Ca(II), Zn(II) and Au(III) Sulfamethoxazole Sulfa-drug Complexes: Synthesis, Spectroscopic and Anticancer Evaluation studies

Herein in this article, three new Ca(II), Zn(II) and Au(III) complexes of sulfamethoxazole (SZ) (sulfa-drug) have been synthesized for the first time. The sulfa-drugs have a great attentions because of their therapeutic applications against bacterial infections. The SZ complexes were discussed with the help of elemental analyses, molar conductance and spectroscopic instruments e.g. IR, 1H-NMR, and electronic spectra. Investigations of the infrared spectra of the SZ and their metal complexes indicated the vibrations due to the sulfonamido (SO2 and –NH) and isoxazole (C=N) groups are shifted with respect to the free molecule in line with their coordination to the metal. In case of calcium(II) and zinc(II) complexes, the coordination site of SZ are the sulfonyl oxygen and SO2-NH sulfonamide nitrogen, but in gold(III) complex, the gold metal ions coordinates through the sulfonyl oxygen and isoxazole nitrogen. These complexes are formulated as: [Ca(SZ)(Cl)2)].8H2O (1), [Zn(SZ)(Cl)2].2H2O (2) and [Au(SZ)(Cl)2].Cl (3). The molar conductance data reveals that both Ca(II) and Zn(II) complexes are non-electrolyte but gold(III) complex is electrolyte. The morphological nano structures of SZ complexes were checked using X-ray powder diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM). The gold(III) complex was recorded good anticancer behavior against Human colon carcinoma (HCT-116) cells and human hepatocellular carcinoma (HepG-2) cells.