N-Heterocyclic Carbenes in Transition Metal Catalysis

N-Heterocyclic Carbenes in Transition Metal Catalysis
Author: Frank Glorius
Publisher: Springer Science & Business Media
Total Pages: 241
Release: 2007
Genre: Science
ISBN: 3540369295

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.

N-Heterocyclic Carbenes in Transition Metal Catalysis and Organocatalysis

N-Heterocyclic Carbenes in Transition Metal Catalysis and Organocatalysis
Author: Catherine S.J. Cazin
Publisher: Springer Science & Business Media
Total Pages: 348
Release: 2010-10-04
Genre: Science
ISBN: 9048128668

N-Heterocyclic Carbenes in Transition Metal Catalysis and Organocatalysis features all catalytic reactions enabled by N-heterocyclic carbenes (NHCs), either directly as organocatalysts or as ligands for transition metal catalysts. An explosion in the use of NHCs has been reported in the literature during the past seven years making this comprehensive overview highly apropos. The book begins with an introductory overview of NHCs which could have been subtitled all you need to know about NHCs. The main body of the book is dedicated to applications of NHCs in catalysis. In addition to the success stories of NHCs in metathesis, NHCs in cross coupling and more recently NHCs in organocatalysis, all other less publicized areas are also covered. As the success of NHCs is generally attributed to their potential to stabilize metal centres, the inclusion of a chapter on the decomposition of NHC catalysts is pertinent. The book closes with a chapter describing the applications of NHCs in industrial processes, which is the first coverage of its kind, and brings a unique industrial context to this book. Included in this book: Historical aspects of NHCs Synthetic pathways to NHC precursors, free NHCs and complexes Methods of characterisation of NHCs and related complexes Electronic properties of NHCs Steric properties of NHCs and models for their description NHCs for metathesis and cross-coupling reactions NHCs as organocatalysts NHC Transition-Metal mediated oxidations, additions to multiple bonds, polymerisation and oligomerisation, cyclisations, direct arylations, reactions involving CO, C-F and C-H bond activation, ... Decomposition of NHC-containing catalysts Industrial applications involving NHC-containing catalysts N-Heterocyclic Carbenes in Transition Metal Catalysis and Organocatalysis provides a fresh view of NHCs since most contributors are young emerging researchers in the field of homogeneous catalysis using NHCs. This group of contributors is complemented by highly established academic researchers and an industrialist. This book is comprehensive, from the basic features of NHCs to the latest advances, hence it is suitable for both the novice and the expert.

The Organometallic Chemistry of N-heterocyclic Carbenes

The Organometallic Chemistry of N-heterocyclic Carbenes
Author: Han Vinh Huynh
Publisher: John Wiley & Sons
Total Pages: 334
Release: 2017-04-17
Genre: Science
ISBN: 1118593774

The Organometallic Chemistry of N-heterocyclic Carbenes describes various aspects of N-heterocyclic Carbenes (NHCs) and their transition metal complexes at an entry level suitable for advanced undergraduate students and above. The book starts with a historical overview on the quest for carbenes and their complexes. Subsequently, unique properties, reactivities and nomenclature of the four classical NHCs derived from imidazoline, imidazole, benzimidazole and 1,2,4-triazole are elaborated. General and historically relevant synthetic aspects for NHCs, their precursors and complexes are then explained. The book continues with coverage on the preparation and characteristics of selected NHC complexes containing the most common metals in this area, i.e. Ni, Pd, Pt, Ag, Cu, Au, Ru, Rh and Ir. The book concludes with an overview and outlook on the development of various non-classical NHCs beyond the four classical types. Topics covered include: Stabilization, dimerization and decomposition of NHCs Stereoelectronic properties of NHCs and their evaluation Diversity of NHCs Isomers of NHC complexes and their identification NMR spectroscopic signatures of NHC complexes normal, abnormal and mesoionic NHCs The Organometallic Chemistry of N-heterocyclic Carbenes is an essential resource for all students and researchers interested in this increasingly important and popular field of research.

