Hydrodesulfurization of Thiophene and Benzothiophene to Butane and Ethyl Benzene by a Homogeneous Iridium Complex

Reaction of the dimer [Cp*IrHCl]2 (Cp* ) η5-C5Me5) in benzene solution with either thiophene or benzothiophene at 90 °C in the presence of H2 gives the hydrogenolysis products [Cp*IrCl]2(μ-H)(μ-SC4H9) (1) and [Cp*IrCl]2(μ-H)[μ-S(C6H4)CH2CH3] (2), respectively, in high yields. Upon further thermolysis under H2, the completely desulfurized products, butane and ethylbenzene, can be made. Complexes 1 and 2 were characterized by single-crystal X-ray diffraction. In the absence of H2, reaction of [Cp*Ir HCl]2 with thiophene gives an additional trinuclear product [Cp*IrCl]3(H)(SC4H6) (3), which was also structurally character- ized.