NHC-Cobalt, Rhodium and Iridium Complexes in Catalysis

VINCENT CESAR,LUTZ H. GADE AND STEPHANE BELLEMIN-LAPONNAZ  

Laboratoire de Chimie de Coordination du CNRS, 205 route de Narbonne, 31077 Toulouse Cedex 4, France Anorganisch-Chemisches Institut, Universitat Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany Institut de Physique et Chimie des Materiaux de Strasbourg, CNRS-Universite de Strasbourg, 23 Rue du Loess, 67034 Strasbourg, France 

This Chapter is devoted to the development of cobalt-, rhodium- and iridium-based catalysts that contain N-heterocyclic carbene (NHC) ligands. It will cover their most relevant catalytic applications, along with stoichiometric model reactions, except for catalytic oxidations and reductions such as hydrogenations, hydrosilylations and hydroborations, which are treated in detail in Chapters 12 and 13. Since the NHC chemistry of Group 9 metals is one of the most developed areas in this field, this overview will only cover the chemistry of classical NHCs, namely cyclic diaminocarbenes. Chapter 5 reviews the chemistry of the non-classical NHCs, to which the reader is referred. Finally, this Chapter does not pretend to be exhaustive and further details may be found in previous overviews.  

The N-heterocyclic carbene complexes of cobalt have been less studied than their heavier analogues, rhodium and iridium, even though NHC-cobalt complexes have been known for more than 3 decades. Despite the fact that their 

N-Heterocyclic Carbenes From Laboratory Curiosities to Effldent Synthetic Tools 

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