STRUCTURE OF THE COBALT(II)-CAPPED PORPHYRIN, CO(C3-CAP).3CHCL3

The structure of Co(C3-Cap) .cntdot. 3CHCl3 consists of the packing of discrete porphyrin and solvate molecules. Co(C3-Cap) moiety displays its expected connectivity in which the mean planes of the benzene cap and the porphrin are nearly coplanar (dihedral angle, 2.4.degree.) with the center of the cap nearly over the Co site. The Co atom is 3.436 .ANG. from the mean cap plane; the centroid of the cap atoms is 3.494 .ANG. from the mean porphyrin plane. Thus this C3-cap displays a cap-to-porhyrin separation that is about 0.5 .ANG. less than that found in the known C2-cap structures. The prophyrin in Co(C3-Cap) is severely ruffled with an average deviation of the atoms from the mean porphyrin plane of 0.30 .ANG. and individual deviations as large as 0.6 .ANG.. Implications of structural results on the C2-caps and the present C3-cap for O2 and CO affinities are discussed. Crystallographics data: monoclinic, P21, Z = 4, a = 20.111 (13) .ANG., b = 15.660 (11) .ANG., c = 22.796 (16) .ANG., .beta. = 110.49 (2).degree. at - 150.degree. C, 8153 observations, 443 variables, R(F) (Fo2 > 3 .sigma. Fo2)) = 0.100. The solvate molecules are badly disordered.