Download or read book Molybdenum IV Imido Silylamido and Hydride Complexes written by Andrey Y. Khalimon 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 Preparation and Reaction of the Thiolate Hybride Complexes of Molybdenum written by and published by . This book was released on 1996 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes studies on the synthesis and reactivity of a variety ofmolybdenum thiolate hydride complexes; tungsten complexes were also prepared forcomparison. The original purpose of this research was to examine the behaviour of sulphurligatedmolybdenum complexes as models for the molybdenum site in nitrogenase, but thiswork has demonstrated that the 5-coordinated complexes [MoH(SC6H2R3-2,4,6)3(PR1Ph2)] (R= Me or Pr'; R1 = Me or Et) are very reactive versatile starting materials for thepreparation of a wide range of derivatives, some of which model aspects of the chemistry ofother molybdenum enzymes such as xanthine oxidase.It is known that the reaction of thiols HSC6H2R3-2,4,6 with [MoH4(PR'Ph2)4] or trans-[Mo(N2)2(PMePh2)4] produces unsaturated thiolato-hydride complexes of molybdenum(IV)[MoH(tipt)3(PMePh2)] (A) (tipt = SC6H2PrV-2,4,6). Here we report an extension of thesestudies in which we have prepared the oxygen-sensitive, five- and six-coordinated complexes[MoH(SC6H4F)3(PMePh2)] (2.3) and [MoH(SC6HF4-2,3,5,6)3(PMePh2)2] (2.1) and[MoH(SC6F5)3(PMePh2)2] (2.4).Some reactions of (2.3), (2.1) and (2.4) have been investigated, including the reactionof (2.4) with carbon monoxide which yields [Mo(SC6F5)2(CO)2(PMePh2)2] (6.7). Thereaction of (2.1) with pyridine gives [MoH(SC6HF4-2,3,5,6)3(C5H5N)(PMePh2)] (6.1).The reaction of the electron-deficient hydride thiolate complex [MoH(tipt)3(PMe2Ph)2](B) with phenylacetylene gives the novel square pyramidal, diamagnetic phosphoniumalkylidenecomplex[MoO{=C(Ph)CH=C(Ph)CH2PMe2Ph)(SC6H2Pri3-2,4,6)3](3E), whereasthe reaction of /Molylacetylene with (A) yields the novel phosphonium ylide complex[MoO(SC6H2Pri3)2(HC=CC6H4Me-4){(C6H4Me-4) (C=CHPMePh2)}](3D),thathas relevanceto the species derived from xanthine oxidase when it is inhibited by aldehydes. These twocomplexes have been characterised by X-ray structure determination. [WH(tipt)3(PMe2Ph)2j(C) with phenylacetylene and p-tolylacetylene gives products resulting from oligomerisationreactions.In the reaction o f [MoH(tipt)3(PMePh2)] (A) with hydrazines, both binding of hydrazineto Mo and disproportionation/reduction have been observed. The bright green andtemperature- and oxygen-sensitive complex [MoH(tipt)3(NH3)(PMePh2)J (4.1) has beenobtained from the reaction of NH2NH2 with (A). Its X-ray structure determination at -10°Cshows that it is a hydride ammonia complex with trigonal bipyramidal geometry. Thereaction of phenylhydrazine with (A) gives dark green single crystals that have been thesubject of an X-ray crystallographic analysis. This compound crystallised in a much-distortedtrigonal bipyramidal geometry and is formulated as [MoH(tipt)3(NH2NHPh)(PMePh2)] (4.4).Isocyanides are substrates or inhibitors of nitrogenase. The interaction of isocyanides withthe five- and six-coordinate hydride complexes has been investigated. The reaction of[MoH(tipt)3(PMePh2)] (A) with MeNC and t-BuNC and also the reaction of[WH(tipt)3(PMe2Ph)2] (C) with MeNC, produce [MoH(tipt)2(MeNC)4] (5.1), [MoH(tipt)2('-BuNC)4] (5.3) and [WH(tipt)2(MeNC)4] (5.2) respectively. The structures of these complexeshave been confirmed by X-ray structure determination.The reaction of molybdenum hydride complexes with carboxylic acids give productswhich show carboxylate groups in their IR and NMR spectra.
