Download or read book Synthesis of Group IV Imido Complexes Supported by diketiminate Ligands written by Jie Fang and published by . This book was released on 2001 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis of Group IV Metal Complexes Employing a Newly Developed Orthometallated Imine Ligand System written by Tamam Issa Baiz and published by . This book was released on 2007 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Imido Complexes of the Heavier Group 5 Metals Supported by an N N diaryl beta diketiminato Ligand written by Neil Carleton Tomson and published by . This book was released on 2009 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis Structure and Reactivity of Mickel Monoalkyl Imido and Amido Complexes Supported by Beta diketiminate Ligands written by Elzbieta Kogut and published by . This book was released on 2004 with total page 418 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis and Reactivity of Reduced Niobium Imido Complexes written by Thomas Lucien Gianetti and published by . This book was released on 2014 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation is presented the synthesis and reactivity of Nb(III) imido complexes supported by the BDI ligand (BDI = &beta-diketimate). Chapter I. The discovery of a Nb(III)-mediated catalytic hydrogenation of internal alkynes to Z-alkenes is reported and found to proceed through an unprecedented mechanism. The mechanistic proposal involves initial reduction of the alkyne by the Nb(III) complex (BDI)Nb(NtBu)(CO)2 to provide a Nb(V) metallacyclopropene, itself capable of &sigma-bond metathesis reactivity with H2. The resulting alkenyl hydride species then undergoes reductive elimination to provide the Z-alkene product and regenerate a metal complex in the Nb(III) oxidation state. Support for the proposed mechanism is derived from i) the dependence of product selectivity on the relative concentrations of CO and H2, ii) the isolation of complexes closely related to those proposed to lie on the catalytic cycle, iii) H/D crossover experiments, and iv) DFT studies on multiple possible reaction pathways. Chapter II. Monometallic niobium arene complexes [Nb(BDI)(NtBu)(&mu-RC6H5)] (R = H and Me) were synthesized and were found to slowly converted into the diniobium inverted arene sandwich complexes [[(BDI)Nb(NtBu)]2(&mu-RC6H5)] (R = H and Me) in solution. The kinetics of this reaction were followed by 1H NMR spectroscopy, and is in agreement with a dissociative mechanism. These compounds showed a lack of reactivity towards small molecules - even at elevated temperatures - which is unusual in the chemistry of inverted sandwich complexes. However, protonation of the BDI ligands occurred readily on treatment with [H(OEt2)][B(C6F5)4], resulting in the mono-protonated cationic inverted sandwich complex [[(BDI#)Nb(NtBu)][(BDI)Nb(NtBu)](&mu-C6H5)][B(C6F5)4] and the dicationic complex [[(BDI#)Nb(NtBu)]2(&mu-RC6H5)][B(C6F5)4]2 (BDI# = (ArNC(Me))2CH2). NMR and UV-vis spectroscopies were used to characterize this unique series of diamagnetic molecules as a means of determining how best to describe the Nb-arene interactions. The X-ray crystal structures, UV-visible spectra, arene 1H NMR chemical shifts and large JCH coupling constants provide evidence for donation of electron density from the Nb d-orbitals into the antibonding [pi] system of the arene ligands. However, the lack of sp3 hybridization of the arene carbon indicate that the Nb-arene donation is not accompanied by an increase in formal oxidation state, and suggest that 4d2 electronic configurations are appropriate to describe the Nb atoms in all four complexes. Chapter III. Inverted sandwich complexes have seen interesting recent developments both in the nature of their bonding and in their use as chemical reactants. Although discussions concerning the electronic delocalization lend credit to their use as potential electronic and spintronic devices, mixed valent inverted sandwich complexes are rarely reported. We show in this work that the selective single electron oxidation of a neutral benzene inverted sandwich complex of niobium leads to an isolable cationic mixed valent benzene inverted sandwich complex. The latter complex shows unique structural features elucidated through studies with an arsenal of physical methods, including cyclic voltammetry, 1H NMR, UV-Vis, magnetism, EPR spectroscopies, in addition to DFT calculations. These analyses indicate that although delocalization is allowed over the benzene ring from both niobium atoms, the single electron is unequally shared between the two metal centres. Under certain conditions, this complex reforms the neutral benzene complex along with a highly reactive Nb(IV) species, which is of great interest for potential chemical reactivity. Chapter IV. All three C-F bonds in CF3-substituted arenes are activated by a niobium imido complex, driven by the formation of strong Nb-F bonds. The mechanism of this transformation was studied by NMR spectroscopy which revealed the involvement of Nb(III). Attempts to extend this chemistry to non-aromatic CF3 groups led to intramolecular reactivity.The mechanism of activation of C-F bonds in fluoroarenes using a well-defined niobium (III) imido complex has been investigated. Chapter V. The Nb(III) arene species [BDI]Nb(NtBu)(C6H6), reacts stoichiometrically with fluoroarenes to yield niobium (V) aryl fluorides. Spectroscopic analysis supported by DFT calculations revealed the critical involvement of a Nb(III) fluoroarene-bound species. In contrast to previous reports of related reactivity, we found that perfluorinated arenes (i.e. those normally assumed to bear more `activated' C-F bonds) are, in the present system, much less reactive towards C-F bond cleavage than mono- or difluoro-substituted arenes. In addition to demonstrating stoichiometric hydrodefluorination reactions, we also describe an efficient and mild hydrodefluorination of mono- and di-fluoroarenes that is catalytic in niobium.

