Download or read book Platinum Carbene Complexes with One Heteroatom Bonded to Carbene Carbon Synthesis and Mechanisms written by and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book N Heterocyclic Carbenes in Organocatalysis written by Akkattu T. Biju and published by John Wiley & Sons. This book was released on 2019-03-04 with total page 556 pages. Available in PDF, EPUB and Kindle. Book excerpt: Summarizing the emerging field of N-heterocyclic carbenes used in organocatalysis, this is an excellent overview of the synthesis and applications of NHCs focusing on carbon-carbon and carbon-heteroatom bond formation. Alongside comprehensive coverage of the synthesis, characteristics and applications, this handbook and ready reference also includes chapters on NHCs for polymerization reactions and natural product synthesis.

Download or read book Synthesis and Reactivity of Ruthenium and Platinum Amido and Carbene Complexes Application Toward Carbon Nitrogen Bond Forming Reactions written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Ru carbene complexes have been investigated for potential application toward carbon-nitrogen bond forming and breaking reactions. The reactivity of Grubbs-type olefin metathesis catalysts (Cl)2(L)(L')Ru=CHPh (L = L' = PCy3 or PPh3; L = PCy3 and L' = H2MesNHC) has been studied with cyclic and acyclic imines. The Ru benzylidene complex (Cl)2(PCy3)2Ru=CHPh undergoes a ligand exchange reaction with 1-pyrroline at room temperature, and oligomerizes 1-pyrroline at 90 oC. The low molecular weight poly(1-pyrroline) has been isolated and characterized. The Ru benzylidene complex has no reactivity toward acyclic imine C=N bonds, but reacts with enamine C=C bonds that form through tautomerization of imines. The Ru amido complexes, (PCP)Ru(CO)(NHPh) and (PCP)Ru(CO)(NHPh)(PMe3) (PCP = 2,6-(CH2P-t-Bu2)C6H3), have been synthesized and characterized. Reaction of (PCP)Ru(CO)(NHPh)(PMe3) with acetonitrile produces the amidinate complex (PCP)Ru(CO)(NHC(Me)NPh). Kinetic studies have demonstrated the formation of the amidinate complex occurs through dissociation of the PMe3 ligand, coordination of MeCN, and intramolecular nucleophilic attack of the amido ligand toward MeCN. The intramolecular nucleophilic attack reaction has been extensively studied with aromatic nitriles, carbodiimides, isocyanates, carboxamides and aldehydes. Reaction of (PCP)Ru(CO)(NHC(Me)NPh) with pentafluorobenzonitrile results in formation of a new amidinate complex (PCP)Ru(CO)(NHC(C6F5)NPh). The complex (PCP)Ru(CO)(NHC(C6F5)NPh) can initiate a C-F bond cleavage reaction of C6F5CN with ortho regioselectivity in the presence of ROH (R = H or Me). Reaction of five-coordinate complex (PCP)Ru(CO)(OTf) (OTf = OSO2CF3) with NaBAr'4 (Ar' = 3,5-(CF3)2C6H3) under different conditions results in formation of [(PCP)Ru(CO)(ClCH2Cl)][BAr'4], [(PCP)Ru(CO)(N2)][BAr'4] or [(PCP)Ru(CO)(FC6H5)][BAr'4]. Calculations have confirmed that the possible four-coordinate Ru complex with double agostic interactions has a higher ground state.

Download or read book Functionalised N Heterocyclic Carbene Complexes written by Olaf Kühl and published by Wiley. This book was released on 2010-02-02 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt: N-heterocyclic carbenes (NHCs) have found increasing use as reagents for a range of organic transformations and in asymmetric organocatalysis. The performance of these molecules can be improved and tuned by functionalisation. Functionalised carbenes can anchor free carbenes to the metal site, introduce hemilability, provide a means to immobilise transition metal carbene catalysts, introduce chirality, provide a chelate ligand or bridge two metal centres. NHC can be attached to carbohydrates and campher, derived from amino acids and purines, they can be used as organocatalysts mimicking vitamin B1 or as weak “solvent” donors in lanthanide chemistry. Functionalised N-Heterocyclic Carbene Complexes describes major trends in functionalised NHC ligands, aiming to assist readers in their attempts to develop and apply their own functionalised carbenes. After an introduction to the chemistry and behaviour of NHC, the book gives a detailed description of functionalised carbenes and their complexes according to a range of functional groups, each with a discussion of the synthetic route, structure, stability and performance. Functionalised N-Heterocyclic Carbene Complexes is an essential guide to fine-tuning this important class of compounds for practitioners, researchers and advanced students working in synthetic organometallic and organic chemistry and catalysis.

