Metal Complexes with Non-innocent N-donor Ligands

Metal Complexes with Non-innocent N-donor Ligands PDF Author: Marat M. Khusniyarov
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ISBN:
Category :
Languages : en
Pages : 0

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Metal Complexes with Non-innocent N-donor Ligands

Metal Complexes with Non-innocent N-donor Ligands PDF Author: Marat M. Khusniyarov
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Redox-Active Ligands

Redox-Active Ligands PDF Author: Marine Desage-El Murr
Publisher: John Wiley & Sons
ISBN: 352783088X
Category : Science
Languages : en
Pages : 373

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Book Description
Redox-Active Ligands Authoritative resource showcasing a new family of ligands that can lead to better catalysts and promising applications in organic synthesis Redox-Active Ligands gives a comprehensive overview of the unique features of redox-active ligands, describing their structure and synthesis, the characterization of their coordination complexes, and important applications in homogeneous catalysis. The work reflects the diversity of the subject by including ongoing research spanning coordination chemistry, organometallic chemistry, bioinspired catalysis, proton and electron transfer, and the ability of such ligands to interact with early and late transition metals, lanthanides, and actinides. The book is divided into three parts, devoted to introduction and concepts, applications, and case studies. After the introduction on key concepts related to the field, and the different types of ligands and complexes in which ligand-centered redox activity is commonly observed, mechanistic and computational studies are described. The second part focuses on catalytic applications of redox-active complexes, including examples from radical transformations, coordination chemistry and organic synthesis. Finally, case studies of redox-active guanidine ligands, and of lanthanides and actinides are presented. Other specific sample topics covered include: An overview of the electronic features of redox-active ligands, covering their historical perspective and biological background The versatility and mode of action of redox-active ligands, which sets them apart from more classic and tunable ligands such as phosphines or N-heterocyclic carbenes Preparation and catalytic applications of complexes of stable N-aryl radicals Metal complexes with redox-active ligands in H+/e- transfer transformations By providing up-to-date information on important concepts and applications, Redox-Active Ligands is an essential reading for researchers working in organometallic and coordination chemistry, catalysis, organic synthesis, and (bio)inorganic chemistry, as well as newcomers to the field.

Ligand Design in Metal Chemistry

Ligand Design in Metal Chemistry PDF Author: Mark Stradiotto
Publisher: John Wiley & Sons
ISBN: 1118839773
Category : Science
Languages : en
Pages : 448

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Book Description
The design of ancillary ligands used to modify the structural and reactivity properties of metal complexes has evolved into a rapidly expanding sub-discipline in inorganic and organometallic chemistry. Ancillary ligand design has figured directly in the discovery of new bonding motifs and stoichiometric reactivity, as well as in the development of new catalytic protocols that have had widespread positive impact on chemical synthesis on benchtop and industrial scales. Ligand Design in Metal Chemistry presents a collection of cutting-edge contributions from leaders in the field of ligand design, encompassing a broad spectrum of ancillary ligand classes and reactivity applications. Topics covered include: Key concepts in ligand design Redox non-innocent ligands Ligands for selective alkene metathesis Ligands in cross-coupling Ligand design in polymerization Ligand design in modern lanthanide chemistry Cooperative metal-ligand reactivity P,N Ligands for enantioselective hydrogenation Spiro-cyclic ligands in asymmetric catalysis This book will be a valuable reference for academic researchers and industry practitioners working in the field of ligand design, as well as those who work in the many areas in which the impact of ancillary ligand design has proven significant, for example synthetic organic chemistry, catalysis, medicinal chemistry, polymer science and materials chemistry.

