New Type of Coordinatively Unsaturated Zirconium(IV) Complexes: (N,N,N'-Tris(trimethylsilyl)diamido -N''-(trimethylsilyl)-P-methylphosphonimidato)--trichlorozirconium(IV). Molecular Structure of the Product of Its Reaction with Tetrahydrofuran

The authors use phosphenodiimidic amides for the preparation of coordinatively unsaturated complexes of transition metals. The synthesis of a stable complex of 5-coordinate zirconium stabilized with a phosphonimidic diamide ligand is described; up to now compounds such as these have been known only for some cyclopentadienyl derivatives