and analysis.
Download or read book Olefin Polymerization written by Walter Kaminsky and published by Wiley-VCH. This book was released on 2006-08-18 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: With an enormous velocity, olefin polymerization has expanded to one of the most significant fields in polymers since the first industrial use about 50 years ago. In 2005, 100 million tons of polyolefins were produced - the biggest part was catalyzed by metallorganic compounds. The Hamburg Macromolecular Symposium 2005 with the title "Olefin Polymerization" involved topics such as new catalysts and cocatalysts, kinetics, mechanism and polymer reaction engineering, synthesis of special polymers, and characterization of polyolefins. The conference combined scientists from different disciplines to discuss latest research results of polymers and to offer each other the possibility of cooperation. This is reflected in this volume, which contains invited lectures and selected posters presented at the symposium.
Download or read book Pincer Compounds written by David Morales-Morales and published by Elsevier. This book was released on 2018-04-11 with total page 756 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pincer Compounds: Chemistry and Applications offers valuable state-of-the-art coverage highlighting highly active areas of research—from mechanistic work to synthesis and characterization. The book focuses on small molecule activation chemistry (particularly H2 and hydrogenation), earth abundant metals (such as Fe), actinides, carbene-pincers, chiral catalysis, and alternative solvent usage. The book covers the current state of the field, featuring chapters from renowned contributors, covering four continents and ranging from still-active pioneers to new names emerging as creative strong contributors to this fascinating and promising area. Over a decade since the publication of Morales-Morales and Jensen's The Chemistry of Pincer Compounds (Elsevier 2007), research in this unique area has flourished, finding a plethora of applications in almost every single branch of chemistry—from their traditional application as very robust and active catalysts all the way to potential biological and pharmaceutical applications. - Describes the chemistry and applications of this important class of organometallic and coordination compounds - Includes contributions from global leaders in the field, featuring pioneers in the area as well as emerging experts conducting exciting research on pincer complexes - Highlights areas of promising and active research, including small molecule activation, earth abundant metals, and actinide chemistry
Download or read book Nanotechnology Based Industrial Applications of Ionic Liquids written by Inamuddin and published by Springer Nature. This book was released on 2020-09-03 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt: Numerous solvents used in chemical processes have poisonous and unsafe properties that pose significant ecological concerns ranging from atmospheric emissions to the contamination of water effluents. To combat these ecological threats, over the course of the past two decades, the field of green chemistry has grown to develop more natural reaction processes and techniques involving the use of nonconventional solvents to diminish waste solvent production and thus decrease negative impact on the environment. Ionic liquids in particular are more environmentally friendly substitutes to conventional solvents, and as such, have seen more widespread use in the past decade. They have been used in such processes as extraction, separation, purification of organic, inorganic, and bioinorganic compounds, reaction media in biochemical and chemical catalysis, green organic and drug synthesis, among other industrial applications. Thus, in proving themselves a suitable greener media for economic viability in chemical processes, ionic liquids are leading to more sustainable development. This edition explores the application of ionic liquids as a green solvent. It contains a state-of-the-art overview on ionic liquids as green solvents for chemical processes and techniques, as well as some of their useful industrial applications.
