Chloride abstraction from chloroaminophosphido complexes of molybdenum, tungsten, and ruthenium leads to the terminal aminophosphinidene complexes [Cp*(CO)3Mo(PNiPr2)][AlCl4] (3), [Cp*(CO)3W(PNiPr2)][AlCl4] (4), and [Cp*Ru(CO)2(PNiPr2)][AlCl4] (6). These are the first structurally characterized examples of heteroatom-substituted phosphinidene complexes, and 6 is the first example of a late transition metal phosphinidene complex.

Reaction of the electrophilic phosphinidene complex [Cp*Mo(CO) 3 {PN i Pr 2 }][AlCl 4 ] with triethylphosphine results in reversible coordination of the phosphine to the phosphinidene phosphorus atom followed by carbonyl displacement at the metal. Phosphine-coordinated phosphinidene complexes with P-P bonds can be isolated by using diphosphines which coordinate first to the phosphinidene and then chelate to the phosphinidene and metal atoms.