A Structurally Characterized Cobalt(I) σ-Alkane Complex

A cobalt sigma-alkane complex, [Co(Cy2P(CH2)(4)PCy2)(norbornane)][BAr4F], was synthesized by a single-crystal to single-crystal solid/gas hydrogenation from a norbornadiene precursor, and its structure was determined by X-ray crystallography. Magnetic data show this complex to be a triplet. Periodic DFT and electronic structure analyses revealed weak C-H -> Co sigma-interactions, augmented by dispersive stabilization between the alkane ligand and the anion microenvironment. The calculations are most consistent with a eta(1):eta(1)-alkane binding mode.