Solution and solid behavior of mono and binuclear zinc() and nickel() complexes with dithiocarbazates: X-ray analysis, mass spectrometry and cytotoxicity against cancer cell lines

The current work reports the synthesis and investigation by physical-chemistry and spectroscopic methods of three dithiocarbazates (2-acetylpyridine- S -allyl-dithiocarbazate - HL 1 ; 2-acetylpyridine- S-p -bromobenzyl-dithiocarbazate - HL 2 ; and 2-acetylpyridine- S-p -nitrobenzyl-dithiocarbazate - HL 3 ) and six novel metal complexes derived from these Schiff-bases. Four crystal structures of the complexes are reported. The single crystal X-ray study showed two binuclear zinc( ii ) complexes with symmetrical and asymmetrical acetate bridges resulting in different coordination spheres. Another zinc( ii ) complex and three nickel( ii ) complexes present dithiocarbazates tridentate with NNS -donor atoms and octahedral geometry to the metal centers. The mass spectrometry data indicated the presence of the molecular ions [M + H] + and characteristic fragments of the compounds. All characterization indicated the same behavior of the compounds as a solid and in solution. The biological activity of the zinc( ii ) and nickel( ii ) salts, the free dithiocarbazate ligands and their metal complexes was evaluated by assays with carcinoma mammary MDA-MB-231 cells. The results revealed that the free dithiocarbazates present great in vitro antitumor activity, which is increased after the complexation with zinc, with emphasis on the dimeric complex (1) , which had an IC 50 of 2.0 μM and exhibits more potential inhibition of tumor cell growth than the nickel( ii ) complexes. We report the synthesis and characterization of metal complexes with dithiocarbazates and the cytotoxicity against the breast cancer line MDA-MB-231.