Electronic Structure and Reactivity of Transition Metal Complexes Incorporating Pro-radical Bis-phenoxide Ligands

Electronic Structure and Reactivity of Transition Metal Complexes Incorporating Pro-radical Bis-phenoxide Ligands PDF Author: Ryan Michael Clarke
Publisher:
ISBN:
Category :
Languages : en
Pages : 194

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Book Description
Transition metal complexes with pro-radical ligands have received considerable research attention due to their interesting electronic structures, photophysical properties, and applications in catalysis. The relative ordering of metal and ligand frontier orbitals in a complex incorporating pro-radical ligands dictates whether oxidation/reduction occurs at the metal centre or at the ligand. Many metalloenzymes couple redox events at multiple metal centres or between metals and pro-radical ligands to facilitate multielectron chemistry. Owing to the simplicity of the active sites, many structural and functional models have been studied. One class of pro-radical ligand that has been investigated extensively are bis-imine bis-phenoxide ligands (i.e. salen) due to their highly modular syntheses. In this thesis, projects related to the synthesis, electronic structure, and reactivity of mono and bimetallic complexes incorporating the salen framework are explored. Chapter 2 presents a systematic investigation of the effects of geometry on the electronic structure of four bis-oxidized bimetallic Ni salen species. The tunability of their intense intervalence charge transfer (IVCT) transitions in the near infrared (NIR) by nearly 400 nm due to exciton coupling in the excited states is described. For the first time, this study demonstrates the applicability of exciton coupling to ligand radical systems absorbing in the NIR region. Chapter 3 investigates the ground-state electronic structure of a bis-oxidized Co dimer. Enhanced metal participation to the singly occupied molecular orbitals results in both high spin Co(III) and Co(II)-L• character in the ground state, and no observable band splitting in the NIR due to exciton coupling. Finally, Chapter 4 describes a series of oxidized nitridomanganese(V) salen complexes with different para ring substituents (R = CF3, tBu, and NMe2), demonstrating that nitride activation is dictated by remote ligand electronics. Upon one-electron oxidation, electron deficient ligands afford a Mn(VI) species and nitride activation, whereas an electron-rich ligand results in ligand based oxidation and resistance to N coupling of the nitrides. This study highlights the alternative reactivity pathways that pro-radical ligands impose on metal complexes and represents a key step in the use of NH3 as a hydrogen storage medium. The results presented herein provide a starting point for further efforts in reactivity with the salen platform.

Pincer Compounds

Pincer Compounds PDF Author: David Morales-Morales
Publisher: Elsevier
ISBN: 0128129328
Category : Science
Languages : en
Pages : 756

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Book Description
Pincer Compounds: Chemistry and Applications offers valuable state-of-the-art coverage highlighting highly active areas of research—from mechanistic work to synthesis and characterization. The book focuses on small molecule activation chemistry (particularly H2 and hydrogenation), earth abundant metals (such as Fe), actinides, carbene-pincers, chiral catalysis, and alternative solvent usage. The book covers the current state of the field, featuring chapters from renowned contributors, covering four continents and ranging from still-active pioneers to new names emerging as creative strong contributors to this fascinating and promising area. Over a decade since the publication of Morales-Morales and Jensen's The Chemistry of Pincer Compounds (Elsevier 2007), research in this unique area has flourished, finding a plethora of applications in almost every single branch of chemistry—from their traditional application as very robust and active catalysts all the way to potential biological and pharmaceutical applications. - Describes the chemistry and applications of this important class of organometallic and coordination compounds - Includes contributions from global leaders in the field, featuring pioneers in the area as well as emerging experts conducting exciting research on pincer complexes - Highlights areas of promising and active research, including small molecule activation, earth abundant metals, and actinide chemistry

Progress in Inorganic Chemistry, Volume 8

Progress in Inorganic Chemistry, Volume 8 PDF Author: F. Albert Cotton
Publisher: John Wiley & Sons
ISBN: 0470166592
Category : Science
Languages : en
Pages : 498

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Book Description
This comprehensive series of volumes on inorganic chemistry provides inorganic chemists with a forum for critical, authoritative evaluations of advances in every area of the discipline. Every volume reports recent progress with a significant, up-to-date selection of papers by internationally recognized researchers, complemented by detailed discussions and complete documentation. Each volume features a complete subject index and the series includes a cumulative index as well.

