Synthesis, Crystal Structure, and Spectrum Properties of Cobalt(II) Complexes Based on Tridentate 1,3-Bis(benzimidazol-2-yl)-2-oxopropane Ligand and Derivative

Two new cobalt(II) complexes [Co(obb)(2)](pic)(2)center dot 3(C(2)H(3)N) (1) and [Co(Etobb)(2)](pic)(2)center dot 2DMF (2) were prepared by the reaction of cobalt(II) picrate with the ligands 1,3-bis(benzimidazol-2-y1)-2-oxopropane (obb) and 1,3-bis(1-ethylbenzimidazol-2-y1)-2-oxopropane (Etobb), respectively. Single crystal X-ray diffraction revealed that [Co(obb)(2)](2+) and [Co(Etobb)(2)](2+) have a different arrangement. In complex 1 the coordination sphere around cobalt(11) is distorted tetrahedral, whereas in complex 2 the coordination sphere around cobalt(II) is distorted octahedral (where the N4 equatorial plane is formed by four benzimidazoles nitrogen atoms and the axial positions are occupied by two oxygen atoms from the two ligands). The complexes were also identified by IR and UV/Vis spectroscopy.