Late Transition Metal Complexes Incorporating Hemilabile Mixed-donor N-heterocyclic Carbene Ligands

Late Transition Metal Complexes Incorporating Hemilabile Mixed-donor N-heterocyclic Carbene Ligands
Author:
Publisher:
Total Pages:
Release: 2004
Genre:
ISBN:

The discovery of N-heterocyclic carbenes (NHC) has dramatically affected the world of catalysis. Their inherent properties that make them excellent auxiliary ligands for catalytic processes have countless laboratories worldwide probing and exploiting every notable feature they possess. However, while there is no shortage of attention in this field of research, there has been considerably less interest in NHCs with an ability chelate to metals via a mixed-donor ligand architecture. Thus, this thesis describes the synthesis and application of a ligand set comprised of bidentate mixed-donor NHC ligands. The ligands prepared all contain a mesitylimidazol-2-ylidene core unit, but incorporate different donor-functionalized tethers. These mixed-donor NHC ligands are synthesized by using a strong base, such as KN(SiMe3)2, to deprotonate the imidazolium salt precursors. This strategy was used to effectively prepare 1-mesityl-3-(2-(mesitylamino)ethyl)imidazol-2-ylidene, Mes[CNH] and 1-mesityl-3-(2-aminoethyl)imidazol-2-ylidene, Mes[CNH2]. Mes[CNH] was found to be a convenient proligand for the synthesis of various M-NHC (M = Rh, Ir, Ru, Pd, Ni, Fe, Ag, Li) compounds. These Mes[CNH]-M complexes demonstrated the hemilabile character of the Mes[CNH] ligand forming complexes that incorporated either a coordinated or uncoordinated amino tether. Mes[CNH]M(diene)Cl, Mes[CN]M(diene) and [Mes[CNH]M(diene)]BF4(M = Rh, Ir; diene = 1,5-cyclooctadiene, 2,5-norbornadiene) were synthesized and investigated for their ability to perform hydrogenation and hydrosilylation reactions with various substrates. Mes[CNH]Ru(=CHPh)(PCy3)Cl2, Mes[CNH]Ru(=CHPh)(py)Cl2 (py = pyridine) and Mes[CNH]Ru(=CHPh)(PMe3)Cl2 were also synthesized and fully characterized. The activity of the former two Ru complexes was studied for their ability to catalyze ring-closing metathesis (RCM) and ring-opening metathesis polymerization (ROMP) reactions. In addition, the phosphine dissociation rate of Mes[CNH]Ru(=CHPh)(PCy3).

Transition Metal Complexes of N-heterocyclic Carbenes and Derivatives Thereof

Transition Metal Complexes of N-heterocyclic Carbenes and Derivatives Thereof
Author: Timothy Gordon Larocque
Publisher:
Total Pages:
Release: 2013
Genre:
ISBN:

N-heterocyclic carbenes (NHCs) have played a dominant role in organometallic chemistry for decades and revolutionized the field of homogenous catalysis. NHCs have been thoroughly studied, both experimentally and theoretically, and have shown unique reactivity towards transition metals, chalcogens, azides and pnictogens. This thesis is aimed at utilizing the unique reactivity of N-heterocyclic carbenes to develop novel, robust catalysts to mediate organic transformations. The multi-faceted work within this thesis explores the use of NHCs as ancillary ligands on early and late transition metals as potential catalysts for olefin polymerization and ring-closing metathesis, respectively. This work also includes exploring the synthesis and coordination of ancillary ligands derived from the unique reactivity of NHCs towards azides, chalcogens and pnictinidenes. The reactivity of a novel aryl-substituted acyclic imino-N-heterocyclic carbene to early transition metals, cyclooctasulfur and Grubbs-type ruthenium benzylidene complexes was explored. The reactivity of imidazol-2-imide towards Grubbs-type ruthenium benzylidene complexes and the synthesis and coordination of a novel group of ligands bearing an imidazol-2-imine scaffold were also explored. Lastly, this work will include the reactivity of IMes=PPh to Grubbs-type ruthenium benzylidene complexes.