Photoinduced C-H activation and catalytic carbonylation of benzene - New features of a tris(pyrazolyl)methanesulfonato (Tpms) rhodium(I) complex

Irradiation of [(Tpms)Rh(CO)(PMe3)] (1) in benzene or [D-6]benzene affords the rhodium(III) compounds [(Tpms)Rh(H)(C6H5)(PMe3)] (2) and [(Tpms)Rh(D)(C 6D5)(PMe3)] (2-d(6)) respectively. The k(H)/k(D) ratio for the formation of 2 and 2-d(6) was found to be 1.1. The complexes 2 and 2-d(6) are stable in protic solvents. When a solution of 1 in benzene is irradiated under carbo n monoxide pressure, benzaldehyde is formed catalytically with turnover num bers of up to 20. The formation of 2 and [(Tpms)Rh(H)(COC6H5)(PMe3)] (4) un der catalytic conditions allows the proposal of a catalytic cycle.