Cu(II) and Ni(II) Complexes of Anthracene‐Affixed Schiff Base: A Conflict between Covalent and Stacking Interactions with DNA Bases

Abstract

Abstract Four new mononuclear complexes [Cu(L1)Cl 2 ] ( 1 ), [Ni(L1)Cl 2 ] ( 2 ), [Cu(L2)Cl 2 ] ( 3 ) and [Ni(L2)Cl 2 ] ( 4 ), where L1 (1‐(anthracen‐9‐yl)‐N‐(1H‐benzo[d]imidazole‐2‐yl)methanimine) and L2 (1‐(anthracen‐9‐yl)‐N‐(benzo[d]thiazol‐2yl)methanimine) have been synthesized and characterized by various spectral and electro analytical techniques. The molecular structure of the ligands L1 and L2 were determined by the single crystal XRD method. The absorption and emission spectral approaches revealed that these complexes may partially be stacking in between the DNA bases. In contrast, the possibility of their covalent interaction was evaluated through the cyclic voltammetric techniques. All these obtained results revealed that the complexes 1‐4 could interact with HS‐DNA via covalent/partial intercalation modes and the quenching mechanism of BSA by all these complexes are through static mode. In addition, the in vitro cytotoxicity of the complexes on human gastric cancer cell lines have been observed by MTT and the fluorescence‐based morphological assessment obtained using Hoechst 33342 staining reveals that these complexes induces apoptosis against AGS cancer cells, among them best result was obtained for complex 3 (8.9 μM).