Synthesis and structure of dicopper(II) complexes bridged by N-(5-chloro-2-hydroxyphenyl)-N′-[3-(methy lamino)propyl]oxamide: Evaluation of DNA/protein binding, DNA cleavage, and in vitro anticancer activity

• Three new μ-oxamido-bridged dicopper(II) complexes were synthesized and structurally characterized.
• These complexes can intercalate HS-DNA, and bind to protein BSA by static quenching mechanism.
• The cytotoxicities of these complexes are consistent with their binding abilities following the order 1 > 2 > 3.
• The complex 1 exhibits the cleavage capacity for plasmid DNA through an oxidative process involving hydroxyl radical.
• The effects of terminal ligands on the structures and related properties were preliminarily studied.

Three new dicopper(II) complexes bridged by N-(5-chloro-2-hydroxyphenyl)-N′-[3-(methylamino)-propyl]oxamide (H3chmpoxd) and end-capped with 1,10-phenanthroline (phen); 2,2’-diamino-4,4′-bithiazole (dabt); and 2,2’-bipyridine (bpy), namely [Cu2(chmpoxd)(H2O)(phen)](ClO4)⋅CH3CN (1), [Cu2(chmpoxd)(dabt)(C2H5OH)](NO3) (2) and [Cu2(chmpoxd)(H2O)(bpy)](NO3)⋅CH3CN (3), were synthesized and structurally characterized. The single-crystal X-ray diffraction analysis revealed that both the copper(II) ions bridged by the cis-chmpoxd3− ligands in the three complexes are in square-planar and square-pyramidal environments, respectively. The reactivity towards herring sperm DNA (HS-DNA) and protein bovine serum albumin (BSA) indicated that these copper(II) complexes can interact with the DNA in the mode of intercalation, and bind to BSA responsible for quenching of tryptophan fluorescence by the static quenching mechanism. The cytotoxicity and DNA cleavage suggested that all the dicopper(II) complexes are active against the selected tumor cell lines, and the complex 1 exhibits the cleavage capacity for plasmid DNA.

Three new μ-oxamido-bridged dicopper(II) complexes were synthesized and structurally characterized. The DNA/protein binding properties, DNA cleavage and in vitro anticancer activities were investigated.Figure optionsDownload as PowerPoint slide