Download or read book Synthesis and Reactivity of Cyclopentadienyl Complexes of Tungsten in Its Higher Oxidation States written by Robert Clark Murray and published by . This book was released on 1985 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis and Solid state Reactions of Substituted Cyclopentadienyl Complexes of Rhenium Tungsten and Molybdenum written by Lin Cheng and published by . This book was released on 1997 with total page 476 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis and Reactivity of High Oxidation State Tungsten and Molybdenum Olefin Metathesis Catalysts Bearing New Imido Ligands written by Jonathan Clayton Axtell and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Chapter 1 details the synthesis of tungsten imidoalkylidene compounds bearing strongly electron-withdrawing imido ligands. An alternative synthesis involving the treatment of WCl6 with 4 equivalents of N-trimethylsilyl-substituted anilines and subsequent workup with 1,2-dimethoxyethane (DME) has been employed to form complexes of the type W(NAr)2C12(dme); syntheses employing WO2C 2(dme) as the tungsten precursor were unsuccessful. Alkylation with neopentylmagnesium chloride (ClMgNp) and subsequent treatment with trifluoromethanesulfonic acid (HOTf) affords imidoalkylidene species W(NAr)(CHCMe 3)(OTf)2(dme) (OTf = trifluoromethanesulfonate); analogous neophylidene ([W]CHCMe 2Ph) species could not be made under these conditions. Treatment of these compounds with two equivalents of LiO(2,6-(CHCPh 2)C6H3)-Et2O affords the bisaryloxide complexes of the type W(NAr)(CHCMe3)(OR)2. Ring-Opening Metathesis Polymerization (ROMP) studies using a series of these bisaryloxides show that rates of ROMP increase as the electron-withdrawing power of the substituents on the imido ligand increase if steric bulk about the metal center is held constant. A similar trend between two bisaryloxides is observed for anti-to-syn alkylidene rotation rates at 50*C in toluene-d8 . Difficulties synthesizing bis-pyrrolide complexes of the type W(NAr)(CHCMe3)(pyr)2 precluded their use as catalyst precursors; some MAP species containing the more sterically encumbering 2,5-dimethylpyrrolide ligand are presented and the metathesis activity of MAP species bearing the 2,5-dimethylpyrrolide ligand is discussed. Chapter 2 introduces Mo and W complexes bearing the current extreme in sterically bulky imido ligands, the NHIPT (HIPT = 2,6-(2,4,6-iPr 3CH2)CH3) ligand, in an effort to generate all anti alkylidene species. A non-traditional synthetic route is employed in order to install this ligand first as an anilide, and after subsequent proton transfer, as an imido ligand to form a mixed imido species of the type M(NHIPT)(N'Bu)(NH'Bu)Cl. Addition of one equivalent of 2,6-lutidinium chloride, followed by alkylation affords dialkyl species M(NHIPT)(N'Bu)Np 2, and treatment with three equivalents of pyridinium chloride yields all anti imidoalkylidene dichloride species as mono-pyridine adducts, M(NHIPT)(CHCMe 3)C 2(py) (M = Mo, W). General reactivity, including strategies for removal of the pyridine adduct as well as substitution and metathesis chemistry, are discussed. ROMP of MPCP (MPCP = 3-methyl-3-phenylcyclopropene) by a Mo-based MAP species bearing the NHIPT ligand yields predominantly cis,syndiotactic poly(MPCP) and in the homo-metathesis of 1 -octene yields ~81% cis-7-tetradecene. The possible source of trans olefinic product is addressed. Chapter 3 presents the synthesis of the first (1-adamantyl)imido species of tungsten. The functional equivalent of common bisimido precursors for other Mo/W alkylidene species, [W(NAd) 2C 2(AdNH2)1 2, is shown to be a dimer stabilized by hydrogen-bonding interactions between adamantylamine protons and adjacent chlorides bound to the second metal of the dimer. Subsequent alkylation with ClMgNp affords the expected dialkyl species, and treatment with three equivalents of 3,5-lutidinium chloride affords imidoalkylidene complex W(NAd)(CHCMe 3)(C) 2(lut)2 (lut = 3,5-dimethylpyridine). The most desirable synthetic route toward monoalkoxide pyrrolide (MAP) species proceeds through a monoaryloxide monochloride intermediate W(NAd)(CHCMe 3)(Cl)(OAr)(lut) (Ar = 2,6-(2,4,6-Me 3)C6H3, 2,6-(2,4,6-'Pr 3)C6H3). Removal of lutidine with B(C6 F5 )3 and subsequent treatment with lithium pyrrolide affords W(NAd)(CHCMe3)(pyr)(OAr) (pyr = pyrrolide); 2,5-dimethylpyrrolide analogues (W(NAd)(CHCMe3)(Me2pyr)(OAr) can be accessed via protonolysis by HOAr from W(NAd)(CHCMe3)(Me2pyr)2(lut).

