Synthesis and characterization of thiosemicarbazone metal complexes: Crystal structure, and antiproliferation activity against breast (MCF7) and lung (A549) cancers

•Crystal structure of 2-(2,3-dihydroxybenzylidene)-N-ethylhydrazine-1-carbothioamide has been solved by x-ray crystallography and characterized by FTIR, CHNS, UV–vis, GC–MS, TGA, and NMR.•A distorted octahedral structure was proposed for the Ni(II) complex, square-pyramidal structure for Cu(II) complex, square-planar structure for both Pd(II) and Pt(II) complexes.•Potent antiproliferation activity against MCF7 and A549 cancer cells. Thiosemicarbazone compound has pronounced anticancer activity, which increases by metal ions presence. New Ni(II), Cu(II), Pd(II), and Pt(II) complexes synthesized from 2-(2,3-dihydroxy benzylidene)-N-ethylhydrazine-1-carbothioamide ligand H3L and had been characterized via NMR, GC–MS, FTIR, CHNS, UV–vis, TGA, magnetic susceptibility measurements, and molar electric conductivity. X‐ray crystallographic data and the refinement structure of thiosemicarbazide ligand indicated a clear light colorless block with the formula C10H13N3O2S, which belongs to a monoclinic system with P1 21/ c1 space group and adopts orthorhombic crystal with a = 5.1509(3) Å; b = 10.2856(6) Å; c = 11.3261(6) Å. The ligand and the metal complexes were also tested for antiproliferation activity against the MCF7 breast and A549 lung cancer cell lines. The data showed that Ni(II), Cu(II), Pd(II), and Pt(II) complexes had potent antiproliferation activity at the micromolar level. Pt(II) complex with square planar geometry exhibits the highest antiproliferation activity, while Ni(II) complex with distorted octahedral geometry showed the lowest antiproliferation activity in both cell lines. [Display omitted]