Diphenic acid/nicotinamide and 1,10-phenanthroline complexes of CoII, CuII and ZnII. Synthesis and structural investigation

Abstract

The complexes of diphenic acid with CoII and CuII metals and diphenic acid/nicotinamide mixed ligand with CoII and ZnII metals were synthesized and characterized of structural properties by elemental analysis, FT-IR spectra, thermo analytic TG-DTG/DTA and crystal X-ray diffraction methods. The pure ligand complexes of diphenic acid (C14H16O8Co (1), C14H16O8Cu (2)) and mixed ligand complexes of diphenic acid/nicotinamide (C40H38N4O14Co (3), C40H38N4O14Zn (4)) are similar to each other and they have P21, P21/n and space groups. The diphenic acid ligands in 1 and 2 complexes were coordinated to metal cations as dianionic bridge and in the others complexes (3 and 4) it was involved as monoanionic counter ion. The complexes of 1 and 2 are linked into sheets by a combination of O–H⋯O hydrogen bonds and the others complexes of 3 and 4 are linked into sheets by a combination of O–H⋯O, N–H⋯O and C–H⋯O hydrogen bonds. All of the complexes structures have distorted octahedral geometry. According to TG/DTG-DTA analysis, thermal decomposition of complexes starts with dehydration of coordinated aqua ligands. After the dehydration, neutral nicotinamide ligands start to decompose in mixed ligand complexes. Lastly, anionic diphenic acid ligands decompose and corresponding metal oxides remain as residual products of thermal degradation in reaction vessel.