Reactions of Coordinated Ligands

Reactions of Coordinated Ligands PDF Author: P.S. Braterman
Publisher: Springer Science & Business Media
ISBN: 1461307554
Category : Science
Languages : en
Pages : 419

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Book Description
This, the second and final volume of Reactions of Coordinated Ligands, describes the chemistry of ligands bound through non-carbon atoms, and of coordinated carbon dioxide. As before, emphasis is on the underlying mechanisms, which provide a unity of understanding for superficially disparate processes. The wide range of topics covered illustrates well both the versatility and the usefulness of coordination chemistry in the controlled activation of ligands. Looking to the future, carbon dioxide is the feedstock of last resort. The homogeneous reduction of dinitrogen to ammonia now seems unlikely to replace the Haber process, but solution reactions also lead to more complex, varied, and valuable products. Nitrogen monoxide, a "non innocent" ligand, impinges as pollutant and reagent. Its rich chemistry stems from its linked roles as three-electron donor, and as extremely powerful -acceptor. In the hydrolysis and condensation of complexed amides, esters etc. , metals act both as templates and as tunable and poly functional Lewis acids. Here the control of hydrophobic and steric interactions begins to model the subtle mechanisms of biological specificity. Finally, phosphorus and sulfur are imporant both as ligand atoms in themselves, and as anchors for other functionalities. I would like to thank all those who have been involved in the writing and production of this work, and also my colleagues old and new, at Glasgow and the University of North Texas, for their support. Paul S. Braterman v CONTENTS 1. Reactions of Coordinated Carbon Dioxide 1 J. D. Miller 1.

SYNTHESES STRUCTURES & REACTIV

SYNTHESES STRUCTURES & REACTIV PDF Author: 李富華
Publisher: Open Dissertation Press
ISBN: 9781374727748
Category : Science
Languages : en
Pages : 244

