Saccharin complexes of Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II) with ethanolamine and diethanolamine: synthesis, spectroscopic and thermal characteristics. Crystal structures of [Zn(ea)_2(sac)_2] and [Cu_2(#mu#-dea)_2(sac)_2]

摘要

New mixed ligand Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II) complexes of saccharin (sac) with ethanolamine (ea) and diethanolamine (dea) with synthesized and characterized by elemental analyses, magnetic moments, US-Vis and IR spectra. The Co(II)-ea, Co(II)-dea and Cu(II)-dea complexes are dimeric, while all the other complexes of ea and dea are mononuclear. The crystal structures of [Zn(ea)_2(sac)_2] and [Cu_2(#mu#-dea)_2(sac)_2] complexes were determined by single X-ray diffraction. In the Zn(II) complex, the Zn(II) ion sits on a center os symmetry and is octahedrally coordinated by two bidentate ea (N,O) and two monodentate sea (N) ligands. The centrosymmetric binuclear Cu(II) complex contains two strongly distorted square-planarly coordinated Cu(II) ions bridged by two alkoxo groups of the deprotonated dea. The dea ligand also coordinates to the Cu(II) ions through its nitrogen, while the other ethanolic group does not involve in coordination. The saccharinate anion coordinates to the Cu(II) ion with its nitrogen. Thermal behavior of the complexes was studied using DTA and TG in nitrogen atmosphere. Endothermic degradation of the ea and dea ligands occurs in the first stages os decomposition and the sac anions decompose at higher temperatures to give corresponding metal oxides or metals.