Download or read book Carbene written by Satyen Saha and published by BoD – Books on Demand. This book was released on 2022-03-30 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbenes are important molecules in chemistry because of their photochemistry and high reactivity. They have many potential applications in medicinal and materials chemistry. This book provides a comprehensive introduction to carbenes and discusses their characteristics, structure, and synthesis procedures. It gives special emphasis to N-heterocyclic carbenes (NHCs) and their metal complexes.

Download or read book N heterocyclic Carbenes written by Carol A. Quezada and published by . This book was released on 2005 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This dissertation discusses the synthesis of different N-heterocyclic carbene precursors, the synthesis of an N-heterocyclic carbene from the precursor, the synthesis of N-heterocyclic carbene complexes of platinum and rhodium, as well as the transfer of N-heterocyclic carbenes from silver to rhodium, and to a smaller extent about the synthesis of previous heterocyclynes. In Chapter 1, the properties and preparation of N-heterocyclic carbenes and carbene salts are discussed. The bonding of N-heterocyclic carbenes as opposed to the bonding of Fischer and Schrock carbenes to metal centers is reviewed. The synthesis of platinum complexes of N-heterocyclic carbenes is illustrated. The synthesis of some of the many heterocyclynes with platinum at the corners is also discussed. The synthesis of the first silver N-heterocyclic carbene complex to use silver(I) oxide is discussed as well as the transfer of the carbene from silver to other metals with an emphasis on the transfer to rhodium. The synthesis of the various rhodium complexes of N-heterocyclic carbenes is also discussed. In Chapter 2 the synthesis of the first bis(N-heterocyclic carbene) complex of platinum is discussed as well as the synthesis of the building blocks to form the heterocyclyne. The high yield synthesis of the heterocyclyne composed of N-heterocyclic carbene platinum complexes at the corners and butadiyde fragments on the periphery is illustrated. In Chapter 3 the syntheses of the N-heterocyclic carbene complexes of silver are reported as well as the first transfer of a carbene from silver to rhodium trichloride hydrate, a necessary step in the direction of using N-heterocyclic carbene complexes of rhodium as radiopharmceuticals. An alternate approach to the synthesis of a rhodium N-heterocyclic carbene complex is also discussed."--Page iii-iv.

Download or read book N Heterocyclic Carbenes written by Silvia Diez-Gonzalez and published by Royal Society of Chemistry. This book was released on 2016-11-08 with total page 636 pages. Available in PDF, EPUB and Kindle. Book excerpt: In less than 20 years N-heterocyclic carbenes (NHCs) have become well-established ancillary ligands for the preparation of transition metal-based catalysts. This is mainly due to the fact that NHCs tend to bind strongly to metal centres, avoiding the need of excess ligand in catalytic reactions. Also, NHC‒metal complexes are often insensitive to air and moisture, and have proven remarkably resistant to oxidation. This book showcases the wide variety of applications of NHCs in different chemistry fields beyond being simple phosphine mimics. This second edition has been updated throughout, and now includes a new chapter on NHC‒main group element complexes. It covers the synthesis of NHC ligands and their corresponding metal complexes, as well as their bonding and stereoelectronic properties and applications in catalysis. This is complemented by related topics such as organocatalysis and biologically active complexes. Written for organic and inorganic chemists, this book is ideal for postgraduates, researchers and industrialists.

Download or read book Organic Synthesis written by Belakatte Parameshwarappa Nandeshwarappa and published by BoD – Books on Demand. This book was released on 2020-05-27 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book ‘Organic Synthesis - A Nascent Relook’ is a compendium of the recent progress in all aspects of organic chemistry including bioorganic chemistry, organo-metallic chemistry, asymmetric synthesis, heterocyclic chemistry, natural product chemistry, catalytic, green chemistry and medicinal chemistry, polymer chemistry, as well as analytical methods in organic chemistry. The book presents the latest developments in these fields. The chapters are written by chosen experts who are internationally known for their eminent research contributions. Organic synthesis is the complete chemical synthesis of a target molecule. In this book, special emphasis is given to the synthesis of various bioactive heterocycles. Careful selection of various topics in this book will serve the rightful purpose for the chemistry community and the industrial houses at all levels.

