Microwave-assisted synthesis and DNA-binding studies of half-sandwich ruthenium(II) arene complexes containing phenanthroimidazole-triarylamine hybrids

A new series of half-sandwich Ru(II)-arene complexes with phenanthroimidazole-triarylamine hybrid ligands were synthesized and scrutinized for DNA binding studies. The metal complexes were prepared via microwave-assisted synthesis with high yield and purity. The interaction of Ru(II)-arene complex with calf thymus DNA was studied by spectrophotometric methods. All six complexes exhibited significant interaction with CT-DNA. Methoxyphenyl-substituted metal complex showed the highest binding efficiency with a binding constant (K-b) of 5.053 x 10(4) M-1 due to its electron-rich nature. The methoxyphenyl group remarkably enhanced the interaction through stabilization of pi-orbital of the metal complex which resulted in the efficient coupling. Phenyl- and thiophene-substituted ligands also showed good binding constants of 4.908 x 10(4) M-1 and 4.509 x 10(4) M-1, respectively. The absorption and ethidium bromide displacement studies declare that both the intercalation and groove binding is anticipated by these complexes. These Ru(II) complexes with phenanthroimidazole-triarylamine hybrid ligands can be realized as efficient DNA binding agents.