Download or read book Imido Complexes of Molybdenum and Osmium written by Jennifer Robbins Wolf and published by . This book was released on 1993 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Molybdenum written by Eric Reeves Braithwaite and published by Elsevier Science & Technology. This book was released on 1994 with total page 688 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hardbound. Molybdenum is an element with an extremely rich and interesting chemistry having very versatile applications in various fields of human activity. It is used extensively in metallurgical applications. Because of their anti-wear properties, molybdenum compounds find wide applications as lubricants - particularly in extreme or hostile environmental situations. Many molybdates and heteropolymolybdates are white and therefore used as pigments. In addition, they are non-toxic and act as efficient corrosion inhibitors and smoke suppressants. Hydroprocessing of petroleum is one of the largest industries employing heterogeneous catalysts. Molybdenum catalysts have shown great promise in the liquefaction of coal and this may develop into one of its most important catalytic uses. The use of molybdenum compounds in homogeneous catalysis is also significant.Three important classes of molybdenum compounds in the solid state are reviewed, viz., oxides, sul
Download or read book Synthesis and Reactivity of Molybdenum and Tungsten Bis tri tert butylsiloxide Imido and Oxo Complexes written by Devon Charles Rosenfeld and published by . This book was released on 2005 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 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 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 Synthesis and Reactivity of Molybdenum Organometallic Complexes Supported by Amide Ligands written by Adam Scott Hock and published by . This book was released on 2007 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt: (Cont.) Chapter 4. Reactivity of Molybdenum Imido Alkylidene Bis(pyrrolyl) Complexes. The Lewis amphoteric nature of the bis(pyrrolyl) complexes reported in chapter 3 is examined by demonstrating that these complexes react with both trimethylphosphine (at the molybdenum center) and B(C6Fs)3 (at a q5 pyrrolyl nitrogen). A structure of a trimethylphosphine adduct is reported. The bis(pyrrolyl) complexes are found to serve as excellent precursors for the in situ generation of olefin metathesis catalysts at room temperature and millimolar concentration. Furthermore, catalysts not accessible via traditional routes may now be accessed from bis(pyrrolyl) precursors. The bis(pyrrolyl) complexes also react with simple olefins such as ethylene and isobutylene to yield what are proposed to be a bimetallic dimer [Mo(NAr)(NC4H4)2]2 and a 2-propylidene complex via olefin metathesis. The impact of in situ synthesis on syn and anti isomer ratios is discussed as is reactivity with protic reagents other than alcohols.
Download or read book Chiral Molybdenum and Tungsten Imido Alkylidene Complexes as Catalysts for Asymmetric Ring closing Metathesis ARCM written by John Bryson Alexander and published by . This book was released on 1999 with total page 360 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 Preparation Properties and Reactions of Complexes of Molybdenum III IV and V written by Rodney Desmond Scarle and published by . This book was released on 1974 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thiolato hydride Complexes of Molybdenum written by M. J. Maguire and published by . This book was released on 1993 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Preparation and Reaction of the Thiolate Hydride Complexes of Molybdenum written by Katayoun Marjani and published by . This book was released on 1996 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dinitrogen and Hydride Complexes of Molybdenum with Phosphorus and Sulfur donor Coligands written by Natalie Joan Lazarowych and published by . This book was released on 1989 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Chemistry of Organoimido Complexes of Molybdenum and Vanadium written by David D. Devore and published by . This book was released on 1987 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Comprehensive Organometallic Chemistry III Volume 5 written by D. M. P. Mingos and published by . This book was released on 2007 with total page 1008 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides essential information for any chemist or technologist who needs to use or apply organometallic compounds. Provides a comprehensive overview of recent developments in the field and attempts to predict trends in the field over the next ten years.