Download or read book Carbene Chemistry written by Guy Bertrand and published by CRC Press. This book was released on 2002-05-14 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: Highlights recent discoveries in the development of rapid kinetic techniques that allow for direct visualization and state-of-the-art computational methods.

Download or read book Comprehensive Organic Functional Group Transformations Synthesis carbon with one heteroatom attached by a single bond written by Alan R. Katritzky and published by Elsevier. This book was released on 1995-12-29 with total page 1474 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fischer and N heterocyclic Carbene Complexes of Chromium 0 written by Roan Fraser and published by . This book was released on 2012 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt: The central focus of this study was the synthesis, structural investigation and characterisation of multiple chromium carbene complexes. Fifteen novel chromium(0) complexes were synthesised. The synthesis of the primary monocarbene starting material [Cr(CO)5{C(OEt)(heteroaryl)}], heteroaryl = thiophene, furan, 2,2’-bithiophene, was carried out utilising typical Fischer methodology. A wide variation of spacer ligands were reacted to obtain different carbene substituents. The ligand substitution reaction between carbonyl ligands and the bidentate ligands followed the techniques proposed in literature and produced distinctive chelated monocarbene complexes with the resulting structure mer- [Cr(CO)3(dppe){carbene)}]. An extensive collection of more sophisticated monocarbene complexes was synthesised via modification pathways (aminolysis). Conversion of original ethoxy-bearing monocarbenes through aminolysis provided the corresponding amine analogues, possessing both novel structure and unique chemical reactivity. The aminolysis reactions involved different sized amino reagents; both ammonia and cyclohexyl amine (bulky, cyclic chair amines) were employed to produce derivatives of the monocarbene starting complexes. Lastly, the synthesis of unique N-heterocyclic carbene (NHC) complexes was envisaged. Synthesis of both the pentacarbonyl-bearing and phosphine-bearing NHC complexes was attempted utilising an adapted version of a methodology proposed in literature. The synthesis of chelate NHC complexes, however, proved difficult and the resulting products were not obtained. All Fischer and N-heterocyclic carbene complexes were characterised using infrared spectroscopy, nuclear magnetic resonance spectroscopy and mass spectrometry. In cases where single crystals were obtained, X-ray crystallography was used to confirm molecular structures. X-ray crystallographic studies indicated that carbonyl substitution reactions performed on monocarbene starting material, will favour the formation of the meridonial isomer in molecules where the carbene substituents are less bulky. Due to steric considerations, the substitution of labile carbonyl ligands in the trans position to the carbene moiety will be favoured. Density functional theory (DFT) calculations were performed on the complexes synthesised in this study. The results obtained indicated the favoured isomeric form to be facial in some cases whereas crystallographic data signified the meridonial isomer as the more stable product, irrespective of the bulkiness of the carbene substituents. Bond lengths, geometry and bond angles were all comparable to those of the single-crystal X-ray data. Single-point energy calculations show clearly that modelling methods provide good estimations of energetically favourable geometries, and accurate DFT calculations also predict the HOMO and LUMO orientations around the metal or ligand spheres. The majority of the structures provided by the computed model, illustrated that the 3d atomic orbitals of the metal contributed significantly to the HOMO, whereas the LUMO was mostly orientated around the carbene carbon atom. Metathesis and polymerisation catalytic reactions were attempted on [Cr(CO)3(dppe){C(OEt)(thiophene)}], 2, whereas only metathesis studies were employed for [Cr(CO)3(dppe){C(NHCy)(thiophene)}], 6. Both complexes presented as inert to either reaction and no catalytic capability was witnessed. Gas chromatography was used to indicate the level of progression of the reaction and the chromatogram verified that neither pre-catalyst found application in metathesis or, in the case of 2, in polymerisation.

