Synthesis, Structure, and Reactivity of Group VI Metal Complexes Bearing Group IV Metallocenyldiphosphine Moieties and a Pentamethylcyclopentadienyl Ligand

A series of group VI metal complexes bearing a group IV metallocenyldiphosphine moiety and a pentamethylcyclopentadienyl ligand have been prepared and structurally characterized. Reactions of trinuclear complexes with KC8 give the corresponding neutral chloride-bridged complexes. Further reaction of the resulting chloride-bridged complex with NaBArF4 gives the corresponding monocationic chloride-bridged complex. On the other hand, reactions of the neutral chloride-bridged complexes with n-BuLi give the corresponding chloride-bridged alkyl complexes, where the group IV metallocene­(III) moiety and the coordinatively unsaturated group VI metal­(II) center are in close proximity. Spectroscopic and crystallographic studies of the reaction of a chloride-bridged alkyl complex with CO or a protic acid indicate that further disproportionation takes place at the alkyl zirconocene­(III) moiety.