Download or read book Early Transition Metal Complexes Containing Tridentate Amido Ligands written by Lan-Chang Liang and published by . This book was released on 1999 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Transition Metal Complexes Containing Chelating Amido Ligands written by Scott William Seidel and published by . This book was released on 1998 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis and Characterization of Tridentate Amido Ligand Derivatives of Early Transition metals written by Abdul-Razak Habib Al-Soudani and published by . This book was released on 1993 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis and Characterization of Tridentate Amido Ligand Derivaties of Early Transition metals written by Abdul-Razak Habib Al-Soudani and published by . This book was released on 1992 with total page 548 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Early Transition Metals written by David L. Kepert and published by . This book was released on 1972 with total page 520 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Early Transition Metal Complexes Containing Sterically Demanding Ligands and Reactive delta bonds written by John Gavenonis and published by . This book was released on 2003 with total page 546 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis and Reactivity of Early Transitional Metal Complexes Supported by Sterically Demanding Amido Ligands written by Marc John Andrew Johnson and published by . This book was released on 1998 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis and Reactivity of Early Transition Metal Complexes Containing Multiple Metal to Carbon Nitrogen Or Oxygen Bonds written by Scott M. Rocklage and published by . This book was released on 1982 with total page 386 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Oxidation State Roulette written by Brandon Fitchett and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of rare and expensive noble metals in the chemical industry as organometallic catalysts has grown exponentially in the past few decades due to their high activity, selectivity and their ability to catalyze a wide range of reactions. With this growth in use has also come a proportional growth in concern as these toxic metals inevitably leach into the environment and their negative effects on public health and our ecosystems are becoming better understood. First-row transition metal catalysts provide both environmental and economic benefits as alternatives to these noble metals due to their lower toxicity and cheaper costs. The two-electron chemistry that makes the noble metals so attractive however, is more challenging to accomplish with first-row transition metals. Intelligently designing the ligand scaffold which surrounds the metal can mitigate or even eliminate some of the shortfalls of these first-row metals. Some key features that should be considered when designing a ligand are: 1) a strong chelating ability so the ligand can stay attached to the metal, 2) incorporation of strong donors to favour low-spin complexes, 3) inclusion of hemilabile groups to allow for substrate activation and metal stabilization throughout various oxidation states, 4) redox activity to be able to donate or accept electrons, and 5) inclusion of Lewis base functionalities which are able to assist the substrate activation. Ligands which incorporate these features are known as bifunctional ligands as they can accomplish more than one function in the catalytic cycle. Developing first-row transition metal complexes containing these ligands may enable these species to replicate the reactivity and selectivity generally associated with the precious metals. Being able to replace the noble metals used in industry with these catalysts would have tremendous environmental and economic benefits. The objective of this thesis is to advance the field of bifunctional catalysis by examining the behaviour of two sterically svelte, tridentate SNS ligands containing hard nitrogen and soft sulphur donors when bonded to cobalt. Previous work with iron provides a template of the ligand behaviour to which cobalt can be compared, allowing us to contrast the effects exerted by the different metals. After an introduction to bifunctional catalysis in Chapter 1, Chapter 2 describes the reactivity of the amido ligand, SMeNHSMe, with precursors ranging from Co(I) to Co(III), all of which yielded the 19e- pseudooctahedral cobalt(II) bis-amido complex, Co(SMeN-SMe)2 characterized by 1H NMR spectroscopy, single-crystal X-ray crystallography and cyclic voltammetry. Although this complex has a similar structure as the Fe analogue, the cobalt bis-amido complex did not exhibit the same hemilabile behaviour that allowed for simple ligand substitution of one of the thioether groups. Instead it reacted reversibly with 2,2'-bipyridine while 1,2-bis(dimethylphosphino)ethane (DMPE) and 2,6-dimethylphenyl isocyanide both triggered additional redox chemistry accompanied by the loss of protonated SMeNHSMe. In contrast, protonation gave the cobalt(II) amido-amine cation, [Co(SMeNSMe)(SMeNHSMe)](NTf2), which allowed for substitution of the protonated ligand by acetonitrile, triphenylphosphine and 2,2'-bipyridine based on 1H NMR evidence. The ability of Co(SMeNSMe)2 to act as a precatalyst for ammonia-borane dehydrogenation was also probed, revealing that it was unstable under these conditions. Addition of one equivalent of DMPE per cobalt, however, resulted in better activity with a preference for linear aminoborane oligomers using ammonia-borane and, surprisingly, to a change in selectivity to prefer cyclic products when moving to methylamine-borane. Chapter 3 delves into the chemistry of the thiolate ligand, SMeNHS, which formed a new 18e- cobalt(III) pseudooctahedral complex, Co(S-NC-)(SMe)(DEPE), from oxidative addition of the Caryl-SMe bond. Scaling up this reaction resulted instead in formation of an imine-coupled [Co(N2S2)]- anion which was characterized by 1H NMR/EPR spectroscopy, single-crystal X-ray diffraction, cyclic voltammetry and DFT studies. The latter revealed an interesting electronic structure with two electrons delocalized in the ligand, demonstrating the non-innocent nature of the N2S2 ligand. While the analogous iron complex proved to be an effective pre-catalyst for the hydroboration of aldehydes with selectivity against ketones, this behaviour was not observed with [Co(N2S2)]- which gave a slower rate and less selectivity. The knowledge acquired from this thesis work has advanced the field of bifunctional catalysis by extending the application of these two SNS ligands from iron to cobalt, revealing unpredictable differences in reactivity between the metals. By comparing the behaviour of these ligands with iron and cobalt, we gain a better understanding of the chemistry that is accessible by these ligands and the applications for which they may be used. This increased knowledge contributes to our long-term goal of replacing expensive and toxic noble metals with more benign first-row transition metals, improving the sustainability of the chemical industry.

