Download or read book Molybdenum and Tungsten Compounds in Oxidation Catalysis written by Alexander Raith and published by . This book was released on 2011 with total page 195 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Molybdenum and Tungsten Enzymes written by Russ Hille and published by Royal Society of Chemistry. This book was released on 2016-09-30 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: There has been enormous progress in our understanding of molybdenum and tungsten enzymes and relevant inorganic complexes of molybdenum and tungsten over the past twenty years. This set of three books provides a timely and comprehensive overview of the field and documents the latest research. Building on the first and second volumes that focussed on biochemistry and bioinorganic chemistry aspects, the third volume focusses on spectroscopic and computational methods that have been applied to both enzymes and model compounds. A particular emphasis is placed on how these important studies have been used to reveal critical components of enzyme mechanisms.This text will be a valuable reference to workers both inside and outside the field, including graduate students and young investigators interested in developing new research programs in this area.

Download or read book Molybdenum and Tungsten Cofactor Model Chemistry written by Carola Schulzke and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Molybdenum is crucially important for almost all organisms ranging from ancient single cell micro-organisms to modern human beings. The reactions catalyzed by molybdenum and tungsten co-factors involve two electron oxidation or reduction usually accompanied by an oxygen atom transfer from water to substrate or vice versa as part of the carbon, nitrogen and sulphur metabolism. This book deals with the advances of molybdenum and tungsten co-factor model chemistry including a brief survey of the earlier stages of even older inorganic dithiolene chemistry.

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 Transition Metals in Catalysis written by Silke Leimkühler and published by MDPI. This book was released on 2021-03-10 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: Iron–sulfur (FeS) centers are essential protein cofactors in all forms of life. They are involved in many key biological processes. In particular, Fe-S centers not only serve as enzyme cofactors in catalysis and electron transfer, they are also indispensable for the biosynthesis of complex metal-containing cofactors. Among these cofactors are the molybdenum (Moco) and tungsten (Wco) cofactors. Both Moco/Wco biosynthesis and Fe-S cluster assembly are highly conserved among all kingdoms of life. After formation, Fe-S clusters are transferred to carrier proteins, which insert them into recipient apo-proteins. Moco/Wco cofactors are composed of a tricyclic pterin compound, with the metal coordinated to its unique dithiolene group. Moco/Wco biosynthesis starts with an Fe-S cluster-dependent step involving radical/S-adenosylmethionine (SAM) chemistry. The current lack of knowledge of the connection of the assembly/biosynthesis of complex metal-containing cofactors is due to the sheer complexity of their synthesis with regard to both the (genetic) regulation and (chemical) metal center assembly. Studies on these metal-cofactors/cofactor-containing enzymes are important for understanding fundamental cellular processes. They will also provide a comprehensive view of the complex biosynthesis and the catalytic mechanism of metalloenzymes that underlie metal-related human diseases.

Download or read book Noble Metals Molybdenum and Tungsten in Hydrocarbon Synthesis written by John Floid Shultz and published by . This book was released on 1967 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Study of the Properties of Molybdenum Compounds for the Catalytic Oxidation of Logistic Fuels written by Oscar Gerardo Marin-Flores and published by . This book was released on 2009 with total page 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 Tungsten and Molybdenum written by Curt Agte and published by . This book was released on 1963 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Studies of Supported Molybdenum and Tungsten Progress Report written by and published by . This book was released on 1993 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: Work on Mo oxidation state-catalytic activity relations has centered around measuring the distribution of Mo oxidation states on reduced Mo/alumina and Mo/titania catalysts, and correlating catalyst activity with Mo oxidation states. Factor analysis has been developed as a protocol for measuring Mo oxidation state distributions on reduced catalysts. Papers published and submitted are discussed.

