Photochemical generation of reactive transition-metal intermediates from air-stable precursors. Carbon-hydrogen bond activation via near-ultraviolet photolysis of Cp*Ir(L)(oxalate) and Cp*Ir(L)(N3)2 complexes

Abstract

We have synthesized several new oxalate and azide complexes of the form Cp*Ir(Ox)L (Cp*=pentamethylcyclopentadienyl, Ox=oxalate and L=P(Me) 3 , P(Cy) 3 ) and Cp*Ir(N 3 ) 2 L (L=P(Me) 3 , P(Ph) 3 , P(Cy) 3 , and t-BuNC) respectively. Upon photolysis, these complexes undergo reactions that result in the elimination of CO 2 or N 2 to give reactive intermediates that undergo net oxidative-addition reactions with C−H and C−Cl bonds. We have observed either intermolecular (reaction with solvent) or intramolecular (reaction with a ligand bond) oxidative addition to the Ir center. For photolysis of the azide complexes in benzene solutions, the mode of reaction is determined by L