Reactions of Cp*Ir(2,5-dimethylthiophene) with electrophiles, acids, and maleic anhydride

This paper describes reactions of the two isomers (η5-Cp*)Ir(η4-2,5-Me2T) (1) and (η5-Cp*)Ir(C,S-2,5-Me2T) (2), where 2,5-Me2T is 2,5-dimethylthiophene, with several electrophiles, acids, and maleic anhydride. The reactions of 1 and 2 with methyl iodide give the same product Cp*Ir(η4-2,5-Me2T·CH3)+ in which the CH3+ is bonded to the sulfur atom, as established by X-ray studies. The reaction of 1 with maleic anhydride gives two structurally characterized products: Cp*Ir[η1(S)-Cp*Ir(η4-2,5-Me2T)][η2-C4H2O3] (13), in which S-coordinated Cp*Ir(η4-2,5-Me2T) and η2-maleic anhydride are ligands to the Cp*Ir unit, and another product (12) that has the composition of 13 except for one additional oxygen atom. Complex 12, with a complicated and unusual structure, is also isolated from the reaction of maleic anhydride and the acylthiolate Cp*Ir[η4-C3H2MeC(O)Me] (14). Reactions of 1 and 2 with a variety of other agents (MeSSMe2+, CF3SO3H, HCl, H2S, EtOH and I2) are also described.