Download or read book Multimetal Complexes of Fischer Carbenes written by Daniela Ina Bezuidenhout and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Fischer carbene complexes of the Group VI transition metals (Cr, Mo and W) containing at least two or three different transition metal substituents, all in electronic contact with the carbene carbon atom, were synthesized and studied both in solution and in the solid state. For the complexes of the type [M(CO)5{C(OR)R }], the substituents chosen included (hetero)aromatic (benzene or thiophene) rings ; -bonded to a chromium tricarbonyl fragment or ferrocene as the R -substituent, while the OR-substituent was systematically varied between an ethoxy or a titanoxy group, to yield the complexes 1 (M = Cr, R = Et, R = Fc), 2 (M = W, R = Et, R = Fc), 5 (M = Cr, R = TiCp2Cl, R = Fc), 6 (M = W, R = TiCp2Cl, R = Fc), 7 (M = Mo, R = TiCp2Cl, R = Fc), 12 (M = Cr, R = TiCp2Cl, R = 2-thienyl) and 13 (M = Cr, R = TiCp2Cl, R = [Cr(CO) 3 (? 6-phenyl)]). Direct lithiation of the ferrocene with n-BuLi/TMEDA at elevated temperatures, followed by the Fischer method of carbene preparation, also resulted, in most cases, in the formation of the novel biscarbene complexes with bridging ferrocen- 1,1 -diyl carbene ligands [-Fe{C5H4C(OEt)M(CO) sub>5}2] (3: M = Cr, 4: M = W) or the unusual bimetallacyclic bridged biscarbene complexes [{ -TiCp2O2-O, O }{ - Fe(C5H4)2-C, C }{CM(CO) 5}2] (8: M = Cr, 9: M = W, 10: M = Mo). It was attempted to prepare the mixed heteronuclear biscarbene complex 11 [W(CO) 5C{ -TiCp2O2- O, O }{ -Fe(C5H4)2-C, C }CCr(CO) 5], however the complex could not be fully characterized. The investigation was expanded to include Group VII transition metals Mn and Re, and using the same methodology, the manganese complexes isolated included [MnCp(CO2{C(OR)Fc}] (22: R = Et, 24: R = TiCp2Cl), 23 [- Fe{C5H4C(OEt)MnCp(CO) 2}2] and 25 [{ -TiCp2O2-O, O }{ - Fe(C5H4)2- C, C }[CMnCp(CO) 2}2]. The different reactivity of the binary dirhenium decacarbonyl precursor complex, compared to that of the Group VI complexes, resulted in the formation of a range of complexes. The target compounds [Re2 (CO) 9{C(OR)Fc}] (26: R = Et, 31: R = TiCp2Cl), 27 [-Fe{C5H4C(OEt)Re2 (CO) 9}2] and 33 [{ - TiCp2O2-O, O }{ -Fe(C5H4)2-C, C }[CRe2 (CO) 9}2] were isolated displaying a variety of different geometric isomers. In addition, acyl (30) and aldehyde (32) decomposition products, as well as hydrido (29), and hydrido acyl hydroxycarbene (34) complexes and the unique dichloro-bridged biscarbene complex (28) were also characterized. Most of these complexes displayed Re-Re bond breaking, and two probable mechanisms, either radical or ionic, were proposed involving either hydrogen transfer or protonation followed by hydrolysis. Finally, the structural features and their relevance to bonding in the carbene cluster compounds of the Group VI transition metals were investigated as they represent indicators of possible reactivity sites in multimetal carbene assemblies. The possibility of using DFT calculations to quantify the effect of metal-containing substituents on the carbene ligands was tested and correlated with experimental parameters by employing methods such as vibrational spectroscopy, molecular orbital analysis, and cyclic voltammetry. The best results were obtained from the cyclic voltammetric studies, where the localized metal centre's oxidation potential correlated to both the calculated HOMO energy, and the effect of both the heteroatom substituent and the (hetero)arene substituent, as well as different combinations of the above.

Download or read book Modern Catalytic Methods for Organic Synthesis with Diazo Compounds written by Michael P. Doyle and published by Wiley-Interscience. This book was released on 1998-01-19 with total page 680 pages. Available in PDF, EPUB and Kindle. Book excerpt: This much-needed resource brings together a wealth of procedures for the synthesis and practical use of diazocarbonyl compounds. It features methods for the preparation of important catalysts and for applications of diazocarbonyl compounds within each of the main transformation categories-including in-depth coverage of cyclopropanation, C-H and X-H insertion, Wolff rearrangement, ylide formation, aromatic cycloaddition and substitution, and many other useful reactions. Written by leading experts in the field, this book contains cutting-edge material on highly enantioselective transformations, and presents new ways of thinking about diazocarbonyl compounds and their applications, from donor-acceptor cyclopropanes in organic synthesis to macrocyclic cyclopropanation. Complete with illustrative examples of procedures in each chapter, clear diagrams, and a detailed bibliography, this practical reference gives readers the tools they need to put diazocarbonyl compounds to work for their own projects-an invaluable source of guidance for synthetic organic chemists, chemical scientists, and advanced students.