Download or read book Synthesis and Studies of Mo and W Complexes for 2N Reduction written by Jia Min Chin and published by . This book was released on 2010 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: A series of monopyrroletriamine ligands [Arpyr(Ar')2]H3 of the form ArC4H2NHCH2N(CH2CH2NHAr')2 (Ar = 2,4,6-mesityl (Mes), 2,4,6-triisopropylphenyl (TRIP); Ar' = C6F5, 2-tolyl (o-tol), naphthyl, 3,5-(2,4,6-triisopropylphenyl)phenyl (HIPT), 3,5- dimethylphenyl, 3,5-di-tert-butylphenyl were synthesized. [Mespyr(C6F5)2]MoCl, ([Mespyr(C6F5)2]Mo = MesitylC4H2NCH2N(CH2CH2NC6F5)2) was prepared by reaction of [Mespyr(C6F5)2]H3 with MoCl4(THF)2 and base and [Mespyr(3,5-t-Bu)2]MoCl and [Mespyr(3,5- Me)2]MoCl (3,5-t-Bu=3,5-di-tert-butylphenyl, Me = 3,5-dimethylphenyl) were synthesized likewise. All three monochlorides are paramagnetic. [Mespyr(C6F5)2]MoNMe2, [[Mespyr(otol) 2]MoNMe2, [Mespyr(3,5-t-Bu)2]MoNMe2, [Mespyr(3,5-Me)2]MoNMe2 were synthesized by reaction of the ligands with Mo(NMe2)4. The resulting compounds are diamagnetic and range in color from teal blue to emerald green. These low spin monodimethylamide complexes exist in rapid equilibria with their high spin forms. [Mespyr(C6F5)2]MoN and [Mespyr(3,5-t-Bu)2]MoN were synthesized by reaction of their respective monochlorides with NaN3 and are yellow diamagnetic species. Reaction of [Mespyr(3,5-t-Bu)2]MoN with Et3OBF4 leads to {[Mespyr(3,5- t-Bu)2]MoNEt}BF4, also a diamagnetic yellow species. [Mespyr(C6F5)2]MoOTf is synthesized by the reaction of [Mespyr(C6F5)2]MoCl with AgOTf. Reduction of [Mespyr(3,5-t-Bu)2]MoCl with Na under N2 led to [Mespyr(3,5-t-Bu)2]MoNNNa(THF)x, several species with varying numbers of THF coordination, x. A single species can be obtained when [Mespyr(3,5-t- Bu)2]MoNNNa(THF)x is reacted with either NBu4Cl or 15-crown-5 ether to yield purple green 4 {[Mespyr(3,5-t-Bu)2]MoNN}NBu4 or [Mespyr(3,5-t-Bu)2]MoNNNa(15-c-5). All the diazenide species are diamagnetic. Oxidation of the diazenide with AgOTf yields [Mespyr(3,5-t- Bu)2]Mo(N2). [Mespyr(3,5-t-Bu)2]Mo(CO) is synthesized by exposure of [Mespyr(3,5-t- Bu)2]Mo(N2) to CO. Reaction of [Mespyr(3,5-t-Bu)2]MoCl with NaBPh4 and NH3 yields {[Mespyr(3,5-t-Bu)2]Mo(NH3)}BPh4. Catalytic runs employing [Mespyr(3,5-t-Bu)2]MoN as the catalyst yielded one equivalent of NH3. A triamidoamine ligand [(HIPTNCH2CH2CH2)3N]3- was synthesized and metalated with MoCl4(THF)2 to produce [(HIPTNCH2CH2CH2)3N]MoCl ([HIPTtrpn]MoCl). Reduction of [HIPTtrpn]MoCl by KC8 under an atmosphere of dinitrogen leads to the green species [HIPTtrpn]MoNNK which can be oxidized by ZnCl2(dioxane) to produce [HIPTtrpn]Mo(N2). Other complexes synthesized include {[HIPTtrpn]Mo(NH3)}+ salts and [HIPTtrpn]Mo(CO). Xray studies were carried out on [HIPTtrpn]MoN and {[HIPTtrpn]Mo(NH3)}BAr'4. This system is not catalytic for the reduction of dinitrogen to ammonia and studies were carried out to elucidate the reasons. Oxidation studies were carried out on [HIPTN3N]Mo(N2) and [HIPTN3N]W(N2) ([HIPTN3N] = [(HIPTNCH2CH2)3N]3- ). The rate of conversion of [HIPTN3N]Mo(NH3) to [HIPTN3N]Mo(N2) was studied and found to be increased in the presence of BPh3. [HIPTN3N]Mo(N2) conversion to [HIPTN3N]Mo(CO) was found to be dependent on CO pressure. Protonation studies of [HIPTN3N]Mo(N2) were also carried out. Studies of [HIPTN3N]MoNNH decomposition showed that decomposition is not base-catalyzed. [HIPTN3N]W(CO) was synthesized by exposure of [HIPTN3N]W(N2) to CO. It is a green, paramagnetic compound and its use as a standard (for determining relative concentrations of other compounds in the IR sample) in IR spectroscopic studies appears to be promising. [HIPTN3N]MoCNH2 was synthesized by addition of acid and reducing agent to [HIPTN3N]MoCN and is a yellow, diamagnetic compound. Two triamidophosphine ligands, triHIPTamine and tri-n-Buamine were synthesized. Metalation of Zr(NMe2)4 with these ligands leads to formation of pn3HIPTZrNMe2 and pn3-n- BuZrNMe2, both diamagnetic, pale yellow complexes.

