Crystal and molecular structure of tetra-μ-benzoato-bisquinolinedi-cobalt(II), a binuclear cobalt(II) carboxylate

The structure of the title compound has been determined by three-dimensional X-ray crystal structure analysis. The crystals are orthorhombic with unit cell dimensions a = 17.150(10), b = 19.703(11), c = 11.655(7) Å, Z = 4, space group Pcab. Full-matrix least-squares refinement using 1 221 reflections reached R = 0.061. The centrosymmetric molecule comprises two cobalt ions bridged by four benzoate anions with the two oxygen atoms of each benzoate group bonded to different cobalt ions. Square-pyramidal five-co-ordination of cobalt is completed by a quinoline molecule, but steric effects cause significant deviations from regularity with N-Co-O angles from 92 to 104°, Co-O distances from 2.017 to 2.072 Å, Co-O-C angles from 119.1 to 130.3°, and an included Co-Co-N angle of 168.3°. The Co-Co separation is 2.832 Å.