Effect of Structure and Composition of Copper and Cobalt Complexes with Schiff Base Ligands on their DNA/Protein Interaction and Cytotoxicity

Four transition metal complexes, namely Cu 2 Cl 2 (HL 1 ) 2 ( 1 ), Co(HL 1 ) 2 ( 2 ), Cu(HL 2 ) 2 ( 3 ), Co(HL 2 ) 3 ( 4 ) {H 2 L 1 = 2‐{[2‐(2‐hydroxy‐ethoxy)‐ethylimino]‐methyl}‐phenol, H 2 L 2 = 3‐{[2‐(2‐hydroxy‐ethoxy)‐ethylimino]‐methyl}‐naphthalen‐2‐ol} were synthesized and characterized by single‐crystal X‐ray diffraction, IR spectroscopy, and elemental analysis. The interactions of these copper and cobalt complexes with calf thymus DNA (CT‐DNA) were studied by absorption and emission titration spectroscopic methods. The interactions of these copper and cobalt complexes with bovine serum albumin (BSA) were also investigated using fluorescence, UV/Vis, and synchronous fluorescence spectroscopy. Further, the in vitro cytotoxic effect of the complexes are examined on human colon carcinoma cell lines (HCT‐116) and human lung carcinoma cell line (A549).