Synthesis and Characterization of Some New Binary and Ternary CuII Complexes

Abstract

New types of binary and ternary CuII complexes have been synthesized and characterized by elemental analyses, molar conductivities, spectral (I.R., U.V.-vis., E.S.R., mass), magnetic, and thermal analyses measurements. The binary CuII complexes are synthesized by the reaction of 2,2′-dipyridyl (dipy), thiosalicylic acid (tsa), 1,10-phenanthroline (phen), and/or tricine. {N-{tris-(hydroxymethyl) methyl} glycine}(tric) with CuCl2·2H2O in aqueous ethanol solution (50%). All the above compounds behave as neutral bidentate ligands coordinating via N, N; O, S; N, N and O, O, respectively. The results of thermal analyses, elemental analyses, as well as the weight loss methods suggest that the binary CuII complexes are dimeric in nature and contain at least four H2O molecules inside the coordination sphere. All the ternary CuII complexes were prepared by adding dl-serine (ser) to the abovementioned binary CuII complexes in which dl-serine behaves as a bidentate ligand and substitutes two water molecules from the coordination sphere of the binary complexes to complete the octahedral structure around the CuII ion together with the cleavage of the dimmer structure forming two monomers. The isolated solid complexes (binary and ternary) are blue in color, stable in air, and easily soluble in polar solvents (H2O, EtOH), indicating the electrolytic nature of these complexes, except the non-electrolyte bluish-grey CuII complex with the general formula, [Cu2(tsa)(ser)Cl4·(H2O)2]3H2O, which is insoluble in polar solvents. The geometries of the isolated solid CuII complexes are elucidated from the results of the molar conductivities, spectral (I.R., electronic, E.S.R., and mass), thermal (T.G.A., D.T.A.), and magnetic measurements. The room temperature solid state E.S.R. spectra of the binary complexes indicate the existence of dimeric structures around the CuII ions, while the ternary complexes show monomer form, except the bluish-grey complex. Also, the E.S.R. spectra of the Cu II complexes indicate that g g 2.0023, suggesting that the copper site has a d ground state.