Sonication-assisted synthesis of some new mercury complexes with a tetradentate Schiff base ligand: Antimicrobial and thermal behaviors

Among different ligands used for synthesis of new coordination compounds in inorganic chemistry, Schiff base ligands are still on top because of their easy preparation, various properties and coordinating ability toward different metals ions [1]. Schiff base ligands based on the number of donor sites are classified to monodentate, bidentate, tridentate and so on. Their complexes have been extensively studied in the past few years for antibacterial and anticancer activities, catalysts, models of metalloenzymes and luminescent properties [2, 3]. In this work, a new N4-Schiff base ligand obtained from condensation of 2- nitrocinnamaldehyde and triethylenetetraamine has been successfully synthesized and its mercury complexes were characterized by FT-IR, 1H NMR, UV–Vis spectra and molar conductance measurements. Based on spectral data, the general formula of HgLX2 (X =Cl-, I-, N3 and SCN-) was proposed for the mercury complexes. The mercury compounds in nanostructure size were also prepared by sonochemical method. The nano-structure compounds were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Furthermore, the antimicrobial activity of the ligand and its mercury complexes against four gram positive and gram negative bacteria and also two fungi was assessed by the disk diffusion method. Also, DNA cleavage potential of all compounds was investigated by agarose gel electrophoresis method. Finally, thermal behaviors of all compounds were studied by TG/DTG/DTA analyses data