Carbene transfer reactivities of nickel(II)-N-heterocyclic carbene complexes and their applications in the synthesis of metal-NHC complexes

摘要

We describe a new synthetic procedure for transition-metal N-heterocyclic carbene complexes (NHCs). A number of Pd(II), Pt(II), Co(III), and Ru(II) complexes containing functionalized NHCs have been obtained in good to excellent yields using Ni ~(II)-NHC complexes as carbine transfer reagents. Ni ~(II)-NHC complexes are easily prepared from the direct reactions of the corresponding imidazolium salts with commercially available Raney nickel powder. The byproduct of transmetalation reactions, NiCl _2, can be easily removed by simple filtration. This study offers a new, economical, and practical synthetic method for metal-NHC complexes.