Download or read book Synthesis of Group 4 Metal diketimine Complexes written by William James Scanlon and published by . This book was released on 1998 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Inorganic Syntheses Volume 35 written by and published by John Wiley & Sons. This book was released on 2010-08-13 with total page 221 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Inorganic Syntheses series provides all users of inorganic substances with detailed and foolproof procedures for the preparation of important and timely compounds. Includes complete, up-to-date procedures involving important inorganic substances Contains subject, contributor, and formula indexes

Download or read book Synthesis of Group V Metal Imido Complexes Employing Newly Developed Orthometallated Aldimine and Ketimine Ligands written by Cheryl L. Seambos and published by . This book was released on 2007 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis Structure and Reactivity of Group 13 Diketiminate Complexes written by Baixin Qian and published by . This book was released on 1999 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Photochemistry and Photophysics of Coordination Compounds written by Rakshit Ameta and published by Elsevier. This book was released on 2023-06-24 with total page 426 pages. Available in PDF, EPUB and Kindle. Book excerpt: Photochemistry and Photophysics of Coordination Compounds: Fundamentals and Applications provides a systematic overview of the photochemical and photophysical properties of coordination compounds with different metal cores. Beginning with a clear introduction to the fundamentals of both photochemistry and coordination chemistry, the book goes on to outline the photochemical and photophysical properties of a large range of coordination compounds, clustering metal cores together in chapters according to their period table group, ranging across Transition metals, Lanthanides and Actinides. In addition to outlining their properties, each chapter discusses the synthesis, current applications and future potential of coordination compounds in each group. Drawing on the experience of a global team of experts, this book is an authoritative guide for all those interested in understanding and harnessing the photochemical properties and potential applications of coordination complexes for their own work. Introduces the fundamentals of both photochemistry and coordination compounds Supports learning through carefully structured content, with chapters uniquely arranged by period table group Bridges the knowledge gap between theory and practice by presenting application examples in each chapter

