Low-dimensional compounds containing bioactive ligands. Part XI: Synthesis, structures, spectra, in vitro anti-tumor and antimicrobial activities of 3d metal complexes with 8-hydroxyquinoline-5-sulfonic acid

Abstract Five 3d metal [M(H2O)2(SQ)]n complexes, where M is Mn (1), Co (2), Ni (3), Zn (4) and Cu (5), and SQ is the dianion of 8-hydroxyquinoline-5-sulfonic acid have been prepared and characterized by IR spectroscopy and elemental analysis. X-ray structure analysis of 1 and 5 in combination with IR spectroscopy of all five complexes showed that complexes 1–4 are isostructural 2D polymers, while 5 is 1D polymer due to the different bonding character of SQ. Stability of all complexes in DMSO was proved by UV–Vis spectroscopy and for 4 also verified by 1H and 13C NMR spectroscopy. Cytotoxic activity tests against cervical carcinoma HeLa, colon carcinoma HCT116 and normal human fibroblast MRC-5 cell lines showed moderate but selective cytotoxicity of all complexes. Complex 1 exhibited highest activity with IC50 = 39.1 and 33.4 µM, respectively, but is lower than activity of cisplatin (CP) which IC50 = 24.3 and 14.3 µM, respectively. However, their cytotoxic activity against healthy MRC-5 cells (IC50 > 92 µM) is much lower than CP (IC50 = 19.7 µM). Antimicrobial activity of all complexes against 9 strains of pathogenic bacteria, five mould species and two yeast species is negligible.