Download or read book Rhenium catalyzed Heteroatom Transfer Reactions written by Marc C. Perry and published by . This book was released on 2000 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Reactions and Mechanisms of Rhenium Catalyzed Oxygen Atom Transfer written by Joachin Jude Arias and published by . This book was released on 2001 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Rhenium catalyzed Oxygen atom Transfer Reactions written by Eric C. Brown and published by . This book was released on 2002 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: In situ reduction of hydrido-tris-(3,5-dimethylpyrazolyl)borato(trioxo) rhenium(V) with triphenylphosphine or triethylphosphite leads to a reactive rhenium(V) species that catalytically deoxygenates epoxides at 75-105°C. The reaction is stereospecific, except for trans- and cis-butene oxide which formed minor amounts of the opposite isomer. A variety of different functional groups were tolerated and even epoxides that reacted slowly could be pushed to greater than 95% conversion given extended time and/or higher temperature. The absence of clustering processes shows how the choice of ligand can have a major influence on the design of the catalytic cycle. The rhenium(V) species formed from reduction of Tp'ReO3 was identified as Tp'Re(O)(OH)2. Tp'Re(O)(OH)2 reacted with ethanol and HCl to form ethoxide and hydroxo chloride complexes, respectively. In addition, Tp'Re(O)(OH)2 was an excellent catalytic and stoichiometric reagent for the deoxygenation of epoxides and sulfoxides. Loss of water from Tp'Re(O)(OH)2 to form the catalytically active species Tp'Re02 was shown to be a necessary preequilibrium process. The kinetic behavior of the catalytic system is complex. First-order behavior in [Re][subscript T], zero-order dependence in [PPh3] and saturation behavior for epoxide were observed. The reversible formation of a coordinated epoxide complex was proposed to explain the saturation behavior. The epoxide complex was shown experimentally and computationally to engage in two separate reactions: ring expansion to form a syn-diolate complex, and direct fragmentation to alkene and trioxide. A steady-state concentration of diolate is eventually reached explaining a "burst" of alkene production prior to generation of a pseudo-zero-order catalytic system. The diolate formed is the syn-isomer, which is the kinetically formed product. Direct epoxide fragmentation is the primary source of alkene. This process was determined to be four times faster than ring expansion for cis-stilbene oxide. The synthesis and characterization of a tethered-epoxide Cp* rhenium trioxide complex has been achieved. Reduction of this complex leads to an unsaturated rhenium(V) species that is immediately complexed by the tethered epoxide. Experimental data and molecular mechanics modeling support intramolecular coordination of the epoxide to the rhenium center. These results confirm that the coordinate epoxide is a viable intermediate in rhenium-catalyzed epoxide deoxygenations.
Download or read book Oxygen Transfer Reactions Catalyzed by Rhenium VII and Rhenium V Complexes written by Ruili Huang and published by . This book was released on 2000 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new binuclear oxothiolatorhenium(V) compound, Re2O2(mtp)3 (D1, mtp = 2- mercaptomethylthiophenol), was synthesized by reacting dirhenium(VII) heptoxide (Re2O7) with H2mtp, and characterized spectroscopically and crystallographically. One Re-S bridge in D1 was opened, and sometimes D1 was monomerized, through ligand coordination. D1 was found to be an efficient catalyst for the oxidation of phosphines, triphenylarsine, triphenylantimony, sulfides and dienes by pyridine N-oxides, and unprecedently, by molecular oxygen. D1 also catalyzes the oxidation of phosphines by dimethylsulfoxide. The kinetics and mechanism for the oxidation of triarylphosphines by pyridine N-oxides and 02, as well as the relative reactivities of all substrates, were studied. The reaction was proposed to go through oxorhenium(VII) intermediates. Methyltrioxorhenium (MTO) catalyzes the two-step oxidation of thioketones by hydrogen peroxide to sulfines (thioketone S-oxides) and to ketones releasing sulfur monoxide, which was trapped by a 1,3-diene. The kinetics and mechanism of both steps were studied. The substituted thiobenzophenones were found to attack the peroxo rhenium oxygen nucleophilically.
Download or read book Catalysis with Earth abundant Elements written by Uwe Schneider and published by Royal Society of Chemistry. This book was released on 2020-10-30 with total page 431 pages. Available in PDF, EPUB and Kindle. Book excerpt: Considering the limited resources of our planet, earth-abundant elements will have to be explored increasingly in the future. This book highlights the uses of the most earth-abundant elements in catalysis and will be of interest to graduates, academic researchers and practitioners in catalysis.
Download or read book Catalytic Applications of Rhenium Compounds and Hydrogen Atom Transfer Reactions of Substituted Phthalimide N oxyl Radicals written by Yang Cai and published by . This book was released on 2004 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this work, methyltrioxorhenium (MTO) was found to be an active catalyst for two reactions: one is the reduction of hydronium ions by Eu[Subscript aq]2 to evolve H2; the other is reduction of perchlorate ions to chloride ions by Eu[Subscript aq]2+ or Cr[Subscript aq]2+ in acidic solution. Kinetic studies were carried out and reaction mechanisms were proposed to agree with all the experimental data. In the hydrogen evolution reaction, a rhenium(V) hydride complex was postulated in the scheme to generate H2 by a proton-hydride reaction. Under similar conditions, Cr2+ ions do not evolve H2, despite E0[Subscript Cr][Difference]E0[Subscript Eu]. In addition, no H2 formation was observed in the presence of perchlorate ions because the reaction between methyldioxorhenium (MDO) and perchlorate ions has a much faster rate than that of hydrogen evolution. A six-coordinate rhenium(V) compound MeReO(edt)(bpym) was prepared, characterized, and investigated for oxygen atom transfer reactions between picoline N-oxide and triarylphosphines. We found it is a good catalyst for the reaction, even though it is less active than those five-coordinate rhenium(V) dithiolato compounds. The kinetics showed that the reaction has a first-order dependence on both rhenium and picoline N-oxide. Triarylphosphines were found to inhibit the reaction, and those phosphines with more electron-donating groups in para positions had slower reaction rates. This study proves a hypothesis: there should be a steric requirement for the potential catalyst in the oxygen transfer reactions, which is the necessary existence of an open coordination site on rhenium center. In the last chapter, we studied three different types of reactions of phthalimide N-oxyl radicals (PINO·) and N-hydroxylphthalimide (NHPI) derivatives. First, the self-decomposition of PINO· follows second-order kinetics. However, when excess of 4-Me-NHPI are used in the system, it was found that H-atom abstraction competes with the self-decomposition of 4-Me-PINO·. Second, the hydrogen atom self-exchange reactions between PINO· and substituted NHPI were found to follow H-atom transfer rather than the stepwise electron-proton transfer pathway. Last, the investigations of hydrogen abstraction from para-xylene and toluene by PINO· show large kinetic isotope effects, with the reaction becoming slower when the ring substituent on PINO· is more electron donating.
Download or read book Hydrogen Transfer Reactions written by Gabriela Guillena and published by Springer. This book was released on 2018-06-14 with total page 387 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 Transition Metal Catalyzed Oxidative Cross Coupling Reactions written by Aiwen Lei and published by Springer. This book was released on 2019-02-04 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a comprehensive text covering the research and development trends in the booming field of transition metal catalyzed oxidative cross-coupling reactions. Oxidative cross-coupling reaction is a new method to forming chemical bonds besides the traditional cross-coupling reactions. This book provides the answers to how this coupling reaction occurs and what its advantages are. The palladium, copper and iron catalyzed oxidative cross-coupling reactions as the main focuses of interest are described in detail. The oxidative cross-coupling reactions catalyzed by other metals and transition-metal-free oxidative coupling reactions are also introduced.This book provides a useful reference source for researchers and graduates in the field of transition metal catalyzed coupling reactions. It is also valuable to researchers working in pharmaceutical companies, fine organic chemical companies, and etc.
