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 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 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 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 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 Preparation and Reactivity of High Oxidation State Pentamethylcyclopentadienyl Complexes of Tungsten for Activation of Dinitrogen written by Marie Bernadette O'Regan and published by . This book was released on 1991 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Lanthanides Series Determination by Various Analytical Methods written by Mohammad Reza Ganjali and published by Elsevier. This book was released on 2016-02-25 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lanthanides Series Determination by Various Analytical Methods describes the different spectroscopic and electrochemical methods used for the determination and measurement of lanthanides. Numerous examples of determination methods used in real sample analysis are gathered and explained, and the importance of lanthanides as applied in chemical industry, agriculture, clinical and pharmaceutical industry, and biology is discussed, with many applications and recent advantages given. Written by world-leading experts in research on lanthanide determination Discusses determination methods that range from very advanced and expensive techniques to simple and inexpensive methods A single source of information for a broad collection of lanthanide detection techniques and applications Includes a complete list of reports and patents on lanthanide determination Discusses both advantages and disadvantages of each determination method, giving a well-balanced overview

Download or read book Modern Aspects of Rare Earths and their Complexes written by Vinny R. Sastri and published by Elsevier. This book was released on 2003-12-09 with total page 1005 pages. Available in PDF, EPUB and Kindle. Book excerpt: In order to use rare earths successfully in various applications, a good understanding of the chemistry of these elements is of paramount importance. Nearly three to four decades have passed since titles such as The Rare Earths edited by F.H. Spedding and A.H. Daane, The chemistry of the Rare Earth Elements by N.E. Topp and Complexes of the Rare Earths by S.P. Sinha were published. There have been many international conferences and symposia on rare earths, as well as the series of volumes entitled Handbook of Physics and Chemistry of Rare Earths edited by K.A. Gschneidner and L. Eyring. Thus, there is a need for a new title covering modern aspects of rare earth complexes along with the applications. The present title consists of twelve chapters. 1. Introduction2. General aspects3. Stability of complexes4. Lanthanide complexes5. Structural chemistry of lanthanide compounds6. Organometallic complexes7. Kinetics and mechanisms of rare earths complexation8. Spectroscopy of lanthanide complexes9. Photoelectron spectroscopy of rare earths10. Lanthanide NMR shift reagents11. Environmental ecological biological aspects12. Applications The authors studied in schools headed by pioneers in rare earth chemistry, have a combined experience of one hundred and fifty years in inorganic chemistry, rare earth complex chemistry, nuclear and radiochemistry of rare earths and supramolecular chemistry. The present monograph is a product of this rich experience.

Download or read book Rare Earth Based Corrosion Inhibitors written by Maria Forsyth and published by Elsevier. This book was released on 2014-08-12 with total page 347 pages. Available in PDF, EPUB and Kindle. Book excerpt: Corrosion inhibitors are an important method for minimizing corrosion; however traditional inhibitors such as chromates pose environmental problems. Rare earth metals provide an important, environmentally-friendly alternative. This book provides a comprehensive review of current research and examines how rare earth metals can be used to prevent corrosion and applied to protect metals in such industries as aerospace and construction. Chapter 1 begins by examining the important need to replace chromate, and then goes on to discuss the chemistry of the rare earth metals and their related compounds. Chapter 2 considers the techniques that can be used to identify corrosion inhibition mechanisms and to test the levels of protection offered to different metals by rare earth compounds. Subsequent chapters consider in more detail how rare earth elements can be used as corrosion inhibitors in different forms and for different metals. This includes discussion on the potential of rare earth elements for self-healing, tunable and multifunctional coatings. Finally, chapter 10 considers the cost and availability of the rare earths and the potential health and environmental risks associated with extracting them. Provides a review of current research and examines how rare earth metals can be used to prevent corrosion and applied to protect metals in such industries as aerospace and construction Includes discussion on the potential of rare earth elements for self-healing, tunable and multifunctional coatings Considers the cost and availability of the rare earths and the potential health and environmental risks associated with extracting them

Download or read book Energy Materials written by Sanjay J. Dhoble and published by Elsevier. This book was released on 2021-08-15 with total page 630 pages. Available in PDF, EPUB and Kindle. Book excerpt: Includes details of the fundamental phenomenological theories of solar cells, Li ion/ Li-air/Li-S batteries, fuel cells and their energy storage mechanisms. Discusses properties of various energy materials in addition to their device operation and evaluation. Includes details of the fundamental phenomenological theories of solar cells, Li ion/ Li-air/Li-S batteries, fuel cells and their energy storage mechanisms Discusses properties of various energy materials in addition to their device operation and evaluation

Download or read book Membrane Based Separations in Metallurgy written by Lan Ying Jiang and published by Elsevier. This book was released on 2017-03-20 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Membrane-Based Separation in Metallurgy: Principles and Applications begins with basic coverage of the basic principles of the topic and then explains how membrane technology helps in the development of new environmentally friendly and sustainable metallurgical processes. The book features the principles of metallurgical process and how widely the membrane-based technology has been applied in metallurgical industry, including the basic principles of membrane-based separation in terms of material science, membrane structure engineering, transport mechanisms, and module design, detailed metallurgical process flowcharts with emphasis on membrane separations, current process designs, and describes problems and provides possible solutions. In addition, the book includes specific membrane applications, molecular design of materials, fine tuning of membrane's multi-scale structure, module selection and process design, along with a final analysis of the environmental and economic benefits achieved by using these new processes.