Structure of the cobalt(II)-“capped” porphyrin, Co(C₃-Cap).3CHCl₃

The structure of Co(C₃-Cap).3CHCl₃ consists of the packing of discrete porphyrin and solvate molecules. The Co(C₃-Cap) moiety displays its expected connectivity in which the mean planes of the benzene cap and the porphyrin are nearly coplanar (dihedral angle, 2.4°) with the center of the cap nearly over the Co site. The Co atom is 3.436 Å from the mean cap plane; the centroid of the cap atoms is 3.494 Å from the mean porphyrin plane. Thus this C₃-cap displays a cap-to-porphyrin separation that is about 0.5 Å less than that found in the known C₂-cap structures. The porphyrin in Co(C₃-Cap) is severely ruffled with an average deviation of the atoms from the mean porphyrin plane of 0.30 Å and individual deviations as large as 0.6 Å. Implications of structural results on the C₂-caps and the present C₃-cap for O₂ and CO affinities are discussed. Crystallographic data: monoclinic, P2₁/n, Z = 4, a = 20.111 (13) Å, b = 15.660 (11) Å, c = 22.796 (16) Å, β = 110.49 (2)° at -150 °C, 8153 observations, 443 variables, R(F) (F_∘ ² > 3σ(F_∘ ²)) = 0.100. The solvate molecules are badly disordered.