The Synthesis and Reactivity of Cycloheptatrienyl Molybdenum and Tungsten Complexes Containing Bisphosphine and Diamine Ligands

The Synthesis and Reactivity of Cycloheptatrienyl Molybdenum and Tungsten Complexes Containing Bisphosphine and Diamine Ligands PDF Author: Salasiah Endud
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Languages : en
Pages : 78

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The Synthesis and Reactivity of Cyloheptatrienyl Molybdenum and Tungsten Complexes Containing Bisphosphine and Diamine Ligands

The Synthesis and Reactivity of Cyloheptatrienyl Molybdenum and Tungsten Complexes Containing Bisphosphine and Diamine Ligands PDF Author: Salasiah Endud
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Category :
Languages : en
Pages : 78

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The Synthesis and Reactivity of Cycloheptatrienyl-nitrile Complexes of Chromium, Molybdenum and Tungsten

The Synthesis and Reactivity of Cycloheptatrienyl-nitrile Complexes of Chromium, Molybdenum and Tungsten PDF Author: Roy Breeze
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Category :
Languages : en
Pages : 131

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Synthesis and Reactivity of Molybdenum and Tungsten Alkylidyne Complexes

Synthesis and Reactivity of Molybdenum and Tungsten Alkylidyne Complexes PDF Author: Laughlin G. McCullough
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Category :
Languages : en
Pages : 282

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Synthesis and Reactivity of Molybdenum and Tungsten Bis-tri-tert-butylsiloxide Imido and Oxo Complexes

Synthesis and Reactivity of Molybdenum and Tungsten Bis-tri-tert-butylsiloxide Imido and Oxo Complexes PDF Author: Devon Charles Rosenfeld
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Category :
Languages : en
Pages : 402

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The Synthesis, Characterization, and Reactivity of Molybdenum and Tungsten - Iron - Sulfur Complexes

The Synthesis, Characterization, and Reactivity of Molybdenum and Tungsten - Iron - Sulfur Complexes PDF Author: Harry Craig Silvis
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Category : Complex compounds
Languages : en
Pages : 340

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The Synthesis, Structure and Reactivity of Cycloheptatrienyl Complexes of Molybdenum Containing [eta]1-bonded Organic Ligands

The Synthesis, Structure and Reactivity of Cycloheptatrienyl Complexes of Molybdenum Containing [eta]1-bonded Organic Ligands PDF Author: Richard Grime
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Category :
Languages : en
Pages : 257

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Synthesis, Reactivity and Electronic Structure of Molybdenum and Tungsten Complexes

Synthesis, Reactivity and Electronic Structure of Molybdenum and Tungsten Complexes PDF Author: Kristine Quinlan
Publisher: Ann Arbor, Mich. : University Microfilms International
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Category :
Languages : en
Pages : 378

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Synthesis and Reactivity of High Oxidation State Tungsten and Molybdenum Olefin Metathesis Catalysts Bearing New Imido Ligands

Synthesis and Reactivity of High Oxidation State Tungsten and Molybdenum Olefin Metathesis Catalysts Bearing New Imido Ligands PDF Author: Jonathan Clayton Axtell
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Category :
Languages : en
Pages :

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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).

The Synthesis, Structure and Reactivity of Cyclootadienyl Complexes of Molybdenum and Tungsten

The Synthesis, Structure and Reactivity of Cyclootadienyl Complexes of Molybdenum and Tungsten PDF Author: Dale Martin Spencer
Publisher:
ISBN:
Category :
Languages : en
Pages : 223

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