Download or read book Comprehensive Organic Synthesis written by and published by Newnes. This book was released on 2014-02-14 with total page 9815 pages. Available in PDF, EPUB and Kindle. Book excerpt: The second edition of Comprehensive Organic Synthesis—winner of the 2015 PROSE Award for Multivolume Reference/Science from the Association of American Publishers—builds upon the highly respected first edition in drawing together the new common themes that underlie the many disparate areas of organic chemistry. These themes support effective and efficient synthetic strategies, thus providing a comprehensive overview of this important discipline. Fully revised and updated, this new set forms an essential reference work for all those seeking information on the solution of synthetic problems, whether they are experienced practitioners or chemists whose major interests lie outside organic synthesis. In addition, synthetic chemists requiring the essential facts in new areas, as well as students completely new to the field, will find Comprehensive Organic Synthesis, Second Edition, Nine Volume Set an invaluable source, providing an authoritative overview of core concepts. Winner of the 2015 PROSE Award for Multivolume Reference/Science from the Association of American Publishers Contains more than170 articles across nine volumes, including detailed analysis of core topics such as bonds, oxidation, and reduction Includes more than10,000 schemes and images Fully revised and updated; important growth areas—including combinatorial chemistry, new technological, industrial, and green chemistry developments—are covered extensively
Download or read book Advances in Inorganic Chemistry written by Rudi van Eldik and published by Gulf Professional Publishing. This book was released on 2003-07-08 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Advances in Inorganic Chemistry series presents timely and informative summaries of the current progress in a variety of subject areas within inorganic chemistry ranging from bio-inorganic to solid state studies. This acclaimed serial features reviews written by experts in the area and is an indispensable reference to advanced researchers. Each volume of Advances in Inorganic Chemistry contains an index, and each chapter is fully referenced. This, the 54th volume in the series continues this tradition providing comprehensive reviews by leading experts in the field with the focus on inorganic and bioinorganic reaction mechanisms. The latest volume in this highly successful series is dedicated to inorganic and bioinorganic reaction mechanisms Comprehensive reviews written by leading experts in the field
Download or read book Synthesis Characterization and Reactivity of Rhenium I Tris acetylene and Oxo Bis acetylene Complexes Oxygen Atom Transfer Reactions of Rhenium Triazacyclononane Compounds written by Rebecca Renae Conry and published by . This book was released on 1991 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2003 with total page 860 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Rhenium VII Catalysis of Prins Cyclization Reactions and Synthesis of Tetrahydropyrans Via Intramolecular Hydride Transfer to Oxocarbenium Ions written by Kwanruthai Tadpetch and published by . This book was released on 2010 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Rhenium Catalysis written by Terry G. Selin and published by . This book was released on 1957 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book New Rhenium catalyzed Reactions written by Oscar Esteban Mejía Vargas and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Inorganic Syntheses Volume 36 written by and published by John Wiley & Sons. This book was released on 2014-03-18 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume of Inorganic Syntheses spans the preparations of wide range of important inorganic, organometallic and solid-state compounds. The volume is divided into 6 chapters. The first chapter contains the syntheses of some key early transition metal halide clusters and the very useful mononuclear molybdenum(III) synthon, MoCl3(THF)3. Chapter 2 covers the synthesis of a number of cyclopentadienyl compounds, including a novel route to sodium and potassium cyclopentadienide, MC5H5. Chapter 3 details synthetic procedures for a range of metal-metal bonded compounds, including several with metal-metal multiple bonds. Chapter 4 contains procedures for a range of early and late transition metal compounds, each a useful synthon for further synthetic elaboration. Chapter 5 deals with the synthesis of a number of main group compounds and ligands, while Chapter 6 covers teaching laboratory experiments.
Download or read book Transition Metal Catalysed Reactions written by International Union of Pure and Applied Chemistry and published by . This book was released on 1999 with total page 524 pages. Available in PDF, EPUB and Kindle. Book excerpt:
