Reactivity of [Cp''2 Zr(η1:1 -E4 )] (E=P, As) towards Nucleophiles

Abstract

The functionalization of the polypnictogen ligand complexes [Cp''₂ Zr(η^1:1 -E₄ )] (E=P (1 a), As (1 b); Cp''=1,3-di-tertbutyl-cyclopentadienyl) is focused to modify the features of the polypnictogen unit to explore new synthetic pathways for further transformations. The reaction behavior of 1 towards main group nucleophiles is investigated. The reaction of 1 a with ^t BuLi leads to the ionic product Li[Cp''₂ Zr(η^1:1 -P₄ ^t Bu)] (2) where an organic group is attached to a bridgehead phosphorus atom of the butterfly unit. Further reactions of 2 with quenching electrophilic reagents enable the introduction of other substituents. Moreover, a condensation of 2 to [(Cp''₂ Zr)₂ (μ,η^1:1:1:1 -P₈ ^t Bu₂ )] (3), containing a novel P₈ -unit, has been observed. The reaction of 1 with LiNMe₂ and LiCH₂ SiMe₃ leads to a partial fragmentation of the E₄ unit and the compounds [Cp''₂ Zr(η² -E₃ Nu)] (Nu=NMe₂ : E=P (6 a), As (6 b); Nu=CH₂ SiMe₃ : E=P (7 a), As (7 b)) are formed.

Keywords: arsenic; nucleophile; phosphorus; polypnictogen complexes; triple decker complex.