Syntheses and structures of mononuclear and binuclear transition metal complexes (Cu, Zn, Ni) with (salicylideneglycine and imidazole)

Four transition metal (Cu(II), Zn(II) and Ni(II)) complexes with a Schiff-base ligand (salicylideneglycine) have been synthesized. All complexes have been characterized by elemental analysis, IR spectra and UV-vis spectroscopy. Single-crystal analyses were performed with (C9H7NO3)Cu(C3H4N2) (1), (C9H7NO3)Zn(C3H4N2)2 (2), (C9H7NO3)2Ni2(C3H4N2)4 (3) and (C9H7NO3)Ni(C3H4N2)2(C4H5N2O) · CH3OH · 0.5H2O (4) and fluorescence spectra and thermogravimetric analyses were also carried out. Structural analyses show that 1, 2 and 4 have similar coordinated modes with the tridentate amino-Schiff-base ligand, but differ from the binuclear nickel complex 3. The tridentate amino-Schiff-base ligand contains aliphatic nitrogen, phenoxy, and carboxylic oxygen as three donor atoms. In addition, inter- and intra-molecular hydrogen bonds are also discussed.