Download or read book Halfsandwich Tungsten Complexes with a Silanol functionalized Cyclopentadienyl Ligand written by Holger Bera and published by . This book was released on 2005 with total page 329 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis Characterization and Reactivity of Novel Dinitrosyl Tungsten Complexes in Various Oxidation States written by Javier Fraga-Hernández and published by . This book was released on 2007 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Novel Strategies for the Synthesis of Tungsten VI and Molybdenum VI Imido Oxo Alkylidene NHC Complexes and Their Application in Ring Opening Metathesis Polymerization written by Janis Musso and published by Cuvillier Verlag. This book was released on 2022-05-12 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recently, the synthesis of neutral and cationic group(VI) imido/oxo alkylidene N-heterocyclic carbene (NHC) complexes that tolerate protic functional groups and aldehydes was reported. Unprecedented turnover numbers of up to 1.2 million were found for their silica-supported representatives. Some group(VI) alkylidene NHC complexes even display stability towards moisture and air. Coordination of the NHC to tungsten imido bistriflate precursor complexes, however, can lead to undesired side reactions. This work consequently aimed at the development of novel, more efficient routes to neutral and cationic tungsten imido/oxo alkylidene NHC complexes. In addition, some molybdenum imido alkylidene NHC complexes were targeted. Thereby, the scope of synthetically accessible complexes was broadened and, subsequently, their reactivity in ring-opening metathesis polymerization (ROMP) was probed. Those complexes were used as thermally latent initiators for the ROMP of dicyclopentadiene. Precise determination of the onset temperature of polymerization was achieved via monitoring with differential scanning calorimetry. Furthermore, the selectivity of novel complexes was tested for the formation of stereoregular polymers through ROMP of enantiomerically pure norbornene derivatives, which allowed for the synthesis of up to 98% trans-isotactic or cis-syndiotactic polymers depending on the steric demand of the imido and the alkoxide ligand.

Download or read book American Doctoral Dissertations written by and published by . This book was released on 1996 with total page 872 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis and Reactivity of Transition Metal Complexes Containing Pentamercurated Cyclopentadienyl Ligands written by Young Hee Han and published by . This book was released on 1993 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Synthesis and Reactivity of Tungsten VI Alkylidynes and Tungsten IV Complexes written by Mark L. Listemann and published by . This book was released on 1985 with total page 342 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 Synthesis and Reactivity of Titanium and Tungsten Diolate Complexes written by Denise L. Barnes and published by . This book was released on 1993 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Synthesis and Reactivity of Methylidyne and Hydride Complexes of Tungsten written by Steven J. Holmes and published by . This book was released on 1983 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Preparation and Characterization of High Oxidation State Tungsten and Molybdenum Complexes Containing Phenoxide Thiolate Alkyl Cyclopentadienyl and Dinitrogen Ligands written by Richard Michael Kolodziej and published by . This book was released on 1989 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Chemistry of High Oxidation State Monopentamethyl cyclopentadienyl Tungsten and Molybdenum Complexes written by Andy Hen Liu and published by . This book was released on 1988 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Transition Metal Carbyne Complexes written by F.R. Kreißl and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt: The chemistry of transition metal carbyne complexes has become a highly attractive field during the past twenty years. In recent years its application to aspects of catalysis and metathesis has gained considerable interest from inorganic as well as organic chemists. In addition, organic synthesis by means of metal carbon multiple bond reagents offers the most sophisticated technology currently available. In consideration of these developments some of Professor E. O. Fischer's former coworkers and colleagues felt obliged to orga nize this NATO Advanced Research Workshop on Transition Metal Carbyne Complexes in the Bavarian Alps. They have been encouraged by the fact that most of the distinguished scientists in the field of metal-carbon multiple bond chemistry had finally agreed to participate and to present stimulating lectures. The organizers of the workshop are deeply grateful to the Scientific Affairs Division of the NATO for the generous financial support of the meeting in Wildbad Kreuth and for the preparation of this book. They also feel indebted to acknowledge the generous support from Wacker-Chemie, BASF, Peroxid-Chemie, Hoechst and Bayer. Finally they thank the staff of the Hanns-Seidel-Stiftung in Wildbad Kreuth for providing a pleasant and stimu lating atmosphere during the meeting.

Download or read book Comprehensive Dissertation Index written by and published by . This book was released on 1989 with total page 712 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis and Reactivity of Tungsten VI Alkylidene and Metallacyclobutane Complexes written by Jerald Feldman and published by . This book was released on 1989 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt: