Synthesis and structure of (η-cyclopentadienyl)(η-(1-(η-cyclopentadienyl)-2-phenyl-3-methyl-1-nickelaindenyl)nickel - the first analogue of nickelocene with a nickelacyclopentadienyl ring

A new metallacyclic compound (η⁵-cyclopentadienyl)(η⁵-(1-(η⁵-cyclopentadienyl)-2-phenyl-3-methyl-1-nickelaindenyl)nickel was synthesised and characterised. Its molecular and crystal structure was determined by X-ray measurements. It crystallises from hexane:THF mixture in the monoclinic crystal system and the P2₁/c space group. This is the first example of the homometallic metallametallocene of nickel. Like in nickelocene the central nickel atom has 20 valence electrons, so the compound can be regarded as the first nickelacyclic analogue of nickelocene.