Mild P4 Activation To Give an Anionic Diphosphorus Complex with a Dual Binding Ability at a Single P Site

The anion [Mo2Cp2(μ-PCy2)(μ-CO)2]− (1; Li+ salt) reacts at 290 K with P4 to give the diphosphorus-bridged complex [Mo2Cp2(μ-PCy2)(CO)2(μ-κ2:κ2-P2)]− (2). The latter reacts with MeI and ClSnPh3 through a single P atom to give respectively diphosphenyl [Mo2Cp2(μ-PCy2)(CO)2(μ-κ2:κ2-P2Me)] (3) and stannyl [Mo2Cp2(μ-PCy2)(CO)2{μ-κ2:κ2-P2(SnPh3)}] (4) derivatives, with the P−P−Sn angle in 4 being unexpectedly acute [80.3(1)°]. According to density functional theory calculations, this novel nucleophilic behavior of 1 is derived from its anionic nature, thus enabling the P2 ligand to act in a π-donor-like fashion.