Synthesis and coordination behavior of a zirconocene bis(borylphosphane)

The reaction of LiP(H)B(NiPr2)[N(SiMe3)2]·DME with Cp2ZrCl2 in a 2:1 ratio yields the metallodiphosphane Cp2Zr{P(H)B(NiPr2)[N(SiMe3)2]}2 (3a). Combination of 3a with Mo(CO)4 (norbornadiene) provides the adduct Cp2Zr{P(H)B(NiPr2)[N(SiMe3)2]}2·Mo(CO)4 (4a) in which the metallo-diphosphane 3a acts as a chelating ligand. The compounds have been characterized by spectroscopic methods and the molecular structures of 3a and 4a have been determined by single-crystal X-ray diffraction methods. The chemical and structural features are compared and contrasted with related metallo-diphosphanes that contain organic substituents on the diphosphane P atoms.