Reaction of Terminal Phosphinidene Complexes with Dihydrogen

The reaction of H2 with [RP-W(CO)5] (R = Ph, Me) above 120 °C leads, first, to the secondary diphosphine complex (RPH-PHR)(W(CO)5)2 and then to the primary phosphine complex (RPH2)(W(CO)5). On the basis of DFT calculations, the mechanism most likely involves the addition of H2 to the P–W bond, followed by the formation of the radical [RPH-W(CO)5]• by homolysis of the W–H bond. In the case of [PhNHP-W(CO)5], the hydrogenolysis takes place at the P–N bond and ultimately produces the secondary diaminophosphine complex ((PhNH)2PH)(W(CO)5).