SYNTHESIS AND STRUCTURE OF {M-OXALATO-BIS[ETHYLENEDIAMINETETRAACETATO- BISMUTHATO(III)]}PENTAAMMINETHIOCYANATOCOBALT(III) DODECAHYDRATE, [CO(NH3)5NCS]2[(EDTA)BI(M-C2O4)BI(EDTA)] • 12H2O

Abstract

A heterometallic complex of cobalt(III) and bismuth(III), [Co(NH3)5NCS]2[(Edta)Bi(μ-C2O4)Bi(Edta)] · 12H2O, was synthesized and studied by X-ray diffraction analysis. The crystals are monoclinic, a = 12.792(3) Å, b = 9.792(2) Å, c = 22.945(5) Å, β = 92.92(3)°, P(calcd) = 1.970 g/cm3, space group P21/c, Z = 4. The complex has an isle structure composed of [(Edta)Bi(μ-C2O4)Bi(Edta)]4- and [Co(NH3)5NCS]2+ complex ions and molecules of crystallization water. The Edta4- ligand functions as a hexadentate chelating (2N + 40) agent, while the oxalate ion acts as a bridging ligand. The thiocyanate ion is coordinated to cobalt(III) through the N atom, while the cation interacts with the anion via the Bi-S contact (3.571 Å). Hence, the coordination polyhedron of Bi can be regarded as a tricapped trigonal prism. It was shown that thermolysis of the complex proceeds in several stages, viz., the deaquation, deamination, and pyrolysis of its ligands.