Synthesis, structure and anticancer activity of copper(II) complexes of <i style="">N</i>-benzyl-2-(diethylamino)acetamide and 2-(diethylamino)-<i style="">N</i>-phenylethylacetamide

Abstract

The ligands <i>N</i>-benzyl-2-(diethylamino)acetamide, (HL¹) and 2-(diethylamino)-<i>N</i>-phenylethylacetamide (HL²), have been used to synthesize copper(II) complexes, [Cu(HL¹)₂](ClO₄)₂ <b>(1)</b> and [Cu(HL²)₂](ClO₄)₂ <b>(2)</b>, respectively. Both complexes are well characterized by various spectral and physical methods. The crystal structure of complex <b style="">(1)</b> reveals that two bidentate ligands coordinate the Cu(II) ion via O_amide and N_amine atoms in the basal plane whereas one of the ClO₄^- ions occupies the apical position maintaining a square–pyramidal geometry. Screening results for anti–proliferative studies against the U87 and HeLa cancerous cells indicate promising activity. The complexes enhanced growth inhibition and cell death in a concentration and time dependent manner for both U87 and HeLa cell lines. Of the two compounds, complex <b>(2)</b> exhibits better activity against both HeLa and U87 cells. Further, both complexes are specifically potent against U87 after 72 h of treatment. Micronucleus and apoptosis frequencies are 3 – 4 times higher in treated cells when compared with untreated control. Despite potent <i style="">in vitro</i> activity, both complexes exhibit diminished cytotoxicity against the normal human HEK cells at all effective concentrations.