New insights into the reaction of nickelocene with methyllithium: the isolation and crystal structure of (NiCp)3(μ3-CH)

Thermolysis of the cyclopentadienylnickelmethyl complex [NiCp(CH3)(η2CH2double bond; length as m-dashCHC4H9)] in various solvents was studied. Separation of products by means of column chromatography allowed to isolate and crystallographically characterise (μ3-methylidyne)tris(cyclopentadienylnickel) cluster (NiCp)3(μ3-CH) (1). Cluster 1 crystallised from a hexane/THF mixture in hexagonal crystal system and P63 space group. Ni–Ni and Ni–C(methylidyne) distances were 2.3558(10) and 1.823(4) Å, respectively. Detailed studies showed that cluster (NiCp)3(μ3-CH) (1) was produced during the chromatography on alumina. The plausible precursor to 1 is described as (NiCp)6C.