Download or read book Development of Bulky Dipyrromethene Complexes of Aluminum Zinc and Rhodium written by Christopher G. Gianopoulos and published by . This book was released on 2014 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt: The chemistry of dipyrromethene ligands is dominated by boron difluoride luminophores (BODIPY), which are commercially important laser dye materials and have also found application to imaging/staining biological samples. Despite the importance of BODIPY complexes, dipyrromethene complexes of the heavier group 13 elements are scarce. Our interest in bulky dipyrromethene ligands is based on analogy to popular ß-diketiminate ligands that have found use in stabilizing unusual metal complexes on the basis of steric protection. The preparation and characterization of aluminum, zinc and rhodium complexes of bulky dipyrromethene ligands is the subject of the following discourse. The preparation and characterization of aluminum alkyl, aryl and hydride complexes of 1,9-dimesityl-5-phenyldipyrromethene is reported in chapter two. The synthesis and characterization of a bimetallic aluminoxane with terminal hydride coligands is also reported. The preparation and characterization of dimethylaluminum complexes of 1,9-dimesityl-5-pentafluorophenyldipyrromethene and 1,9-dimesityl-5-(2'-pyridyl)dipyrromethene are also reported. These compounds have been characterized by NMR spectroscopy and X-ray crystallography. The structural data clearly demonstrate similarities and differences of the steric environment of dipyrromethene and ß-diketiminate ligands. The alkyl and aryl aluminum complexes are surprisingly robust and tolerate exposure to air, moisture and even silica gel chromatography. We have proposed that the stability of these compounds is due to kinetic stabilization afforded by the steric environment of the bulky dipyrromethene ligand. The preparation of aluminum complexes of 1,9-dimesityl-5-phenyldipyrromethene is extended in chapter 3. In this chapter, the preparation of aluminum complexes with halide, alkoxide and amido coligands is reported. These complexes were characterized by NMR spectroscopy and X-ray crystallography. The alkoxide and amido complexes were also evaluated for their ability to initiate the polymerization of e-caprolactone and preliminary results are discussed. Unfortunately, these aluminum complexes are poor catalysts for caprolactone polymerization, which only proceeds at elevated temperature. Furthermore, the aluminum catalysts are sensitive to impurities in the lactone monomer and catalysis was often found to halt after long reaction times. As mentioned previously, we became interested in the chemistry of aluminum complexes of dipyrromethene ligands based on analogy to ß-diketiminate ligands. ß-Diketiminate ligands have found use in stabilizing rare metal complexes, such as terminal imido complexes of aluminum. A major aim of our work with dipyrromethenes is to identify a system capable of stabilizing aluminum complexes with terminal divalent coligands such as imido or alkylidene ligands. In chapter 4, theoretical calculations performed at the DFT level are presented. The electronic structure of dipyrromethene aluminum complexes with terminal imido and alkylidene coligands was calculated as well as the thermochemical parameters of reactions to prepare such complexes. Synthetically viable substitutions were made in order to determine the effect of electronic perturbations (to the dipyrromethene or alkylidene coligand) on the stability of terminal alkylidene complexes of aluminum. The results of this chapter show that a terminal alkylidene of aluminum must be formed from an Al(I) precursor, rather than Al(III), and also that modification of the electronics of these systems has little effect on the stability of the resulting complexes. These results indicate that isolation of a stable, terminal alkylidene complex of aluminum will likely require kinetic stabilization of the reactive alkylidene moiety by use of steric bulk rather than stabilization through electronic modification to the system. Chapter 5 concerns the preparation and characterization of zinc halide, alkyl and alkoxide complexes of 1,9-dimesityl-5-phenyldipyrromethene. These compounds have been characterized by NMR spectroscopy and X-ray crystallography. The preparation of monomeric zinc alkoxides has been challenging and results to this aim are discussed at length. As an extension of the work reported in chapter 3, we have also explored the polymerization of e-caprolactone initiated by zinc alkoxide complexes and preliminary results will be discussed. In chapter 6 the preparation and characterization of rhodium(I) 1,5-cyclooctadiene (COD), carbon monoxide (CO) and arene complexes of 1,9-dimesityl-5-pentafluorophenyldipyrromethene are reported. These complexes were characterized by NMR spectroscopy and X-ray crystallography. Results from this chapter demonstrate the flexibility of the dipyrromethene ligand to accommodate square-planar coordination to rhodium(I). The preparation of low-coordinate rhodium complexes is also discussed. Chapter 7 reports the synthesis of Cr(TPP)Cl(THF), a component of the Coates system for carbonylation of epoxides, by a previously unreported method. Traditionally, Cr(TPP)Cl(THF) is prepared from divalent or zero-valent chromium precursors that are expensive, air-sensitive materials. Our method involves the use of inexpensive, air-stable trivalent chromium. Appendix 1 reports the synthesis and characterization of three compounds which were prepared as parts of side projects. The experimental details and crystal structures are reported, discussion is however kept to a minimum. The compounds presented in the appendix include nickel bromide and chromium chloride complexes of 1,9-dimesityl-5-phenyldipyrromethene and also a pseudo-octahedral homoleptic aluminum complex ligated by 2-(2'-pyridyl)pyrrole.

Download or read book Nickel Catalysis in Organic Synthesis written by Sensuke Ogoshi and published by John Wiley & Sons. This book was released on 2020-03-09 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive reference to nickel chemistry for every scientist working with organometallic catalysts Written by one of the world?s leading reseachers in the field, Nickel Catalysis in Organic Synthesis presents a comprehensive review of the high potential of modern nickel catalysis and its application in synthesis. Structured in a clear and assessible manner, the book offers a collection of various reaction types, such as cross-coupling reactions, reactions for the activation of unreactive bonds, carbon dioxide fixation, and many more. Nickel has been recognized as one of the most interesting transition metals for homogeneous catalysis. This book offers an overview to the recently developed new ligands, new reaction conditions, and new apparatus to control the reactivity of nickel catalysts, allowing scientists to apply nickel catalysts to a variety of bond-forming reactions. A must-read for anyone working with organometallic compounds and their application in organic synthesis, this important guide: -Reviews the numerous applications of nickel catalysis in synthesis -Explores the use of nickel as a relatively cheap and earth-abundant metal -Examines the versatility of nickel catalysis in reactions like cross-coupling reactions and CH activations -Offers a resource for academics and industry professionals Written for catalytic chemists, organic chemists, inorganic chemists, structural chemists, and chemists in industry, Nickel Catalysis in Organic Synthesis provides a much-needed overview of the most recent developments in modern nickel catalysis and its application in synthesis.

