[Ni(η3-CH2C(CH3)CH2)(SbPh3)3][BAr′4]: an extremely active cationic allyl nickel–stibine catalyst for the oligomerization of styrene

The pseudotetrahedral, formally 5-coordinate complex [Ni(η3-CH2C(CH3)CH2)(SbPh3)3][BAr′4] (Ar′ = 3,5-C6H3(CF3)2) as well as the 4-coordinate derivative [Ni(η3-CH2C(CH3)CH2)(AsPh3)2][BAr′4] act as extremely efficient catalysts for the oligomerization of styrene.