Dual Anticancer and Antimicrobial Activity of Novel Salicylal Carbothioamide Metal Complexes: Synthesis, Spectroscopic Characterization, and Molecular Docking Insights

Abstract A novel salicylal carbothioamide ligand was synthesized and used to prepare a series of transition metal complexes with Co(II), Ni(II), Cu(II), Mn(II), and Zn(II) in 1:1 and 1:2 metal-to-ligand stoichiometries. The synthesized complexes were fully characterized by elemental analysis, FT-IR, UV-Vis, molar conductivity, magnetic susceptibility, and thermogravimetric analysis (TGA). Selected compounds were further analyzed via ¹H NMR, and their proposed coordination modes were supported by spectroscopic shifts and thermal stability profiles.The biological activity of the compounds was evaluated via antimicrobial and cytotoxicity assays. Complexes AR4 and AK3 exhibited potent cytotoxicity against MCF-7 breast cancer cells, with IC₅₀ values of 55.26 µM and 62.17 µM, respectively, showing enhanced activity compared to the free ligand (147.63 µM). Antibacterial assays revealed moderate to good inhibition against Gram-positive and Gram-negative strains. Molecular docking studies were performed against the cancer-associated protein TRPM7 (PDB ID: 8W2L), revealing favorable binding energies and interactions that support the observed in vitro activity.The integration of spectroscopic characterization, thermal analysis, docking, and biological screening supports the potential of these carbothioamide-based metal complexes as promising anticancer and antimicrobial agents.