Download or read book Activation of Small Molecules written by William B. Tolman and published by John Wiley & Sons. This book was released on 2006-12-13 with total page 382 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first to combine both the bioinorganic and the organometallic view, this handbook provides all the necessary knowledge in one convenient volume. Alongside a look at CO2 and N2 reduction, the authors discuss O2, NO and N2O binding and reduction, activation of H2 and the oxidation catalysis of O2. Edited by the highly renowned William Tolman, who has won several awards for his research in the field.

Download or read book Dissertation Abstracts International written by and published by . This book was released on 2008 with total page 850 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Steric and Electronic Effects of the beta diketiminate Ligand on Low coordinate Iron Complexes written by Sarina M.. Bellows and published by . This book was released on 2014 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This work focuses on the steric and electronic effects of the [beta]-diketiminate ligand when coordinated to iron. Smaller [beta]-diketiminates were used in comparison to their bulkier analogues. The effects of the [beta]-diketiminate on iron complexes and their reactivities were investigated by density function theory studies, kinetic studies, and by comparing spectroscopic data to analogous compounds. Chapter 1 introduces the various [beta]-diketimines and their synthetic preparations. This supporting ligand can provide a range of steric hindrance which has resulted in differences in reactivity of the iron complexes. The few studies of [beta]-diketimines with electron withdrawing groups are discussed in detail to understand the current knowledge of electronic effects of the [beta]-diketiminate ligand. Chapter 2 describes the DFT study of [beta]-hydride elimination via high-spin iron(II)- and cobalt(II)-alkyl complexes. For these high-spin complexes to acquire the empty d orbital necessary for [beta]-hydride elimination a spin flip must occur to access a lower spin state. In the iron(II)-alkyl and cobalt(II)-alkyl complexes, a spin crossover mechanism was calculated to occur in order to obtain the lowest energy transition state through a lower spin state than the starting alkyl complex. This study has also given insight into an iron(II) complex that is resistant to [beta]-hydride elimination due to the steric hindrance of the ligand. Chapter 3 describes the synthesis of a ([beta]-diketiminate)iron(I) dimer and a ([beta]-diketiminate)iron(III)-imido dimer. The imido complex was formed by the N=N bond cleavage of the azobenzene substrate. Kinetic and DFT studies were performed to elucidate the mechanism of N=N bond cleavage. Chapter 4 describes two new synthetic routes to a new [beta]-diketiminate ligand with trifluoromethyl groups as electron withdrawing substituents. This ligand was used to produce low-coordinate iron complexes analogous to previously published complexes without an electron withdrawing [beta]-diketiminate ligand as an effort to ascertain the electronic effects of the [beta]-diketiminate ligand on the iron and the other coordinated ligands"--Pages viii-ix.

Download or read book Advances in Organometallic Chemistry written by Pedro J. Perez and published by Elsevier. This book was released on 2023-02-28 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Organometallic Chemistry, Volume 79, the latest release in this longstanding serial, is known for its comprehensive coverage of topics in organometallic synthesis, reactions, mechanisms, homogeneous catalysis, and more. It is ideal for a wide range of researchers involved in organometallic chemistry, with this updated release including chapters on Organometallic-like reactivity of group 10 metal-heteroatom sigma bonds, Organometallic interactions between metal nanoparticles and carbon-based molecules: a surface reactivity rationale, Group VI Allenylidene Complexes, and more. Contains contributions from leading authorities in the field of organometallic chemistry Covers topics in organometallic synthesis, reactions, mechanisms, homogeneous catalysis, and more Informs and updates readers on the latest developments in the field Carefully edited to provide easy-to-read material

Download or read book Comprehensive Organometallic Chemistry III Volume 5 written by D. M. P. Mingos and published by . This book was released on 2007 with total page 1008 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides essential information for any chemist or technologist who needs to use or apply organometallic compounds. Provides a comprehensive overview of recent developments in the field and attempts to predict trends in the field over the next ten years.