Synthesis, thermal analysis, and spectroscopic and structural characterizations of zinc(II) complexes with salicylaldehydes

In this study, three new zinc(II) complexes with 5-substituted salicylaldehyde ligands (X-saloH) (X = 5-chloro, 5-nitro and 5-methyl) with the general formula [Zn(X-salo)(2)(CH3OH)n], (n = 0 or 2) were synthesized. An octahedral geometry was found for both the complexes [Zn(5-NO2-salo)(2)(CH3OH)(2)] and [Zn(5-Cl-salo)(2)(CH3OH)(2)] by single-crystal X-ray diffraction analysis. These complexes were characterized also by spectroscopy (IR and H-1-NMR). Simultaneous TG/DTG-DTA techniques were used to analyze their thermal behavior under inert atmosphere, with particular attention to determine their thermal degradation pathways, which was found to be a multi-step decomposition accompanied by the release of the ligand molecules. Finally, the kinetic analysis of the decomposition processes was performed by applying both the isoconversional Ozawa-Flynn-Wall (OFW) and the Kissinger-Akahira-Sunose (KAS) methods.