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 Low coordinate First Row Early Transition Metal Complexes Stabilized by Modified Terphenyl Ligands written by Jessica Nicole Boynton and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The research in this dissertation is focused on the synthesis, structural, and magnetic characterization of two-coordinate open shell (d1-d4) transition metal complexes. Background information on this field of endeavor is provided in Chapter 1. In Chapter 2 I describe the synthesis and characterization of the mononuclear chromium (II) terphenyl substituted primary amido complexes and a Lewis base adduct. These studies suggest that the two-coordinate chromium complexes have significant spin-orbit coupling effects which lead to moments lower than the spin only value of 4.90 [mu]B owing to the fact that [lambda] (the spin orbit coupling parameter) is positive. The three-coordinated complex 2.3 had a magnetic moment of 3.77 [mu]B. The synthesis and characterization of the first stable two-coordinate vanadium complexes are described in Chapter 3. The values suggest a significant spin orbital angular momentum contribution that leads to a magnetic moment that is lower than their spin only value of 3.87 [mu]B. DFT calculations showed that the major absorptions in their UV-Vis spectra were due to ligand to metal charge transfer transitions. The titanium synthesis and characterization of the bisamido complex along with its three-coordinate titanium(III) precursor are described in Chapter 4. Compound 4.1 was obtained via the stoichiometric reaction of LiN(H)AriPr 6 with the Ti(III) complex TiCl3 *2NMe3 in trimethylamine. The precursor 4.1 has trigonal pyramidal coordination at the titanium atom, with bonding to two amido nitrogens and a chlorine as well as a secondary interaction to a flanking aryl ring of a terphenyl substituent. Compound 4.2 displays a very distorted four-coordinate metal environment in which the titanium atom is bound to two amido nitrogens and to two carbons from a terphenyl aryl ring. This structure is in sharp contrast to the two-coordinate linear structure that was observed in its first row metal (V-Ni) analogs. The synthesis and characterization of mononuclear chromium(II) terphenyl primary substituted thiolate complexes are described in Chapter 5. Reaction of the terphenyl primary thiolate lithium derivatives LiSAriPr4 and LiSArMe6 with CrCl2THF2 in a 2:1 ratio afforded complexes 5.1 and 5.2, which are the very rare examples of chromium(II) thiolates with quasi-two-coordination at the metal center. Both deviate from linearity and have S-Cr-S angles of 111.02(3)° and 107.86(3)° with secondary Cr-C(aryl ring) interactions of ca. 2.115 Å and 1.971 Å respectively. The initial work on titanium and vanadium terphenyl thiolates is described in Appendix I and II. In Chapter 6 I show that the reaction of K2COT (COT= 1,3,5,7-cyclooctatetraene, C8H8) with an aryl chromium(II) halide gave (CrAriPr4)2([mu]2-n3:n4-COT) (6.1) in which a non-planar COT ring is complexed between two CrAriPr4 moieties -- a configuration previously unknown for chromium complexes of COT. OneCr2+ ion is bonded primarily to three COT carbons (Cr--C= 2.22-2.30 Å ) as well as an ipso carbon (Cr-C= ca. 2.47 Å) from a flanking aryl ring of its terphenyl substituent. The other Cr2+ ion bonds to an ipso carbon (Cr-C= ca. 2.53 Å) from its terphenyl substituent as well as four COT carbons (Cr--C= 2.24-2.32 Å). The COT carbon-carbon distances display an alternating pattern, consistent with the non-planarity and non-aromatic character of the ring. The magnetic properties of 6.1 indicate that the Cr2+ ions have a high-spin d4 configuration with S = 2. The temperature dependence of the magnetism indicates that their behavior is due to zero-field splitting of the S = 2 state. Attempts to prepare 6.1 by the direct reaction of quintuple-bonded (CrAriPr4)2 with COT were unsuccessful. (Abstract shortened by UMI.) --Proquest.

Download or read book Transition Metal Complexes of Tridentate Ligands Containing Phosphorus Arsenic and Sulfur Donor Atoms written by Marcus Orrin Workman and published by . This book was released on 1966 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Transition Metal Complexes of Tridentate Ligands written by Donald Saunders Litster and published by . This book was released on 1976 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis Characterization and Reactivity of Transition Metal Complexes Containing Multi donor Ligands written by John C. Linehan and published by . This book was released on 1986 with total page 514 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Synthesis of Novel Transition Metal Complexes Containing Amidinato Ligands written by David John Maloney and published by . This book was released on 1995 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Late Transition Metal Complexes Containing Tridentate Pincer type 1 3 bis o diphenylphosphino Phenyl N N heterocyclic Phosphenium carbene Ligands written by Baofei Pan and published by . This book was released on 2006 with total page 175 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis and Structures of Transition Metal Complexes Derived from a Pentafluorophenyl Substituted 2 pyridyl Amido Ligand written by Yin Man Lai and published by . This book was released on 2009 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt: