Synthesis, structure and biological properties of a series of dicopper(bis-thiosemicarbazone) complexes

Fifteen new coordination binuclear compounds of copper(ii) were synthesized based on substituted 4-tert-butyl-2,6-bis(N⁴-thiosemicarbazonyl)phenol (H₃L^1-3) ditopic ligands. The complexes were characterized using FT-IR spectroscopy, elemental analysis, MALDI-TOF analysis and X-ray diffraction studies highlighting the formation of dinuclear species with various bridging ligands between the two copper(ii) atoms and in some cases the dimerization of these species into tetranuclear complexes. The antioxidant, antimicrobial and antifungal activities of ligands and their copper(ii) coordination complexes have been investigated. In particular, the complexes show similar or better antimicrobial and antifungal properties than the drugs commonly used in this field. The structure-biological activity relationship is discussed based on the nature of the ligand and the copper salt used in the synthesis of the complexes.