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

Reaction of the dimer [Cp*IrHCl] 2 (Cp* = η 5 -C 5 Me 5 ) in benzene solution with either thiophene or benzothiophene at 90 °C in the presence of H 2 gives the hydrogenolysis products [Cp*IrCl] 2 (μ-H)(μ-SC 4 H 9 ) ( 1 ) and [Cp*IrCl] 2 (μ-H)[μ-S(C 6 H 4 )CH 2 CH 3 ] ( 2 ), respectively, in high yields. Upon further thermolysis under H 2, 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 H 2, reaction of [Cp*Ir HCl] 2 with thiophene gives an additional trinuclear product [Cp*IrCl] 3 (H)(SC 4 H 6 ) ( 3 ), which was also structurally characterized.