Cooperative Molybdenum-Thiolate Reactivity for Transfer Hydrogenation of Nitriles

A half-sandwich molybdenum­(II) thiolate complex with a η2-MeCN ligand, Cp*Mo­(1,2-Ph2PC6H4S)­(η2-NCMe) (1(η2-NCMe)), was found to catalyze transfer hydrogenation of nitriles efficiently with ammonia borane (H3N·BH3) at room temperature, producing primary amines. Through molybdenum-thiolate cooperation, the B–H bond of BH3 is cleaved, affording a Mo­(II)-H hydride (1H­(BH2)) with the BH2 moiety captured at the S–Mo unit. In the presence of NH3, 1H­(BH2) smoothly achieves the catalytic transfer hydrogenation of nitriles.