Thiophene and Butadiene−Thiolate Complexes of Molybdenum:  Observations Relevant to the Mechanism of Hydrodesulfurization

Abstract

Mo(PMe3)6 reacts with thiophene to give the η5-thiophene complex (η5-C4H4S)Mo(PMe3)3 and the η5-butadiene−thiolate complex (η5-C4H5S)Mo(PMe3)2(η2-CH2PMe2), which are the first examples of (i) η5-thiophene coordination and (ii) C−S cleavage and hydrogenation by a molybdenum compound. Deuterium labeling studies suggest that the hydrogenation of thiophene may involve an alkylidene intermediate, an observation that has ramifications for the mechanisms of hydrodesulfurization.