Reactivity of [Cp'' 2 Zr(η 1:1 -E 4 )] (E=P, As) towards Nucleophiles.

The functionalization of the polypnictogen ligand complexes [Cp'' 2 Zr(η 1:1 -E 4 )] (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 -P 4 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 -P 8 t Bu 2 )] (3), containing a novel P 8 -unit, has been observed. The reaction of 1 with LiNMe 2 and LiCH 2 SiMe 3 leads to a partial fragmentation of the E 4 unit and the compounds [Cp'' 2 Zr(η 2 -E 3 Nu)] (Nu=NMe 2 : E=P (6 a), As (6 b); Nu=CH 2 SiMe 3 : E=P (7 a), As (7 b)) are formed.