Synthesis, characterization, anticancer and antibacterial evaluation of Schiff base ligands derived from hydrazone and their transition metal complexes

In this paper, metal chelates of Schiff base derived from hydrazones have been prepared and characterized by 1HNMR, IR, UV–Vis spectroscopy and cyclic voltammetry. Single crystal X-ray crystallography studies confirm the structure of newly synthesized Schiff bases. The Schiff bases act as tridentate ligands. The free ligands and metal compounds are screened for their antibacterial activities against Gram-positive and Gram-negative bacteria. Further the cytotoxic effect of the ligands and their metal compounds examined on cancer cell lines showed that the metal compounds exhibit better activity than ligands. [Display omitted] •Three new metal complexes of hydrazone Schiff bases were synthesized and characterized.•Structures for the complexes were determined by X-ray diffraction.•The cyclic voltammetry behavior of these compounds was discussed.•Complexes showed good antibacterial and anticancer activity. Copper(II), Nickel(II) and Cobalt(III) complexes with Schiff base ligands derived from hydrazone, (HL1 = (E)-N′-(pyridin-2-ylmethylene)benzohydrazide, H2L2 = (E)-2-(2-hydroxybenzylidene)hydrazine-1-carboxamide and HL3 = (E)-2-(pyridin-2-ylmethylene)hydrazine-1-carboxamide, were synthesized and spectroscopically characterized by FT-IR, 1H NMR, UV–Vis spectroscopy, X-ray crystallography and cyclic voltammetry. The synthesized compounds have been screened for their antibacterial activities against the bacterial species E. coli, K. pneumonia (Gram-negative) and S. aureus, B. subtilis (Gram-positive) by minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) methods. In vitro anticancer studies of the ligands and coordination compounds (1–3) using MTT assay was also done. Results show that the complexes (1–3) have higher antibacterial and anticancer activities than the respective free ligands.