Synthesis, crystal structures and antimicrobial activity of dimeric copper(II) complexes with 2-hydroxyphenyl-ethylidene-dithiocarbazates

The current work reports the synthesis and crystals structure of two copper(II) complexes [(CuL1)(2)] (1) and [(CuL2)(2)] (2), with S-allyl-2-(2 hydroxyphenyl ethylidene)dithiocarbazato and S benzyl 2 (2 hydroxyphenyl-ethylidene) dithiocarbazato (H2L1 and H2L2, respectively). The single-crystal X-ray analyses reveal dimeric structures of the complexes with a distorted square planar coordination geometry. The phenoxo bridging mode observed in these complexes is located between the two copper atoms with ONS-donor ligands. The crystal packings are stabilized by hydrogen bonds involving the adjacent molecules. The compounds were also characterized by physicochemical and spectroscopic methods. The antibacterial and antifungal properties of the free dithiocarbazates and its Cu(II) complexes have been evaluated against several multiresistant bacteria and fungi. In all experiments, a superior antimicrobial activity of the complexes was observed compared to the free ligands.