Hydrogenation of White Phosphorus to Phosphane with Rhodium and Iridium Trihydrides

Only one of the four P atoms of P reacts with rhodium and iridium trihydrides [(triphos)MH ] to provide phosphane [Eq. (a)]. The resulting cyclo-P fragment is efficiently scavenged by the metal fragment to give the complexes [(triphos)M(η -P )]. A mechanism accounting for the hydrogenation reaction is proposed in which the complexes [(triphos)MH(η :η -P )] and [(triphos)M(η :η -HP ] are intermediates. The latter complex contains the unprecedented hydridotetraphosphane ligand HP .