Novel binuclear copper(II) complexes with sulfanylpyrazole ligands: Synthesis, crystal structure, fungicidal, cytostatic and cytotoxic activity

Abstract New binuclear copper(II) [Cu(II)] tetraligand complexes (six examples) with sulfanylpyrazole ligands were synthesized. Electron spin resonance (ESR) studies have shown that in solution the complexes are transformed to the mononuclear one. Fungicidal properties against Candida albicans were found for the Cu complexes with benzyl and phenyl substituents. An in vitro evaluation of the cytotoxic properties of Cu chelates against HEK293, Jurkat, MCF-7, and THP-1 cells identified the Cu complex with the cyclohexylsulfanyl substituent in the pyrazole core as the lead compound, whereas the Cu complex without a sulfur atom in the pyrazole ligand had virtually no cytotoxic or fungicidal activity. The lead Cu(II) complex was more active than cisplatin. Effect of the S-containing Cu complex on apoptosis and cell cycle distribution has been investigated as well.