Catalytic Arene H/D Exchange with Novel Rhodium and Iridium Complexes

Abstract

Three novel pendant acetate complexes, [Rh(bdmpza)Cl 3 ] − M +, [Rh(bdmpza)Cl 2 (py)], and [Ir(bdmpza)Cl 3 ] − M + (bdmpza = bis(3,5-dimethylpyrazol-1-yl) acetate, M + = Li +, Na + ), were synthesized. Abstraction of halide from these complexes with silver salts yielded species capable of C–H activation of arenes. The catalytic H/D exchange reaction between benzene and trifluoroacetic acid- d was optimized, and these conditions were used to evaluate H/D exchange in other arenes. Branched alkyl substituents in alkyl aromatics showed an affinity toward deuterium exchange in the β-alkyl position only. DFT calculations were performed to determine the mechanism of H/D exchange.