Synthesis, characterization, DFT, cytotoxicity evaluation and molecular docking of a new carbothioamide ligand and its coordination compounds

•New carbothioamide ligand and its metal complexes have been synthesizes.•The isolated compounds have been characterized by spectral and analytical techniques.•The cytotoxicity activity of the compounds has been evaluated. 2-(2-hydroxybenzoyl)-N-phenylhydrazine-1-carbothioamide (H4L) and its Zn(II), Co(II), Cu(II), and Ni(II) coordination compounds have been synthesized. The results of IR, Mass spectra, UV–visible, 1H&13C-NMR, ESR, effective magnetic moments and elemental analyses suggested various structures of the synthesized coordination compounds. A square planar stereochemistry was suggested for Cu(II) and Ni(II) complexes, whereas octahedral stereochemistry was suggested for Co(II) complex. The structures were geometry optimized by DFT at exchange–correlation level (DFT/B3LYP) and 6-311++G(d,p) basis set. The electronic spectra were simulated and the optical band gap was calculated and compared with the experimental results. The determined optical band gap (Eg) represents direct electronic transitions with values in the range 4.42–4.45 eV. Molecular docking indicated the possible interactions of the compounds with the studied proteins. The cytotoxicity of the compounds were tested against HCT-116 and HePG2 cell lines and compared with Doxorubicin. H4L has a very strong cytotoxicity against the tested cell lines.