Download or read book The Evolution of Molybdenum and Tungsten Olefin Metathesis Catalysts written by Annie Jinying Hannah King and published by . This book was released on 2010 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chapter 1: Reaction of Mo(NR)(CHR')(OTf)2(dme) (R = 2,6-i-Pr2C6H3 (Ar), 2,6-Me2C6H3 (Ar'), 2,6-Cl2C6H3 (ArCl), 1-adamantyl (Ad); R' = CMe2Ph, CMe3; dme = dimethoxyethane) with the lithium salt of ArCl-nacnac ([2,6-Cl2C6H3NC(Me)]2CH), led to complexes of the type Mo(NR)(CHCMe2R')(OTf)(ArCl-nacnac). Treatment of these compounds with Na{BArF 4} (ArF = 3,5-(CF3)2C6H3) afforded rare examples of cationic imido alkylidene complexes, {Mo(NR)(CHR')(OTf)(ArCl-nacnac)}{BArF 4}. Addition of {HNMe2Ph}{BArF 4} to Mo(NR)(CHR')(L)2 (L = NC4H4 (Pyr), 2,5-Me2NC4H2 (Me2Pyr)) in THF produced {Mo(NR)(CHR')(L)(THF)x}{BArF 4} (x = 2 for Me2Pyr or 3 for Pyr). Addition of alcohol or phenol to {Mo(NAr)(CHCMe2Ph)(Pyr)(THF)3}{BArF 4} produced {Mo(NAr)(CHCMe2Ph)(OR")(THF)x}{BArF 4} (R" = CMe(CF3)2 (x = 2 or 3), Ar (x = 1), Ad (x = 2)). Complexes Mo(NAr)(CHCMe2Ph)(MesPyr)2 (MesPyr = 2- mesitylpyrrolide), Mo(NAd)(CHCMe3)(MesPyr)2, and Mo(NAr)(CHCMe2Ph)(OTf)(BinaphPPh2) (BinaphPPh2 = (R)-2'-(diphenylphosphino)- [1,1'-binaphthalen]-2-oxide) were also generated. The solid-state structures of Mo(NAr)(CHCMe2Ph)(OTf)(ArCl-nacnac), {Mo(NAr)(CHCMe2Ph)(ArClnacnac)}{ BArF 4}, {Mo(NAr)(CHCMe2Ph)(Pyr)(THF)3}{BArF 4}, {Mo(NAr)(CHCMe2Ph)(OCMe(CF3)2)(THF)3}{BArF 4}, {Mo(NAr)(C2H4)(OCMe(CF3)2)(THF)3}{BArF 4}, {Mo(NAr)(CH2CMe2Ph)(OAr)2}{BArF 4}, Mo(NAr)(CHCMe2Ph)(MesPyr)2, and Mo(NAr)(CHCMe2Ph)(OTf)(BinaphPPh2) have been determined by X-ray diffraction. The initial reactivity with simple olefins employing many of these new alkylidenes was explored. Chapter 2: Two diastereomers of the MAP (monoaryloxidepyrrolide) species, W(NAr)(CH2)(Me2Pyr)(OBitetBr2) (OBitetBr2 = (R)-3,3'-dibromo-2'-(tertbutyldimethylsilyloxy)- 5,5',6,6',7,7',8,8'-octahydro-1,1'-binaphthyl-2-olate), were generated through addition of HOBitetBr2 to