Synthesis, characterization, theoretical study, and anticancer application of a new asymmetric ligand, N‐trans‐cinnamylidene‐1,2‐phenylenediamine, and its complexes

Abstract

In this work, a new asymmetric ligand, N‐trans‐cinnamylidene‐1,2‐phenylenediamine via the condensation reaction of 1,2‐phenylenediamine and trans‐cinnamaldehyde, and its complexes have been successfully synthesized. The ligand and its complexes were characterized by spectroscopic techniques including FT‐IR, 1H NMR, 13C NMR, ESI‐mass, UV‐vis, and physicochemical methods, such as molar conductivity, elemental analysis, and melting point. Based on the identification results, the general formula of MLX2 (X = Cl−, Br−, and M = Zn2+, Hg2+, Cd2+) was proposed for the complexes. Differential scanning calorimetric analysis was also used to investigate the thermal properties of the as‐synthesized compounds. Further, theoretical studies were performed on the ligand and its complexes. Molecular electrostatic potential surface analysis was done to distinguish the electrophilic and nucleophilic sites of the products. Nonlinear optical properties of the ligand and complexes were calculated and then compared with the standard nonlinear optical material. The frontier molecular orbitals were theoretically determined and the energy gap, global electrophilicity index, electronic chemical potential, ionization potential, absolute electronegativity, electron affinity, absolute hardness, and softness were calculated. Finally, thermodynamic properties of the compounds were evaluated. Moreover, the assessment of cytotoxicity effects of all compounds against HCT116 cancer cells was performed by the MTT assay. In vitro studies showed that HgLCl2 could considerably reduce cell viability and increase induction apoptosis and cell cycle arrest.