Synthesis, Characterization, and Biological Activity of the Schiff Base and Its Ni(II), Cu(II), and Zn(II) Complexes Derived from 4-(Dimethylamino)benzaldehyde and S-Benzyldithiocarbazate

A Schiff base containing the nitrogen-sulfur donor chain [(CH 3 ) 2 N-C 6 H 4 -CH=N-NH-C(S)-SCH2C6H5] was prepared by the condensation of 4-(dimethylamino)benzaldehyde and S -benzyldithiocarbazate and coordinated with Ni(II), Cu(II), and Zn(II). The Schiff base and its metal complexes were characterized by elemental analysis, IR, 1 H and 13 C NMR, electronic absorption spectroscopy and some of their physicochemical properties were determined. The Schiff bases behaved as a bidentate uninegative ligand in all the complexes, giving square-planar geometrical structures with Ni(II) and Cu(II) and a tetrahedral structure with Zn(II). The Schiff base and its complexes were screened for antibacterial activity. The biological activity testing results showed that the complexes were more potent antibiotics than the free ligand. The Cu(II) and Ni(II) complexes displayed high antibacterial potency and Zn(II) was moderately active against bacteria.