ABSOLUTE CONFIGURATION OF A DISSYMMETRIC PSEUDOTETRAHEDRAL COORDINATION COMPOUND CONTAINING A RESTRICTED BIPHENYL . MOLECULAR STRUCTURE OF DELTA-2,2'-BIS(SALICYLIDENAMINATO)-(+)D-(R)-6,6'-DIMETHYLBIPHENYLCOBALT (2)

The crystal and molecular structures of the dissymmetric molecule, Δ-2,2ʹ-bis(salicylidenaminato)-(+)n-(.R)-6,6ʹ-dimethylbiphenylcobalt(II), Δ-Co(sal)2-(R)-bmp, have been determined by single-crystal X-ray diffraction. The compound crystallizes in the orthorhombic space group P 212121 with a = 17.978, b = 11.206, and c = 11.628 Å. For Z = 4 the measured and calculated densities are 1.35 ± 0.02 and 1.353 g/cm3, respectively. Counter data were collected for 1745 independent reflections by the stationary-crystal-stationary-counter technique. The structure was solved using Patterson and Fourier methods and refined by least-squares techniques to a conventional R value of 0.098. The absolute configuration was determined from a comparison of 18 (hkl), (hkl) pairs and found to be R for the biphenyl moiety. The R configuration of the diamine uniquely establishes the A configuration for the complex as a whole as predicted by OʹConnor, Ernst, and Holm. The structure consists of discrete molecules wherein the ligand atoms surround the cobalt atom in a highly distorted tetrahedral fashion.^ The average bond distances involving the cobalt atom are Co-N = 2.09 ‡ 0.01 Å, and Co-O = 1.90 ± 0.01 Å. © 1969, American Chemical Society. All rights reserved.