Crystal structure of [(1,2,3,4,11,12-η)-anthracene]tris(trimethylstannyl)cobalt(III)

The asymmetric unit of the title structure, [Co(η⁶-C₁₄H₁₀){Sn(CH₃)₃}₃], contains two independent molecules. Each anthracene ligand is η⁶-coordinating to a Co^III cation and is nearly planar [fold angles of 5.4 (3) and 9.7 (3)°], as would be expected for its behaving almost entirely as a donor to a high-oxidation-state metal center. The slight fold in each anthracene ligand gives rise to slightly longer Co - C bond lengths to the ring junction carbon atoms than to the other four. Each Co^III cation is further coordinated by three Sn(CH₃)₃ ligands, giving each molecule a three-legged piano-stool geometry. In each of the two independent molecules, the trio of SnMe₃ ligands are modeled as disordered over two positions, rotated by approximately 30%, such that the C atoms nearly overlap. In one molecule, the disorder ratio refined to 0.9365 (8):0.0635 (8), while that for the other refined to 0.9686 (8):0.0314 (8). The molecules are well separated, and thus no significant intermolecular interactions are observed. The compound is of interest as the first structure report of an η⁶-anthracene cobalt(III) complex.