Download or read book The Chemistry of Low valent Metal Complexes Containing Ligands Capable of Pi donation written by Jennifer Diane Draper and published by . This book was released on 1998 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Utility of Low valent Niobium in Small Molecule Activation and the Study of First Row Transition Metal Complexes Supported by Tetradentate Redox Active Ligands written by Valerie Anne Williams and published by . This book was released on 2014 with total page 269 pages. Available in PDF, EPUB and Kindle. Book excerpt: The low-valent complex (silox)3NbPMe3 (silox = tBu3SiO) was synthesized and tested for reactivity towards small molecules. It was discovered that exposure to CO generated the complexes (silox)3Nb=C=C=O (3-Nb), (silox)3Nb=O (2-Nb), and [(silox)3Nb]2([mu]-C2) (4-Nb) in various ratios depending on reaction stoichiometry. The formation of [(silox)3Nb]2([mu]-CO) (5-Nb) was discovered as a byproduct in most reactions. Treatment of (silox)3NbPMe3 with potassium under a dinitrogen atmosphere afforded the dinitrogen complex (silox)3NbNNNb(silox)3 (8-Nb). Reaction of (silox)3NbCl (10-Nb) with NH3 afforded (silox)3NbIV(NH3)Cl, with ammonia binding parameters of [INCREMENT]H = 20.4 ± 2.3 kcal/mol and [INCREMENT]S = 39 ± 7 e.u. The nickel complex {dmp(PI)2}Ni (dmp(PI)2 = Me2C(CH2=Npy)2) was synthesized and subjected to chemical oxidation and reduction to synthesize a 5membered redox series. Through electronic structure study, it was determined that in these complexes the metal center typically remained NiII, with the possible exception of the cationic complex [{dmp(PI)2}Ni](OTf), and redox changes were primarily ligand-centered. The chemistry of dmp(PI)2 was extended to iron, and {dmp(PI)2}FePMe3 was synthesized. As with the nickel analogue, the complex was determined to be a MII center bound to a dianionic ligand framework, with similar redox behavior as the nickel species. A related tetradentate [beta]-diketiminate-based ligand incorporating two pyridinemethylene units, 2,4-bis[(E)-(2-pyridyl)methylideneamino]pentane (H{nn(PM)2}), was synthesized and metallated to form {nn(PM)2}FeN(TMS)2 (1-N(TMS)2). 1-N(TMS)2 could be further derivatized to form {nn(PM)2}FeX (X = Cl, N3). One of the methylene fragments of the ligand backbone was prone to facile deprotonation and allowed synthesis of {nn(PM)(PI)}FeLL' (LL' = (PMe3)2, (PMe2Ph)2, (PMe3)CO; 2LL') and {nn(PM)(PI)}FeL (L = PMe3, PMePh2, PPh3, CO; 3-L). Electronic structure studies suggested 2-LL' and 3-L existed as FeII metal centers bound to dianionic {nn(PM)(PI)}2-, with strong metal-ligand covalency in 3-L. Oxidation studies on 2(PMe3)2 showed two successive ligand-based 1e- oxidations. The same tetradentate [beta]diketiminate-based ligand was applied to other transition metals of the first row and allowed synthesis of {nn(PM)2}VCl2 (1-VCl2) and {nn(PM)2}Co (1-Co), both of which formed through unusual ligand exchange or disproportionation events, and {nn(PM)(PI)}M (M = Cr, 4-Cr; M = Ni, 4-Ni), which were generated through double deprotonation of the H{nn(PM)2} ligand.
Download or read book Transition Metal Complexes of Phosphorus Arsenic and Antimony Ligands written by Charles Andrew McAuliffe and published by John Wiley & Sons. This book was released on 1973 with total page 458 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Pyridine written by Pratima Parashar Pandey and published by BoD – Books on Demand. This book was released on 2018-07-18 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is designed and styled in order to give researchers a vast horizon about pyridine. A deep look in the structural analysis of pyridine provides a base for all the building blocks derived from it and its applications. Pyridines and pyridine moieties are found in many natural products, such as vitamins, coenzymes, alkaloids, many drugs, and pesticides. The book is divided into three parts: the first takes to the introduction, the second part deals with composition of various compounds using heterocyclic ring of pyridine, and the third part discusses about applications of pyridine compounds.