Download or read book Catalysis without Precious Metals written by R. Morris Bullock and published by John Wiley & Sons. This book was released on 2011-08-02 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written for chemists in industry and academia, this ready reference and handbook summarizes recent progress in the development of new catalysts that do not require precious metals. The research thus presented points the way to how new catalysts may ultimately supplant the use of precious metals in some types of reactions, while highlighting the remaining challenges. An essential copanion for organic and catalytic chemists, as well as those working with/on organometallics and graduate students. From the contents: * Catalysis Involving the H' Transfer Reactions of First-Row Transition Metals * Catalytic Reduction of Dinitrogen to Ammonia by Molybdenum Complexes * Molybdenum and Tungsten Catalysts for Hydrogenation, Hydrosilylation and Hydrolysis * Iron in Catalytic Alkene and Carbonyl Hydrogenation Reactions * Olefin Oligomerizations and Polymerizations Catalyzed by Iron and Cobalt Complexes * Cobalt and Nickel Catalyzed Reactions Involving C-H and C-N Activation Reactions * Development of Molecular Electrocatalysts for H2 Oxidation and Production Based on Inexpensive Metals * Nickel-Catalyzed Reductinve Couplings and Cyclizations * Copper-Catalyzed Ligand Promoted Ullmann-Type Coupling Reactions * Copper-Catalyzed Azide-Alkyne Cycloaddition * "Frustrated Lewis Pairs": A Metal-Free Strategy for Hydrogenation Catalysis
Download or read book Iron Catalysis written by Bernd Plietker and published by Springer Science & Business Media. This book was released on 2011-01-05 with total page 227 pages. Available in PDF, EPUB and Kindle. Book excerpt: Juan I. Padrón and Víctor S. Martín: Catalysis by means of Fe-based Lewis acids; Hiroshi Nakazawa*, Masumi Itazaki: Fe–H Complexes in Catalysis; Kristin Schröder, Kathrin Junge, Bianca Bitterlich, and Matthias Beller: Fe-catalyzed Oxidation Reactions of Olefins, Alkanes and Alcohols: Involvement of Oxo- and Peroxo Complexes; Chi-Ming Che, Cong-Ying Zhou, Ella Lai-Ming Wong: Catalysis by Fe=X Complexes (X=NR, CR2); René Peters, Daniel F. Fischer and Sascha Jautze: Ferrocene and Half Sandwich Complexes as Catalysts with Iron Participation; Markus Jegelka, Bernd Plietker: Catalysis by Means of Complex Ferrates.
Download or read book Bis imino pyridine Iron and Cobalt Complexes written by Amanda Catherine Bowman and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The synthesis, reactivity and electronic structures of a series of bis(imino)pyridine iron and cobalt complexes was investigated. A series of monomeric bis(imino)pyridine cobalt dinitrogen complexes was investigated using a combination of 1H NMR and infrared spectroscopies, X-ray crystallography, EPR spectroscopy, solution and solid state magnetic measurements and density functional theory. The neutral bis(imino)pyridine cobalt dinitrogen complexes have doublet ground states and are best described as low-spin cobalt(I) centers with an unpaired electron on the singly reduced chelate, while the anionic bis(imino)pyridine cobalt dinitrogen complexes are also best described as low-spin cobalt(I) centers with dianionic chelates. These investigations established that reduction of monochloride precursors occurs at the metal center, in contrast to the related bis(imino)pyridine iron bis(dinitrogen) complex, (iPrPDI)Fe(N2)2, where reduction of the chelate is observed. A series of bis(imino)pyridine iron imide complexes was also investigated. A combination of Xray crystallography, variable temperature SQUID magnetization data and Mössbauer spectroscopy was used to elucidate the electronic structures of these complexes. In contrast to the previously reported N-aryl substituted bis(imino)pyridine iron imide complexes, where an iron(III) metal center and a singly reduced chelate was observed, an iron(IV) metal center and a triplet diradical chelate was observed for N-alkyl substituted bis(imino)pyridine iron imide complexes. For (iPrPDI)FeN(2Ad) (iPrPDI = 2,6-(2,6-iPr2-C6H3-N=CMe)2C5H3N), thermal spin crossover from S = 0 to S = 1 was observed when warming from 15 K to 200 K. (ArPDI)FeNR compounds with an S = 0 ground state promoted C-H bond activation of both imine methyl groups of the bis(imino)pyridine ligand. The C-H bond activation with (iPrPDI)FeN(CyOct) was firstorder in iron with a rate constant of k = 3.4(2)x10-5 s-1 at 25 °C and a primary kinetic isotope effect of 3.3(2), consistent with a rate-determining step of intramolecular C-H bond activation. In contrast, no C-H bond activation of the ligand was observed for the iron imide complexes that are S = 1 at 23 °C. The reactivity of bis(imino)pyridine iron imide compounds with hydrogen, silanes, terminal alkynes and organic azides, and the electronic structures of the resulting iron complexes, was also investigated.