W(NAr)(CH2)(Me2Pyr)2. The unsubstituted tungstacyclobutane species, W(NAr)(C3H6)(Me2Pyr)(OBitetBr2), was isolated by exposing the methylidene species to ethylene. A variety of NMR experiments were carried out on the methylidene and metallacycle to elucidate the exchange process between these species. Neophylidene W(NR)(CHCMe2Ph)(Me2Pyr)(OTPP) (OTPP = 2,3,5,6-tetraphenylphenoxide), methylidene W(NR)(CH2)(Me2Pyr)(OTPP), and 6 tungstacyclobutane W(NR)(C3H6)(Me2Pyr)(OTPP) were prepared. Treatment of W(NAr)(CH2)(Me2Pyr)(OTPP) with PMe3 yielded yellow W(NAr)(CH2)(Me2Pyr)(OTPP)(PMe3). NMR studies on compounds W(NAr)(C3H6)(Pyr)(OHIPT) (OHIPT = 2,6-bis-(2,4,6-triisopropylphenyl)phenoxide) and Mo(NAr)(C3H6)(Pyr)(OHIPT) were carried out to examine the exchange process between the metallacyclobutane and the methylidene. Compounds W(NAr)(C3H6)(Me2Pyr)(OBitetBr2), W(NAr)(CH2)(Me2Pyr)(OTPP), W(NAr)(CH2)(Me2Pyr)(OTPP)(THF), W(NAr)(CH2)(Me2Pyr)(OTPP)(PMe3), W(NAr)(C3H6)(Me2Pyr)(OTPP), Mo(NAr)(CH2)(Pyr)(OHIPT), Mo(NAd)(CHCMe3)(Pyr)(OHIPT), and W(NAr)(C3H6)(Pyr)(OHIPT) were crystallographically characterized. Chapter 3: Molybdenum and tungsten catalysts of the type M(NR)(CHR')(Pyr)(OR'') were prepared for highly Z-selective homocoupling metathesis of terminal olefins. Substrates screened were: 1-hexene, 1-octene, allylbenzene, allyltrimethylsilane, methyl-9-decenoate, methyl- 10-undecenoate, allylboronic acid pinacol ester, allylbenzylether, allyltosylamide, Nallylaniline, allyloxy(tert-butyl)dimethylsilane, and allylcyclohexane. Homocoupled products were isolated in moderate yields employing 1 mol% catalyst loading and with90% Z-selectivity. Chapter 4: Exposing Mo(NAr)(C2H4)(MesPyr)2 to two equivalents of HOCH(CF3)2 afforded Mo(NAr)(C2H4)(OCH(CF3)2)2(Et2O). Mo(NAr)(C2H4)(OCH(CF3)2)(Et2O) was shown to isomerize and metathesize olefins such as propene, 1-hexene, and 1-octene at elevated temperatures. Evidence of isomerization and olefin metathesis was also observed with complexes Mo(NAd)(C2H4)(Pyr)(OHIPT) and Mo(NAr)(C2H4)(Me2Pyr)(OAr).

