Syntheses and structures of the first terminal phosphanylphosphido complex of hafnium [Cp2Hf(Cl){η1-(Me3Si)P–P(NEt2)2}] and the first zirconocene-phosphanylphosphinidene dimer [Cp2Zr{μ2-P–P(NEt2)2}2ZrCp2]

Abstract

Reactions of (Et₂N)₂P–P(SiMe₃)Li with [Cp₂MCl₂] (M = Zr, Hf) in toluene or pentane yield the related terminal phosphanylphosphido complexes [Cp₂M(Cl){η¹-(Me₃Si)P–P(NEt₂)₂}]. The solid state structure of [Cp₂Hf(Cl){η¹-(Me₃Si)P–P(NEt₂)₂}] was established by single crystal X-ray diffraction. The reaction of (Et₂N)₂P–P(SiMe₃)Li with [Cp₂ZrCl₂] in THF or DME solutions leads to the formation of deep red crystals of the first neutral diamagnetic zirconocene-phosphanylphosphinidene dimer [Cp₂Zr{μ₂-P–P(NEt₂)₂}₂ZrCp₂]. The molecular structure of this compound was confirmed by X-ray diffraction. The reactions of (R₂N)₂P–P(SiMe₃)Li with [CpZrCl₃] yield the related tetraphosphetanes R₂NP(μ₂-PSiMe₃)₂PNR₂, which apparently are formed as a result of a transfer of NR₂ groups from a P atom to the Zr atom.