Download or read book Chiral Ferrocenes in Asymmetric Catalysis written by Li-Xin Dai and published by John Wiley & Sons. This book was released on 2010-02-01 with total page 433 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book meets the long-felt need for a reference on ferrocenes with the focus on catalysis. It provides a thorough overview of the synthesis and characterization of different types of chiral ferrocene ligands, their application to various catalytic asymmetric reactions, and versatile chiral materials as well as drug intermediates synthesized from them. Written by the "who's who" of ferrocene catalysis, this is a guide to the design of new ferrocene ligands and synthesis of chiral synthetic intermediates, and will thus be useful for organic, catalytic and synthetic chemists working in academia, industrial research or process development.

Download or read book The Organometallic Chemistry of the Transition Metals written by Robert H. Crabtree and published by John Wiley & Sons. This book was released on 2005-06-14 with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fully updated and expanded to reflect recent advances, this Fourth Edition of the classic text provides students and professional chemists with an excellent introduction to the principles and general properties of organometallic compounds, as well as including practical information on reaction mechanisms and detailed descriptions of contemporary applications.

Download or read book The Mizoroki Heck Reaction written by Martin Oestreich and published by John Wiley & Sons. This book was released on 2009-02-11 with total page 608 pages. Available in PDF, EPUB and Kindle. Book excerpt: Exploring the importance of Richard F. Heck’s carbon coupling reaction, this book highlights the subject of the 2010 Nobel Prize in Chemistry for palladium-catalyzed cross couplings in organic synthesis, and includes a foreword from Nobel Prize winner Richard F. Heck. The Mizoroki-Heck reaction is a palladium-catalyzed carbon–carbon bond forming process which is widely used in organic and organometallic synthesis. It has seen increasing use in the past decade as chemists look for strategies enabling the controlled construction of complex carbon skeletons. The Mizoroki-Heck Reaction is the first dedicated volume on this important reaction, including topics on: mechanisms of the Mizoroki-Heck reaction intermolecular Mizoroki-Heck reactions focus on regioselectivity and product outcome in organic synthesis waste-minimized Mizoroki-Heck reactions intramolecular Mizoroki-Heck reactions formation of heterocycles chelation-controlled Mizoroki-Heck reactions the Mizoroki-Heck reaction in domino processes oxidative heck-type reactions (Fujiwara-Moritani reactions) Mizoroki-Heck reactions with metals other than palladium ligand design for intermolecular asymmetric Mizoroki-Heck reactions intramolecular enantioselective Mizoroki-Heck reactions desymmetrizing Mizoroki-Heck reactions applications in combinatorial and solid phase syntheses, and the development of modern solvent systems and reaction techniques the asymmetric intramolecular Mizoroki-Heck reaction in natural product total synthesis Several chapters are devoted to asymmetric Heck reactions with particular focus on the construction of otherwise difficult-to-obtain sterically congested tertiary and quaternary carbons. Industrial and academic applications are highlighted in the final section. The Mizoroki-Heck Reaction will find a place on the bookshelves of any organic or organometallic chemist. “I am convinced that this book will rapidly become the most important reference text for research chemists in academia and industry who seek orientation in the rapidly growing and – for the layman – confusing field described as the “’Mizoroki–Heck reaction’.” (Synthesis, March 2010)

Download or read book N Heterocyclic Carbenes in Transition Metal Catalysis written by Frank Glorius and published by Springer. This book was released on 2007-02-05 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book leading experts have surveyed major areas of application of NHC metal complexes in catalysis. The authors have placed a special focus on nickel- and palladium-catalyzed reactions, on applications in metathesis reactions, on oxidation reactions and on the use of chiral NHC-based catalysts. This compilation is rounded out by an introductory chapter and a chapter dealing with synthetic routes to NHC metal complexes.