Using methyl as substituted-radical in n-phen enhances the anticancer activities of [(DMF)Cu(n-phen)(NO3(-))2].

Abstract In order to seek better ligand for anticancer drug, we choose 1,10-phenanthroline (phen) and 2,9-dimethyl-1,10-phenanthroline (2,9-dmp) as predominant ligands, and synthetize two complexes:[(DMF)Cu(phen)(NO 3 ) 2 ] ( 1 ) and [(DMF)Cu(2,9-dmp)(NO 3 ) 2 ] ( 2 ) (DMF is dimethyl formamide). As for the five kinds of cancer cells, including A-549, Bel-7402, HCT-8, MDCK and L-1210 cells, our complexes showed higher inhibition ratio compared with anticancer drug 5-Fu (fluorouracil), ligand phenanthroline and Cu(NO 3 ) 2 . It's worth noting that complex 2's anticancer activity is much more efficient than that of complex 1 . This is because there are di-substituted-methyl in 2,9-dmp. By calculating, we found Δ complexes phenanthroline which showed that the energy gap between π ⁎ and π of the phenanthroline is decreased through coordination with Cu II . Computational ΔG 2 N) 1 N) 2 revealed that the coordinated 2,9-dmp is easier to dissociate with Cu II than phen, which is confirmed by the absorption peak at 460 nm in UV–visible (UV–vis) spectra of complex 2 . In summary, the phenanthroline is activated by Cu II -coordination, which is beneficial for anticancer. More importantly, the substituted-methyl radicals stimulated the phenanthroline and enhanced the anticancer properties more efficiently.