Download or read book Synthesis and Characterization of Cobalt and Nickel Thiolate Complexes for Hydrogen Evolution written by and published by . This book was released on 2015 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hydrogen Transfer Reactions written by Gabriela Guillena and published by Springer. This book was released on 2016-09-27 with total page 393 pages. Available in PDF, EPUB and Kindle. Book excerpt: The series Topics in Current Chemistry Collections presents critical reviews from the journal Topics in Current Chemistry organized in topical volumes. The scope of coverage is all areas of chemical science including the interfaces with related disciplines such as biology, medicine and materials science. The goal of each thematic volume is to give the non-specialist reader, whether in academia or industry, a comprehensive insight into an area where new research is emerging which is of interest to a larger scientific audience. Each review within the volume critically surveys one aspect of that topic and places it within the context of the volume as a whole. The most significant developments of the last 5 to 10 years are presented using selected examples to illustrate the principles discussed. The coverage is not intended to be an exhaustive summary of the field or include large quantities of data, but should rather be conceptual, concentrating on the methodological thinking that will allow the non-specialist reader to understand the information presented. Contributions also offer an outlook on potential future developments in the field.
Download or read book Applied Cross Coupling Reactions written by Yasushi Nishihara and published by Springer Science & Business Media. This book was released on 2012-12-14 with total page 247 pages. Available in PDF, EPUB and Kindle. Book excerpt: “Applied Cross-Coupling Reactions” provides students and teachers of advanced organic chemistry with an overview of the history, mechanisms and applications of cross-coupling reactions. Since the discovery of the transition-metal-catalyzed cross-coupling reactions in 1972, numerous synthetic uses and industrial applications have been developed. The mechanistic studies of the cross-coupling reactions have disclosed that three fundamental reactions: oxidative addition, transmetalation, and reductive elimination, are involved in a catalytic cycle. Cross-coupling reactions have allowed us to produce a variety of compounds for industrial purposes, such as natural products, pharmaceuticals, liquid crystals and conjugate polymers for use in electronic devices. Indeed, the Nobel Prize for Chemistry in 2010 was awarded for work on cross-coupling reactions. In this book, the recent trends in cross-coupling reactions are also introduced from the point of view of synthesis design and catalytic activities of transition-metal catalysts.
Download or read book Molecular Catalysts for CO2 Fixation Reduction written by Hitoshi Ishida and published by Frontiers Media SA. This book was released on 2020-03-20 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis and Reactivity of a N pyrrolyl Bis imino pyridine Cobalt Complex written by Damon A. Mclean and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Zinc Catalysis written by Stephan Enthaler and published by John Wiley & Sons. This book was released on 2015-04-27 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt: Filling the gap in the market for comprehensive coverage of this hot topic, this timely book covers a wide range of organic transformations, e. g. reductions of unsaturated compounds, oxidation reactions, Friedel-Crafts reactions, hydroamination reactions, depolymerizations, transformations of carbon dioxide, oxidative coupling reactions, as well as C-C, C-N, and C-O bond formation reactions. A chapter on the application of zinc catalysts in total synthesis is also included. With its aim of stimulating further research and discussion in the field, this is a valuable reference for professionals in academia and industry wishing to learn about the latest developments.
Download or read book COSMO RS written by Andreas Klamt and published by Elsevier. This book was released on 2005-07-26 with total page 247 pages. Available in PDF, EPUB and Kindle. Book excerpt: The COSMO-RS technique is a novel method for predicting the thermodynamic properties of pure and mixed fluids which are important in many areas, ranging from chemical engineering to drug design. COSMO-RS, From Quantum Chemistry to Fluid Phase Thermodynamics and Drug Design is about this novel technology, which has recently proven to be the most reliable and efficient tool for the prediction of vapour-liquid equilibria. In contrast to group contribution methods, which depend on an extremely large number of experimental data, COSMO-RS calculates the thermodynamic data from molecular surface polarity distributions, resulting from quantum chemical calculations of the individual compounds in the mixture. In this book, the author cleverly combines a vivid overview of the partly demanding theoretical steps with a deeper analysis of their scientific background and justification. Aimed at theoretical chemists, computational chemists, physical chemists, chemical engineers, thermodynamicists as well as students,academic and industrial experts, COSMO-RS, From Quantum Chemistry to Fluid Phase Thermodynamics and Drug Design provides a novel viewpoint to anyone looking to gain more insight into the theory and potential of the unique method, COSMO-RS. - The only book currently available on COSMO-RS technique - Provides a novel viewpoint for the scientific understanding and for the practical quantitative treatment of fluid phase thermodynamics - Includes illustrative examples of the COSMOtherm program
