Dual‐Function Schiff Base/Nitro‐Phenanthroline Cu(II), Co(II), and Mn(II) Complexes: Exploring Cytotoxic Activity, Catalytic Efficiency, and Molecular Docking Insights

Abstract

This study reports the synthesis and characterization of mixed‐ligand Cu(II), Co(II), and Mn(II) complexes derived from 2‐(((2‐hydroxyphenyl)imino)methyl)‐4‐methoxy‐6‐nitrophenol (L 1 ) and 5‐nitro‐1,10‐phenanthroline (L 2 ). The ligand and complexes were characterized by 1 H/ 13 C NMR (L 1 only), FT‐IR, UV–vis, LC‐MS/MS, TGA, and elemental analysis. Cytotoxicity studies against A549 and HTB‐54 lung cancer cells identified the Cu(II) complex as the most active compound, with IC 50 values of 24.05 and 22.08 µM, respectively, while showing lower toxicity toward BEAS‐2B normal cells (IC 50 = 39.08 µM). The Cu(II) complex significantly inhibited cell migration and induced apoptosis, supported by increased Bax expression in qPCR analysis. Molecular docking with selected cancer‐related protein targets further supported its proposed anticancer mechanism. The catalytic activity of the complexes was investigated for the solvent‐free cycloaddition of CO 2 with epoxides. The Co(II) complex exhibited the highest catalytic performance, affording 86.5% yield and 97.0% selectivity in the presence of DMAP under optimized conditions. Density functional theory (DFT) calculations provided the E HOMO , E LUMO , chemical potential, hardness, softness, electrophilicity index, and MEP profile of the ligand and complexes, demonstrating their multifunctional potential for anticancer and sustainable catalytic applications.