The crystal structure and single crystal polarized spectra of trans-bis(trichloroacetato)bis(N,N-dimethylethylenediamine)cobalt(II)

CO[(CH 3 ) 2 NCH 2 CH 2 NH 2 ] 2 [CCl 3 CO 2 ] 2 belongs to the monoclinic crystal system, space group P2 1 /c with a = 7.216(1) Å, b = 12.117(3) Å, c = 13.616(4) Å, β = 103.27(2)°, V = 1158.7 Å 3 , Z = 2. The structure was solved by the heavy atom method and was refined to R = 0.048, R w = 0.056 for 1761 reflections with I ≥ 3σ(I). The complexes lie on crystallographic centers of symmetry. Deviations from regular octahedral coordination are due to steric crowding and chelate ring constraints. The CoNMe 2 bond is longer than the CoNH 2 bond (2.258(3) vs. 2.100(3) Å). The CoO distance is 2.138(3) Å. The chelate rings each contain a disordered carbon atom such that these rings are 54% gauche and 46% envelope. There are intramolecular and intermolecular H-bonds between the Me 2 en and trichloracetate ligands. The polarized single crystal spectra are interpreted in terms of D 2h symmetry for the complex.