Crystal and molecular structure of [NN′-ethylenebis(salicylideneiminato)]pyridine(vinyl)cobalt(III). Evidence of trans- and cis-influence in octahedral complexes

Abstract

The crystal structure of the title compound has been determined from three-dimensional X-ray data by conventional Fourier methods. The crystals are orthorhombic, space group pnma, with Z= 4, and cell dimensions a= 15·902(5), b= 17·871(10), c= 6·746(4)Å. After an anisotropic block-diagonal least-squares refinement R was 0·070 for 917 reflections. The cobalt atom has a distorted octahedral co-ordination polyhedron. The ‘salen’ ligand occupies the four equatorial positions whereas the vinyl group and the pyridine molecule occupy the two axial positions [Co–C 1·93(2) and Co–N 2·12(1)Å]. The complex has an umbrella-shape conformation with apparent m symmetry because of the statistical disorder of the vinyl group and ethylene bridge in the mirror plane. Comparison of the cobalt–axial-ligand bond lengths with those of analogous compounds provides further evidence of trans- and cis-influence in such octahedral complexes.