Phosphoraneiminato complexes of zirconium and hafnium with clusterlike structures

Article abstract of DOI:10.1002/zaac.19976230137

The tetrachlorides of zirconium and hafnium react with excess phosphaneimine Me₃SiNPMe₃ at 220°C in the presence of sodium fluoride by cleaving FSiMe₃ to form the ionic complexes [Zr₃Cl₆(NPMe₃)₅]⁺[Zr ₂Cl₆(NPMe₃)₃]^- and [Hf₃Cl₆(NPMe₃)₅]⁺[Hf ₂Cl₇(NPMe₃)₂]^-. According to crystal structure analyses in the cations the three metal atoms together with three μ₂-NPMe₃^- groups and two NPMe₃^- groups with μ₃-function are forming trigonal bipyramids. In the anion of the zirconium complex the Zr atoms are linked by three μ₂-N bridges, whereas in the anion of the hafnium compound bridging is effected by two μ₂-N bridges and one μ₂-Cl bridge. Primary products in the reaction of MCl₄ (M = Zr, Hf) with silylated phosphaneimines are donor-acceptor complexes like [ZrCl₄(Me₃SiNPPh₃)] which has been characterized crystallographically as an example. In the molecular complex the Zr-atom is coordinated in a trigonal bipyramidal fashion.