The crystal and molecular structure of μ-peroxo-bis-[3,3'-diimino-di-n-propylamine-bis(salicylaldehyde)cobalt(III)].C6H5CH3

Abstract

The structure of g-peroxo-bis-[3,3'-dii mino-di-n-propylamine-bis-salicylaldehyde cobalt(! II)] C6H 5CH 3, (CoOzN3CzoHE3)EOz.C6HsCH3, has been determined by single-crystal X-ray analysis. The red-black salt crystallizes in the monoclinic space group C2/c with unit-cell dimensions a= 10.236 (6), b=24.31 (2), c= 18.02 (1) ~, and /~= 104-06 (6)°; Z=4. The measured density of 1.37 (3) g.cm-3 agrees well with the value of 1.39 (1) g.cm-3 calculated for four formula units in the cell. Three-dimensional intensity data were collected on a Datex-automated General Electric diffractometer using Co Ke radiation. The structure was determined by Patterson and Fourier methods and refined by Fourier and leastsquares techniques to an R index of 0.12 for 1185 reflextions. Oxygen atoms of the salicylaldehyde groups are arranged in cis positions in the octahedra around the cobalt atoms while the imine nitrogen atoms are trans. The molecule crystallizes around a twofold axis with a skew, nonplanar Co-O-O-Co bridge arrangement. The O-O distance of 1.45 (2) ~ and the torsion angle around this bond of 149 ° indicate that the Oz group is best formulated as a peroxide (O~-) ion. A similar molecule can be crystallized from acetonitrile or acetone. Crystals obtained from these solvents are also monoclinic, space group P2/c, with approximate cell dimensions a= 10.35 (1), b= 11.39 (1), and c= 17.23 (1) /~; fl= 101.5(1) °. Partial data from a poorly formed crystal indicate a similar Co-O-O-Co arrangement about a twofold axis.