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2007 with total page 924 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Transition Metal Complexes with P N Ligands and Silylenes Synthesis and Catalytic Studies written by Eva Neumann and published by Cuvillier Verlag. This book was released on 2006-02-15 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt: The term ligand [latin, ligare = bind] has its origin in coordination chemistry. It denotes a molecule that is able to bind to a metal center in most cases via one or several free electron pairs.[1] Ligands can be described by the number of electron-pair donor atoms as monodentate, bidentate, tridentate etc. ligands. The latter are also called chelating ligands [greek, chele = (crab’s) claw]. A typical classification of ligands is according to their electronic properties. They serve either as a σ-donating, σ-donating/π-accepting, or σ,π-donating/π-accepting ligands.[2] A more practical, often encountered approach is the classification of ligands according to their donor atoms, especially when larger molecules and molecules containing heteroatoms are regarded (compare 1.2). Coordination chemistry was already established in the 19th century. In 1893 Alfred Werner suggested an octahedral arrangement of ligands coordinated to a central metal ion for many compounds. This explained, for example, the appearance and reactivity of four different cobalt(III) complexes (Figure 1.1), when CoCl2 is dissolved in aqueous ammonia and then oxidized by air to the +3 oxidation state. The formulas of these complexes can be written as depicted in Figure 1.1. Werner’s work was rewarded with the Nobel prize in 1913.[3]
Download or read book Transition Metal Complexes of Neutral eta1 Carbon Ligands written by Remi Chauvin and published by Springer. This book was released on 2009-12-18 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: Contents: Yves Canac and Remi Chauvin: Neutral eta1-carbon ligands: beyond carbon monoxide; Esteban P. Urriolabeitia: Ylide Ligands; Wolfgang Petz and Gernot Frenking: Carbodiphosphoranes and related ligands; Mareike C. Jahnke and F. Ekkehardt Hahn: Chemistry of N-Heterocyclic Carbene Ligands; Tsuyoshi Kato, Eddy Maerten, Antoine Baceiredo: Non-NHCs stable singlet carbene ligands; Victorio Cadierno, Sergio E. García-Garrido: All-Carbon-Substituted Allenylidene and Related Cumulenylidene Ligands; Victorio Cadierno, Sergio E. García-Garrido: Heteroatom-Conjugated Allenylidene and Related Cumulenylidene Ligands.
Download or read book Introduction to Metal Complex Chemistry written by M. Tsutsui and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Plenum Press series, Monographs in Inorganic Chemistry, is intended to fill an obvious need for high-level surveys of recent research in that area, particularly in matters which go beyond the traditional or classical bound aries of the subject. The study of n-bonding of hydrocarbon groups (and their derivatives) to metals is exactly that kind of subject, for it provides a new way of understanding the behavior of metals (which constitute four-fifths of all the chemical elements). In addition, n-bonding has expanded the intriguing area of organometallic chemistry threefold, bringing in all the transition metals, the lanthanides, and the actinides. So much has been discovered and developed in the area of n-bonded "complexes" of the metals that important new industrial processes based on such substances have been developed. A truly comprehensive review of all n-bonded compounds of the metals would now result in an impossibly large and expensive volume, and would require monthly revision. Instead, the present authors have wisely decided to write a survey which outlines the general aspects of preparation, properties, structure, reactions, and uses of such compounds-a survey which can serve as a textbook, but which can also lead the more experienced practitioner to the most advanced literature on the subject. They have clarified and condensed the subject by means of good organization and a liberal use of diagrams-features which will please the general reader.
Download or read book Studies of Low Valent Main Group and Transition Metal Complexes Supported by Nitrogen based Ligands written by Audra Faye Lugo 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 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 Advances in Organometallic Chemistry written by Robert C. West and published by Elsevier. This book was released on 2011-08-09 with total page 359 pages. Available in PDF, EPUB and Kindle. Book excerpt: Almost all branches of chemistry and material science now interface with organometallic chemistry - the study of compounds containing carbon-metal bonds. This widely acclaimed serial contains authoritative reviews that address all aspects of organometallic chemistry, a field which has expanded enormously since the publication of Volume 1 in 1964.Volume 56 comprises Part 1 of a themed collection of papers on "The Organotransition Metal Chemistry of Poly(pyrazolyl)borates". Provides an authoritative, definitive review addressing all aspects of organometallic chemistry Useful to researchers within this active field and is a must for every modern library of chemistry High-quality research book within this rapidly developing field
