Preparation and crystal and molecular structure of [1-chloro-2,2-bis(p-chlorophenyl)vinyl]bis(dimethylglyoximato)pyridinecobalt(III)

Crystals of the title compound, produced by reaction of bis(dimethylglyoximato)pyridinecobalt(I) with 1,1-bis(p-chlorophenyl)-2,2,2-trichloroethane (p,p′-DDT), are orthorhombic, space group Pn21a, a= 25.50(2), b= 23.13(2), c= 9.728(7)Å, Z= 8. The structure was solved by Patterson superposition methods from two-circle diffractometer data, and refined to R 0.048 for 3 545 unique observed reflections. The asymmetric unit consists of two molecules, each with octahedral co-ordination of cobalt, which differ significantly only in the relative orientations of the aromatic rings and the effect this has on the bis(dimethylglyoximato) plane. A chlorovinyl group is σ-bonded to cobalt, with mean bond lengths: Co–C 1.970(13), CC 1.366(15), and C–Cl 1.803(13)Å, mean Co–N distances are 2.042(10)(pyridine) and 1.877(10)Å(oxime). The symmetry of the crystallographically independent O–H ⋯ O hydrogen bonds [O ⋯ O (mean) 2.50(1)Å] is discussed. This σ-vinyl derivative may be relevant to the degradation of DDT in biological systems.