Download or read book Metals Ions in Biological System written by Astrid Sigel and published by CRC Press. This book was released on 2002-03-06 with total page 658 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volume 39: Molybdenum and Tungsten: Their Roles in Biological Processes is devoted soley to the vital research area on molybdenum and tungsten and their role in biology. It offers a comprehensive and timely account of this fascinating topic by 40 distinguished international authorities. Topics include: transport, homeostasis, regulation and binding of molybdate and tungstate to proteins, crystallographic characterization, coordination of complexes, and biosynthesis.

Download or read book Determination of the Distribution of Molybdenum and Tungsten Oxidation States in Reduced Molybdenum Tungsten titanium Dioxide Catalysts by X ray Photoelectron Spectroscopy with Factor Analysis and Curve Fitting written by Joseph Nicholas Fiedor and published by . This book was released on 1994 with total page 133 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Analytical Chemistry of Molybdenum and Tungsten written by W. T. Elwell and published by Elsevier. This book was released on 2013-10-22 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt: International Series of Monographs in Analytical Chemistry, Volume 47: Analytical Chemistry of Molybdenum and Tungsten describes the chemical and instrumental methods of analysis of molybdenum and tungsten. This book is composed of 15 chapters that particularly consider detailed methods for determining these metals in typical samples and their alloys by both classical and modern techniques. The opening chapters discuss the history, occurrence, physico-chemical properties, and applications of molybdenum and tungsten. The succeeding chapters deal with the metals’ sampling, decomposition, separation, and qualitative detection. Considerable chapters are devoted to various chemical and instrumental methods for their analysis, including gravimetry, titrimetry, colorimetry, polarography, amperometry, coulometry, emission and atomic absorption spectroscopy, X-ray spectrophotometry, mass spectrometry, and radiochemical methods. The concluding chapter examines the determination of impurities and alloying elements. This book will prove useful to analytical and inorganic chemists, as well as analytical and inorganic chemistry students.

Download or read book Tungsten written by Erik Lassner and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: Why does someone write a book about Tungsten? There are several reasons and precedents for this, the most important of which is that the last book on tungsten was written more than 20 years ago, in 1977, by St. W H. Yih and Ch T. Wang. During the intervening period there have been many new scientific and technological developments and innova tions, so it was not only our opinion but the view of many other members of the "tungsten family" that it was time to start writing a new book about tungsten. Preparations of the new book began in 1994. further impetus to the project was provided by the realization that in spite of this new knowledge having been presented at seminars or published in the technical press, a general acknowledgement of it by the majority of technicians and scientists is still far from being realized. It is our hope that this book will significantly contribute to a broader acceptance of recent scientific and technological innovations. An important prerequisite for such a project is the availability of a recently retired, experienced person willing to devote his time and talents to the tedious part of the exercise.

Download or read book Chromium Oxidations in Organic Chemistry written by G. Cainelli and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chromium oxidation, well known and widely explored in organic chemistry since the very beginning of this science, is a topic of current interest for the organic chemist as evidenced by the continuous development of new techni ques and procedures reported in the literature. Chromium oxidation is a simple process which can be easily performed in the laboratory and scaled up in industry as well. Although almost every oxidizable organic functional group may undergo chromium oxidation, the most important fields of appli cation are the oxidation of alcohols, allylic and benzylic oxidation, oxidative degradation and oxidation of some organometallic compounds. A high degree of selectivity is often possible by choosing the most suitable reagent among those several ones now available. This book takes account of the various functional groups that undergo oxidation and the entire literature up to 1982. It has been written in the hope to help the synthetic organic chemist in his experimental work. For this purpose a number of tables comprising yields and references have been included; detailed descriptions of typical procedures are meant to show the experimental conditions and the scope of the reactions. We wish to thank Dr. Mario Orena for his valuable scientific and technical assistence and Prof. Bruno Camerino, who read the entire manuscript and corrected many of the errors. Bologna, February 1984 Gianfranco Cainelli Giuliana Cardillo Table of Contents I. Introduction . . . . . . . . . . .