Synthesis, Structures of Benzoxazolyl Iridium(III) Complexes, and Applications on C–C and C–N Bond Formation Reactions under Solvent-Free Conditions: Catalytic Activity Enhanced by Noncoordinating Anion without Silver Effect

Several
new bisbenzoxazolyl iridium­(III) complexes have been synthesized
and characterized through X-ray crystallography. These complexes exhibit
excellent catalytic activity in C–C and C–N bond formation
reactions from the alkylation of amine with amine, amine with alcohol,
ketone with alcohol, and alcohol with alcohol through a borrowing
hydrogen reaction. Moreover, these iridium­(III) complexes are effective
catalysts for the alkylation of amine with alcohol and ketone with
alcohol under solvent-free conditions. The catalytic activity of these
complexes is greatly enhanced by noncoordinating, while the experiments
have excluded the possibility of a “silver effect” (bimetallic
catalysis or silver-assisted metal catalysis) from the experiments.