Synthesis, crystal structures and biological activities of 2-acetylpyridine N(4)-cyclohexylthiosemicarbazone and its manganese(II) and nickel(II) complexes

2-Acetylpyridine N(4)-cyclohexylthiosemicarbazone (HL) and its manganese(II) and nickel(II) complexes formulated as [Mn(L)2] (1) and [Ni(L)2] (2) have been synthesized and characterized by elemental analysis, infrared spectra, mass spectra, and single-crystal X-ray diffraction studies. In the two complexes, the coordination polyhedron approaches an octahedron, where the two ligands coordinate to the metal via the pyridine nitrogen atom and the nitrogen and sulfur donors of the thiosemicarbazide moiety. Biological studies, carried out in vitro against selected bacteria and K562 leukaemia cell line, respectively, have shown that the free ligand and its complexes exhibited distinct differences in the biological activities.

Graphical Abstract2-Acetylpyridine N(4)-cyclohexylthiosemicarbazone and its manganese(II) and nickel(II) complexes have been synthesized and fully characterized. Biological studies, carried out in vitro against selected bacteria and K562 leukaemia cell line, respectively, have shown that the free ligand and its complexes exhibited distinct differences in the biological activities.Figure optionsDownload as PowerPoint slideResearch Highlights
► In summary, 2-acetylpyridine N(4)-cyclohexylthiosemicarbazone and its manganese(II) and nickel(II) complexes were synthesized and fully characterized.
► Biological studies showed that the title three compounds all exhibited important antibacterial activities and the coupling of 2-acetylpyridine N(4)-cyclohexylthiosemicarbazone to Mn(II) and Ni(II), respectively, leads to remarkable enhancement of its antitumor activity.
► This confirms the conclusion that the complexation with metals has a synergetic effect on the biological activity of thiosemicarbazones.