Reaction of Li/Cl phosphinidenoid complexes with a phosphite substituted ketone: access to complexes with a novel mixed-valence polycyclic P,C-ligand system.

Reaction of Li/Cl phosphinidenoid pentacarbonyltungsten(0) complexes 2a,b (R = CH(SiMe3)2, Cp*) with bifunctional phosphite-substituted ketone 3 yielded tungsten complexes 4a,b having a novel mixed-valence polycyclic P,C-cage ligand with a P–P bond. DFT calculations provide insight into an unusual product formation pathway.