Anti-cancer and anti-fungal evaluation of novel palladium(II) 1-phenyl-1H-tetrazol-5-thiol complexes

The binuclear [Pd2(κ2-ptt)4] (1) and mixed ligand complexes of the type [Pd(κ1-S-ptt)2(κ2-diamine)] (2–4) (Hptt is 1-phenyl-1H-tetrazole-5-thiol), diamine; ethylene diamine (en), 1,10-phenanthroline (Phen) or 2,2′-bipyridyl (Bipy) as co-ligands have been synthesized. The obtained complexes were characterized by elemental analysis, 1H-, 13C-{1H} NMR, molar conductivity, UV–Vis and IR spectroscopy. In complex 1 the ptt anion coordinated as a bridging bidentate via the thione sulfur atom and deprotonated nitrogen atom of the heterocyclic ring to afford a dimeric complex. Whereas in 2–4 the ptt bonded as a monodentate through the thiolato sulfur atom, while the diamine ligands are coordinated as bidentate chelates to afford a square planner arrangement around the Pd(II) center. The anti-fungal activity of the prepared complexes (1–4) was tested against two fungi types (Candida albicans, and Aspergillus niger). All the complexes showed moderate activity compared to standard Fluconazole. Moreover, the anti-cancer activity of complexes (2–4) were examined against ovarian and breast cancer cells. Cell viability assays show that complexes (2–4) are promising anti-tumor in vitro.