Cobalt(II) and Nickel(II) Complexes with Nitrogen, Sulfur, and Selenium Containing Heterocyclic Ligands

Cobalt(II) and nickel(II) halide complexes with thiomorpholin-3-thione and thiazolidine-2-selenone have been prepared. Infrared and far infrared spectra, electronic spectral studies, and magnetic susceptibility measurements indicate that the cobalt derivatives are tetrahedral in structure, nickel chloro- and bromo-thiomorpholin-3-thione derivatives are octahedral while [Nits2I2] and all nickel thiazolidine-2-selenone complexes have a pseudo-tetrahedral symmetry. The probable site of bonding in the ligands is nitrogen in all the complexes studied here, except the nickel derivatives of thiazolidine-2-selenone. These results are confirmed by n.m.r. measurements. Spectroscopic parameters for the complexes have been calculated and compared against similar chromophores containing MN2X2 and MS2X2 chromophores.