Download or read book Alkyne and Imido Molybdenum Complexes and Their Relationship to Nitrogenase written by Eric Arn Maata and published by . This book was released on 1980 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Spectroscopic Studies of Molybdenum Complexes as Models for Nitrogenase written by and published by . This book was released on 1981 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Because biological nitrogen fixation requires Mo, there is an interest in inorganic Mo complexes which mimic the reactions of nitrogen-fixing enzymes. Two such complexes are the dimer Mo2O4 (cysteine)2/sup 2 -/ and trans-Mo(N2)2(dppe)2 (dppe = 1,2-bis(diphenylphosphino)ethane). The H1 and C13 NMR of solutions of Mo2O4(cys)2/sup 2 -/ are described. It is shown that in aqueous solution the cysteine ligands assume at least three distinct configurations. A step-wise dissociation of the cysteine ligand is proposed to explain the data. The Extended X-ray Absorption Fine Structure (EXAFS) of trans-Mo(N2)2(dppe)2 is described and compared to the EXAFS of MoH4(dppe)2. The spectra are fitted to amplitude and phase parameters developed at Bell Laboratories. On the basis of this analysis, one can determine (1) that the dinitrogen complex contains nitrogen and the hydride complex does not and (2) the correct Mo-N distance. This is significant because the Mo inn both complexes is coordinated by four P atoms which dominate the EXAFS. A similar sort of interference is present in nitrogenase due to S coordination of the Mo in the enzyme. This model experiment indicates that, given adequate signal to noise ratios, the presence or absence of dinitrogen coordination to Mo in the enzyme may be determined by EXAFS using existing data analysis techniques. A new reaction between Mo2O4(cys)2/sup 2 -/ and acetylene is described to the extent it is presently understood. A strong EPR signal is observed, suggesting the production of stable Mo(V) monomers. EXAFS studies support this suggestion. The Mo K-edge is described. The edge data suggests Mo(VI) is also produced in the reaction. Ultraviolet spectra suggest that cysteine is released in the course of the reaction.
Download or read book Molybdenum Complexes as Models of Nitrogenase written by Michael A. Jackson and published by . This book was released on 1988 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nitrido and Imido complexes of Molybdenum V written by Mark E. Noble and published by . This book was released on 1982 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book American Doctoral Dissertations written by and published by . This book was released on 1993 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Comprehensive Dissertation Index written by and published by . This book was released on 1984 with total page 992 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ligand Variation in Molybdenum Imido Alkylidene Complexes written by Alejandro Gaston Lichtscheidl and published by . This book was released on 2012 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chapter 1. A general introduction is given. Chapter 2. The biscarboxylate species, Mo(NR)(CHCMe 2Ph)(O 2CPh3)2 (R = 2,6-i-Pr2C6H3, 2,6- Me2C6H3, 2-t-BuC 6H4, or 1 -adamantyl) are compared to newly synthesized bis(terphenylcarboxylate) species, Mo(NR)(CHCMe 2Ph)(O 2CTer)2 (Ter = 2,6-diphenyl-4- methylphenyl or 2,6-diphenyl-4-methoxyphenyl). Preparation of bis(terphenylcarboxylate) species was accomplished through protonolysis of Mo(NR)(CHCMe2R')(Me2Pyr)2 with two equivalents of TerCO2H and one of them was characterized through X-ray crystallography. Photolysis experiments of many of the biscarboxylate complexes led to rate constants for the converstion of anti to syn species, which are much slower than bisalkoxide species. Trimethylphosphine adducts of selected triphenylacetate complexes have been isolated and studied in solution. Protonolysis of Mo(NAr)(CHCMe 2R')(Me 2Pyr)2 (Ar = 2,6-i-Pr 2C6H3) with one equivalent of TerCO2H led to the isolation of a handful of monocarboxylate species, Mo(NAr)(CHCMe 2Ph)(O 2CAr')(Me2Pyr). An X-ray structure of one of them was also characterized. Several of the bis(triphenylacetate) complexes and all of the monocarboxylates are active initiators for the regioselective polymerization of diethyl dipropargylmalonate (DEPDM). In the case of the latter compounds, activity towards olefins is also observed and briefly mentioned.
