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.