Axially chiral racemic half-sandwich nickel(ii) complexes by ring-closing metathesis

Abstract

A remarkable nickelacycle has been synthesised via olefin metathesis of the α,ω-diene complex [Ni(η⁵-C₅H₄R)(Br)(NHC)] (R = C(CH₃)₂CH₂CHCH₂, NHC = 1-(6-hexenyl)-3-(2,4,6-trimethylphenyl)-imidazol-2-ylidene). Single-crystal X-ray analysis reveals a helical shape of the molecule and stretching of some interatomic distances in the Ni(II) coordination sphere. The Cp-NHC tethered complex shows catalytic activity resembling that of the parent complexes.