Download or read book The Synthesis and Reactions of Molybdenum II and Tungsten II Alkyne Complexes written by Elaine M. Armstrong and published by . This book was released on 1989 with total page 710 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Redox Chemistry of Molybdenum and Tungsten Alkyne Complexes written by Elena Patrkon-Rodrkiguez and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High Oxidation State Molybdenum and Tungsten Imido Alkylidene and Metallacycle Chemistry written by W. C. Peter Tsang and published by . This book was released on 2004 with total page 526 pages. Available in PDF, EPUB and Kindle. Book excerpt: (Cont.) unsubstituted tungstacyclobutane complexes (82), ethylene complexes (84), tungstacyclopentane complexes (86), and a heterochiral methylene dimer (85a). The tungstacyclopentane complexes catalyzed slow dimerization of ethylene to 1-butene. The observation of the methylene dimer provides the first direct evidence of a bimolecular decomposition pathway for methylene complexes. Chapter 3 Racemic and enantiomerically pure molybdenum alkylimido alkylidene complexes, Mo(NAd)(CHCMe2Ph)(Biphen) (19d, Ad = 1-adamantyl) and Mo(NAd)(CHCMe2Ph)[Trip]-(THF) (20d) were prepared and structurally characterized. Complex 19d was observed almost exclusively as a syn alkylidene isomer, in contrast with 20d which was observed almost exclusively as an anti-THF adduct. Complexes 19d and 20d are the only reported chiral alkylimido alkylidene complexes for enantioselective olefin metathesis reactions. Complex 19d is the first crystallographically characterized four-coordinate adamantylimido alkylidene complex in its base-free form. It offers unique reactivity and selectivity profiles in tandem AROM/RCM and AROM/CM reactions. Complex 19d is compatible with a variety of common functional groups, including boron-containing reagents. Van't Hoff analyses suggest that the bias toward syn-19d isomer is entropy-driven. Chapter 4: Solvent- and base-free molybdenum methylene complexes, Mo(NAr)(Biphen)(CH2) (114a, Ar = 2,6-i-Pr2C6H3) and Mo(NAd)(Biphen)(CH2) (114d, Ad = 1-adamantyl) ...
Download or read book Dissertation Abstracts International written by and published by . This book was released on 1981 with total page 572 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Spectroscopic Studies of Molybdenum Complexes as Models for Nitrogenase written by Timothy Paar Walker and published by . This book was released on 1981 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Transition Metal Dinitrogen Complexes written by Yoshiaki Nishibayashi and published by John Wiley & Sons. This book was released on 2019-05-06 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive book that explores nitrogen fixation by using transition metal-dinitrogen complexes Nitrogen fixation is one of the most prominent fields of research in chemistry. This book puts the focus on the development of catalytic ammonia formation from nitrogen gas under ambient reaction conditions that has been recently repowered by some research groups. With contributions from noted experts in the field, Transition Metal-Dinitrogen Complexes offers an important guide and comprehensive resource to the most recent research and developments on the topic of nitrogen fixation by using transition metal-dinitrogen. The book is filled with the information needed to understand the synthesis of transition metal-dinitrogen complexes and their reactivity. This important book: -Offers a resource for understanding nitrogen fixation chemistry that is essential for explosives, pharmaceuticals, dyes, and all forms of life -Includes the information needed for anyone interested in the field of nitrogen fixation by using transition metal-dinitrogen complexes -Contains state-of-the-art research on synthesis of transition metal-dinitrogen complexes and their reactivity in nitrogen fixation -Incorporates contributions from well-known specialists and experts with an editor who is an innovator in the field of dinitrogen chemistry Written for chemists and scientists with an interest in nitrogen fixation, Transition Metal-Dinitrogen Complexes is a must-have resource to the burgeoning field of nitrogen fixation by using transition metal-dinitrogen complexes.
Download or read book Comprehensive Dissertation Index written by University Microfilms International and published by Ann Arbor, Mich. : University Microfilms International. This book was released on 1984 with total page 712 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Approaches Toward the Synthesis of New Molybdenum Complexes as Models for the Active Site in Nitrogenase Enzymes written by Jessica Hilborn and published by . This book was released on 2005 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Chemistry of Molybdenum Complexes with Sulfur coordinated Or Tolylimidochlorides Environments written by Yang ching Chou and published by . This book was released on 1986 with total page 332 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Aspects of the Reactivity of Mononuclear Molybdenum Complexes Containing an Alkyne Ligand written by Christopher M. Woolhouse and published by . This book was released on 1989 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