Download or read book Low Valent Late Transition Metal Complexes with Sulfoxide and Nitrogen Ligands written by Reto Dorta and published by . This book was released on 2002 with total page 123 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Oxygen Ligands in Low valent Transition Metal Complexes written by H. M. Griffiths and published by . This book was released on 1973 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Small Molecule Binding to Electrophilic Trigonal Pyramidal Platinum Palladium and Nickel written by Charlene Tsay and published by . This book was released on 2013 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chapter 1 A general introduction to the concepts and background of several types of transition metal complexes that motivate and inform the research described herein. These include a-complexes and molecular adducts of dinitrogen, dihydrogen, and carbon dioxide. Chapter 2 Trigonal bipyramidal platinum(II) complexes of the monoanionic, tetradentate, triphosphine [SiPR3 ([SiP3R]- = [(2-R2PC6H4)3Si]-; R = Ph, iPr) ligand are prepared and shown to provide access to cationic species with divergent behavior. The less electron-rich phenyl-substituted ligand renders the platinum center extremely electrophilic, leading to structurally characterized examples of weakly-donating ligands bound in the fifth, apical coordination site. Of particular interest is the structure of the toluene adduct, which suggests a possible interaction between the platinum center and an aryl C-H bond. When the ligand phosphines are instead substituted by the more electron-rich isopropyl groups, the electrophilicity of the cationic platinum is shown to be mitigated, allowing access to a four-coordinate, trigonal pyramidal platinum center. The crystallographically characterized geometry for this divalent platinum is in contrast to the canonical square planar configuration for d8, 16-electron transition metal complexes. The palladium analogue is also synthesized and shown to possess the same coordination. Chapter 3 Cationic nickel complexes of the [SiPR3] ligand are synthesized and, in contrast to their platinum and palladium congeners, facilitate the surprising binding of molecular dinitrogen to electrophilic nickel(II) centers. The extremely high stretching frequencies of these bound N2 moieties attest to their minimal activation, and the stability of these complexes is shown to arise from increased adonation from the N2 to the cationic nickel center, which compensates for the relative lack of it back-bonding that stabilizes N2 adducts in less electrophilic systems. These cationic nickel species are additionally shown to form thermally stable adducts of molecular dihydrogen. The relative binding strengths of N2 and H2 to these nickel centers are explored and shown to be modulated by the ligand phosphine substituents. Furthermore, evidence of linear binding of carbon dioxide is presented, representing an electrophilic approach to carbon dioxide activation that is in contrast to the low-valent, nucleophilic metal paradigm. Chapter 4 The four-coordinate neutral nickel boratrane (TPiPrB = (2-iPr2PC6H4)3B) reported in the literature represents an isostructural counterpart to the cationic {[SiiPr3]Ni}+ species presented in Chapter 3. Though these two compounds are formally separated by two oxidation states of nickel, the Lewis-acidic nature of the Z-type borane ligand in (TP'PrB)Ni renders it valence-isoelectronic with {[SiiPr3]Ni}+. The reactivity toward N2 and H2 of (TPiPr'B)Ni, as well as that of the new compound (TPPhB)Ni, is explored and discussed in context of what is observed for the {[SiPR3]Ni}+ system. The neutral (TPiPr'B)Ni, while presumably a better [pi] back-bonder than cationic {I[SiPip' 3]Ni}T, is demonstrated not to bind N2, though a very weak, fluxional interaction with H2 at low temperature is hypothesized. The more electrophilic (TP PhB)Ni exhibits room temperature interactions with both N2 and H2, though the nature of these interactions has yet to be confirmed. These results thus underline the importance of [sigma]-donation in stabilizing N2 and H2 adducts of poorly 7r back-bonding metal centers. Chapter 5 Cobalt(I) complexes of [SiPR3] provide an additional isostructural, isoelectronic point of comparison to the cationic nickel species presented in Chapter 3. The dinitrogen adducts [SiP'i' 3]Co(N2) and [SiPPh3]Co(N2), previously reported from our laboratory, feature strongly bound N2 ligands that are not labile to vacuum. The corresponding dihydrogen adducts are generated slowly under an H2 atmosphere. The intact nature of both dihydrogen ligands, which also are not labile to vacuum, is reflected in their NMR spectroscopic parameters. The thermal stability of these compounds enabled crystallization of [SiPi'' 3]Co(H2) which, along with the related (TP'i'B)Co(H2) complex also developed in our laboratory, represent the first structurally characterized dihydrogen adducts of cobalt. Additional comparisons are made between the relative N2 and H2 binding strengths of this system and those of the structurally and electronically related family of [SiPR3] and (TpRB) metal complexes. Appendix A The asymmetric dinucleating ligand [NOPPh], designed to contain both a hard, N-donor binding site and a soft-P-donor binding site, is synthesized and shown to form a diiron complex that features asymmetric bonding to the bridging acetates. The corresponding symmetric, allphosphine dinucleating ligand [POPPh], proves to be more conducive to further study, and provides access to the symmetric diiron, di-([mu]-bromide) starting material {[POPPh ]Fe 2Br2} {BArF4 }. Addition of hydrazine generates the asymmetric, unbridged N2H4 adduct, which features localized diamagnetic and paramagnetic iron centers. The conformation of this species additionally demonstrates the flexibility of this ligand framework. Reduction of the diiron(II) starting material in the presence of PMe3 results in formation of a putative asymmetric iron(O)/iron(I) dimetallic complex, in which an N2 molecule is bound to the diamagnetic iron center, while the PMe3 is ligated to the high-spin iron center and rendered NMR silent. The N2 ligand is shown to be reversibly displaced by H2 , suggesting the formation of a dihydrogen adduct, as well as by CO2, which is postulated to bind as a bent, [eta]2(C,O) ligand.
Download or read book Transition Metal Complexes of Pi Donor Ligands written by Derek Robert Wilson and published by . This book was released on 1971 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis Structure and Reactivity of Transition Metal Complexes Containing P O and N donor Ligands written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Low Valent Metal Complexes of Tris diphenylphosphinomethyl phenylborate written by Alexander B. Weberg and published by . This book was released on 2015 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt:
