Modeling aspects of hydrodesulfurization by molybdenum hydride compounds: Desulfurization of thiophene and benzothiophene and C–S bond cleavage of dibenzothiophene

Abstract

The molybdenum hydride complexes Mo(PMe 3) 5H 2 and Mo(PMe 3) 4H 4 are capable of cleaving the C–S bonds of thiophene, benzothiophene and dibenzothiophene. For example, Mo(PMe 3) 5H 2 reacts with thiophene to give the η 5-thiophene and butadiene–thiolate complexes, (η 5-C 4H 4S)Mo(PMe 3) 3 and (η 5-C 4H 5S)Mo(PMe 3) 2(η 2-CH 2PMe 2). These complexes are also obtained from the reaction between Mo(PMe 3) 4H 4 and thiophene under photochemical conditions, whereas at elevated temperatures thiophene is desulfurized to liberate but-1-ene. Similarly, Mo(PMe 3) 4H 4 desulfurizes benzothiophene at elevated temperatures to liberate ethylbenzene, while the arylthiolate complex Mo(PMe 3) 4(SC 6H 4Et)H 3 is obtained photochemically. Furthermore, Mo(PMe 3) 4H 4 cleaves the C–S bond of dibenzothiophene to give [η 6,κ 1-C 6H 5C 6H 4S]Mo(PMe 3) 2H.