Synthesis, crystal structure, biomolecular interactions and anticancer properties of Ni(II), Cu(II) and Zn(II) complexes bearing S-allyldithiocarbazate

Bidentate Schiff – base ligand [H-emk-sadtc] and its Ni(II), Cu(II) and Zn(II) complexes were synthesized. Single crystal XRD studies revealed that all the complexes have distorted square planar geometry. DNA and BSA binding studies were displayed. Complexes were exhibit excellent catecholase and phosphatase hydrolysis activity. Cytotoxicity in the low μM range was found for all complexes. [Display omitted] •Dithiocarbazate Schiff base complexes have been synthesized.•They have been characterized by experimental and computational techniques.•CT-DNA and BSA binding affinity were studied.•Catecholase and phosphatase activity were studied.•In vitro cytotoxicity evaluation of the complexes. A new series of bivalent Ni(II), Cu(II) and Zn(II) metal complexes containing Schiff base ligand [H-emk-sadtc] [(E)-allyl 2-(butan-2-ylidene) hydrazine carbodithioate)] were synthesized and characterized by different spectroscopic techniques. The molecular structure of the ligand and its complexes 1 [(E)-allyl 2-(butan-2-ylidene) hydrazine carbodithioato nickel(II)], complex 2 [(E)-allyl 2-(butan-2-ylidene) hydrazine carbodithioato copper(II)], complex 3 [(E)-allyl 2-(butan-2-ylidene) hydrazine carbodithioato zinc(II)] were confirmed by single crystal X-ray crystallography. XRD data of the complexes had revealed a distorted square planar geometry around the metal ion, satisfied by N2S2 fashion. Density functional calculations of all the compounds in gas phase were performed by using DFT (B3LYP) with 6-311G basis set. The calculated FT-IR and structural data are in good agreement with the experimental results and confirmed by the experimental one. The interactions of calf thymus (CT) DNA and bovine serum albumin (BSA) with complexes 1–3 were explored by emission spectra. Catecholase and phosphatase-like activities of all the complexes were also investigated. An in vitro cytotoxicity study of the complexes had shown significant activity against human cervical cancer cell line (HeLa) with the best results of complex 2, which was found to be more toxic to cancer cells with a few micromolar concentrations, as the IC50 value, but significantly less toxic to normal cell lines. Additionally, the cell death analysis was carried out by AO/EB and DAPI staining methods.