Evaluation of newly synthesized derivatives of bis(hydrazine‐1‐carbothioamide) and their metal complexes synthesized in bulk and nano size as potent anticancer agents

A series of new metal complexes were synthesized in both bulk and nano size using green methods, starting with the reaction of (E)‐N′‐(E)‐2‐bromobenzylidene]‐4‐oxo‐4‐(piperidin‐1‐yl)but‐2‐enehydrazide with thiosemicarbazide and different metal halides such as CuI·2H₂O, CuCl₂·2H₂O, CoCl₂·2H₂O, and ZnCl₂·2H₂O, and metal nitrate such as Ga(NO₃)₃·2H₂O. Structures of these metal complexes were confirmed using different spectroscopic methods, elemental analysis, electronic spectra, and microanalytical methods (scanning electron microscopy and transmission electron microscopy) for nano complexes. The distorted octahedral geometry for all complexes was suggested based on magnetic moments and electronic spectral studies. The cytotoxic activity of the compounds was investigated against human hepatocellular carcinoma (HepG2) and human colorectal carcinoma (HCT‐116) cell lines. Most tested compounds had higher inhibitory activity than the standard vinblastine drug. Interestingly, the nano‐sized Ga(III) complex 11 was the most potent compound against the two tested cell lines, with 50% inhibitory concentration (IC₅₀) of 2.56 μg/mL for HepG2, compared with the reference drug vinblastine (IC₅₀ 15.6 μg/mL), and IC₅₀ 4.64 μg/mL for HCT‐116, compared with the standard (IC₅₀ 13.9 μg/mL). The bioassay results helped us identify new potent and selective anticancer agents.