Reversibility of 1,4-Metal Migration in Cp~*RhIII and Cp~*IrIII Complexes

摘要

The (2-ethenyl-4-methylphenyl)arylrhodium complex[Cp~*Rh{C_6H_3-2-(C(Ph)≡CHPh)-4-Me}(PMe_3)][BAr_4~F], which is formed from the vinyl-to-aryl 1,4-Rh migration of the 2-(mtolyl) ethenyl complex [Cp~*Rh{C(Ph)≡C(C_6H_4Me-m)Ph}-(PMe_3)][BAr_4~F], is isomerized under mild conditions to the regioisomeric 2-ethenylphenyl complex [Cp~*Rh{C_6H_4-2-(C-(C_6H_4Me-m)≡CHPh)}(PMe_3)][BAr_4~F] by way of a back-reaction to regenerate the 2-(m-tolyl)ethenyl complex intermediate followed by the rotation of the C≡C bond and the second 1,4-Rh migration, providing experimental evidence for the reversibility of the vinyl-toaryl 1,4-metal migration.