Dinuclear Iridium Complexes Containing Cp* and Carbonyl Ligands: Synthesis, Structure, and Reactivity

The syntheses of the monomeric cationic complexes [Cp*(CO)Ir(R)(CH2Cl2)] were attempted (Cp* = η5-C5Me5, R = Me, H). The target complexes were not obtained; instead, dimeric products were isolated in high yields. The reaction between Cp*(CO)Ir(Me)Cl and [Li(Et2O)2.5][BArF4] afforded the cationic complex [{Cp*(CO)Ir(Me)}2(μ-Cl)][BArF4] (4) in high yield. Complex 4 has been characterized by 1H NMR, 13C{1H} NMR, and IR spectroscopies. Reaction of Cp*(CO)Ir(H)2 with [CPh3][BArF4] produced the dicationic complex [Cp*(CO)Ir(μ-H)]2[BArF4]2 (9) in excellent yield. Complex 9 has been characterized by 1H NMR and IR spectroscopies as well as elemental analysis and single-crystal X-ray diffraction. An X-ray structural determination was also carried out on the related complex [Cp*(Cl)Ir(μ-H)]2 (14). The solid-state structures of 9 and 14 are compared briefly.