Synthesis, Structure, and Biological Activity of Binuclear Mixed-Ligand Complexes of Nickel(II) Benzoylhydrazone 2-(N-Tosylamino)Benzaldehyde

Two new complexes of nickel(II) benzoylhydrazone 2-(N-tosylamino)benzaldehyde (H2L) with additional heterocyclic donor ligands L1 = 2,2′-bipyridine and L2 = 1,10-phenanthroline are synthesized. Structures and compositions of the obtained compounds are determined by elemental analysis, 1H NMR, and IR techniques. Crystal and molecular structures of the Ni(II) complexes are determined by single crystal X-ray diffraction. The adducts are shown to have dimeric structures: Ni2L2L1(CH3OH) and Ni2L2L2(CH3OH). In both adducts, one of nickel(II) ions is in a distorted square-planar environment while another is in the octahedral environment due to additional coordination of 2,2′-bipyridine or 1,10-phenanthroline and a methanol molecule. The biological activity of the complexes is studied. It is found that both adducts exhibit the protistocidal activity against Colpoda steinii, with Ni2L2L1(CH3OH) being twice less active and Ni2L2L2(CH3OH) being twice more active than the chloroquine reference.