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

Three novel pendant acetate complexes, [Rh­(bdmpza)­Cl3]−M+, [Rh­(bdmpza)­Cl2(py)],
and [Ir­(bdmpza)­Cl3]−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.