Synthesis and catalytic activities of Ni complexes bearing a novel N–C–N pincer ligand containing NHC with a bicyclic motif

Abstract A novel N–C–N pincer ligand bearing an NHC with a bicyclic framework, namely NHC(CH2Py)2, was developed and successfully applied to the syntheses of air- and moisture-stable silver and nickel complexes. The silver complex was identified as {[NHC(CH2Py)2]2Ag}+(AgCl2)–, and the AgCl2 anion was coordinated with one of four pyridines. Transmetallation from silver to nickel using NiCl2(PPh3)2 in toluene and a subsequent anion exchange gave us {[NHC(CH2Py)2]NiCl}+(PF6)– and {[NHC(CH2Py)2]NiCl}+(BF4)– in good yields. These complexes were active and highly stable catalysts when used for Kumada-Tamao-Corriu coupling between 3-bromo-/3-chloropyridine and PhMgBr.