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Book Description
This dissertation, "Syntheses, Structures and Reactivity of the Group 6 and 7 Metal Complexes Containing Chelating Nitrogen Donor Ligands and Metal-ligand Multiple Bonds" by 李富華, Fu-wa, Lee, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of thesis entitled "SYNTHESES, STRUCTURES AND REACTIVITY OF THE GROUP 6 AND 7 METAL COMPLEXES CONTAINING CHELATING NITROGEN DONOR LIGANDS AND METAL-LIGAND MULTIPLE BONDS" submitted by Lee Fu Wa for the degree of Doctor of Philosophy at the University of Hong Kong in September, 1997. ____________________________________________________________________ [Cr(CRMe )Cl ] (CRMe =meso-2,3,7,11,12-pentamethyl-3,7,11,17- 3 2 3 2+ tetraazabicyclo[11.3.1]-heptadeca-1(17),13,15-triene), [Cr(CRMe )Cl(H O)], 3 2 2+ + [Cr(CRMe )Cl(CH CN)] and [Cr(CRMe )(N )(OH)] are prepared. Upon addition 3 3 3 3 2+ 2+ of PhI=O to solutions of [Cr(CRMe )Cl(CH CN)] and [Cr(CRMe )Cl(H O)] 3 3 3 2 respectively in CH CN, the UV-visible absorption spectra of the two mixtures show similar isosbestic spectral changes attributed to the formation of V 2+ [Cr (CRMe )Cl(O)] . Addition of PhP causes the immediate recovery of 3 3 2+ [Cr(CRMe )Cl(CH CN)] as the isosbestic changes are reversed. Irradiation of 3 3 [Cr(CRMe )(N )(OH)] in acetonitrile with UV-visible light gives an azide-free 3 3 product, the FAB-MS of which shows a molecular ion peak indicative of V + + ([Cr (CRMe )(N)]ClO ). The UV-visible spectra of [Cr(CRMe )Cl ], 3 4 3 2 2+ 2+ [Cr(CRMe )Cl(H O)] and [Cr(CRMe )Cl(CH CN)] measured in water are 3 2 3 3 3+ similar to that of [Cr(CRMe )(H O) ] . Results from the conductivity measurement 3 2 2 + 2+ show that in water, [Cr(CRMe )Cl ], [Cr(CRMe )Cl(H O)] and 3 2 3 2 2+ [Cr(CRMe )Cl(CH CN)] behave as 3:1 electrolytes. The species which exists in 3 3 3+ water is likely to be the di-aquo complex [Cr(CRMe )(H O) ] . 3 2 2 2+ 2+ [Cr(CRMe )Cl(H O)] and [Cr(CRMe )Cl(CH CN)] are both found to give a 3 2 3 3 reversible oxidation couple at +1.11 V vs. SCE in aqueous solutions at pH=1 which is assigned to Cr(III)/(IV). iii t + The bis(imido) complexes [(TACN)M(N Bu) Cl] (M=Cr, Mo; TACN=1,4,7-triazacyclononane) and their 1,4,7-trimethyl derivatives are prepared, the crystal structures of which reveal the trans influence of the imido group. These 0 +/0 d species display a quasi-reversible couple at potentials 0.86 - 1.20 V vs. Cp Fe in acetonitrile assignable to a imido ligand-centred oxidation. (Me TACN)Mo(CO), 1,4,7-Tri((S)-2-methylbutyl)-1,4,7-triazacyclononane 3 3 * * * (L ) and L Mo(CO) are synthesized. (Me TACN)Mo(CO) and L Mo(CO) show 3 3 3 3 +/0 reversible oxidation couples at -0.26 V and -0.24 V vs. Cp Fe in CH CN 2 3 I/0 respectively which are assigned to Mo . The comparable electronic effect of * Me TACN and L in this system is therefore implied. 2+ [(Me TACN) Mn (μ-O)(μ-OCOCH ) ] is prepared and found to mediate 3 2 2 3 2 aziridination of styrene, methylstyrene, cis- and trans-stilbene, 1,1-diphenylethene and norbornene by PhI=NTs in CH Cl at 25 C. The nitrene transfer to cis- and 2 2 trans-stilbene is found to be stereoselective to exclusively give the trans-aziridine product. + + [(Me TACN)(CO) M CPh] (M=Mo, W) and [(TACN)(CO) Mo CPh] 3 2 2 are prepared. [(Me TACN)(CO) M CPh] (M=Mo, W) exhibit a reversible 3 2 +/0 reduction couple at -2.15 V vs Fe Cp and an irreversible wave at 0.77 V vs +/0 Fe Cp, which are ascribed to a reduction centred at the phenyl ring and oxidation of the terminal CO respectively. Treatment of Cl(

Synthesis, Structure and Reactivity of Transition Metal Complexes Containing P-, O- and N-donor Ligands

Synthesis, Structure and Reactivity of Transition Metal Complexes Containing P-, O- and N-donor Ligands PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Vanadium Catalysis

Vanadium Catalysis PDF Author: Manas Sutradhar
Publisher: Royal Society of Chemistry
ISBN: 1839160896
Category : Science
Languages : en
Pages : 526

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Book Description
Vanadium is one of the more abundant elements in the Earth’s crust and exhibits a wide range of oxidation states in its compounds making it potentially a more sustainable and more economical choice as a catalyst than the noble metals. A wide variety of reactions have been found to be catalysed by homogeneous, supported and heterogeneous vanadium complexes and the number of applications is growing fast. Bringing together the research on the catalytic uses of this element into one essential resource, including theoretical perspectives on proposed mechanisms for vanadium catalysis and an overview of its relevance in biological processes, this book is a useful reference for industrial and academic chemists alike.