Chemical modulation of the luminescence of a DNA-bound diruthenium(II) complex by copper(II) ion and EDTA

Abstract

A method for the chemical modulation of the photoluminescence of a DNA-bound diruthenium(II) complex, [(bipy) 2 Ru(bpib)Ru(bipy) 2 ] 4? (bipy = 2,2 0 -bipyridine, bpib = 1,4-bis([1, 10]phenanthroline [5,6-d]imidazol-2-yl) benzene) by the introduction of Cu 2? ion and EDTA has been developed. The diruthenium(II) complex showed strong photoluminescence both in buffer solutions and on an indium-tin oxide (ITO) surface, which was not modulated by Cu 2? or EDTA. The DNA-bound [(bipy) 2 Ru(bpib)Ru (bipy) 2 ] 4? with a binding constant of 3.8 9 10 4 M -1 showed an enhancement in the luminescence based on the electrostatic interaction between the complex and DNA. The presence of Cu 2? was found to quench the luminescence of DNA-bound [(bipy) 2 Ru(bpib)Ru(bipy) 2 ] 4? , but the quenched luminescence was recovered by addition of an equimolar concentration of EDTA. Hence, the photoluminescence of DNA-bound [(bipy) 2 Ru(bpib)Ru(bipy) 2 ] 4? depends strongly on the introduction of Cu 2? and EDTA.

In situ electrochemically tuned photoluminescence of [Ru(bpy)2(dppz)]2+ aggregates with single-walled carbon nanotubes and DNA monitored by guanine oxidation

“…The addition of DNA increases the luminescence of [Ru (bpy) 2 (dppz)] 2? due to intercalation between the DNA bases, involving a dp(Ru)?p * (dppz) electron transition (curve 2 and image 2) [19]. In general, SWCNTs used in aggregates can serve as a catalyst of redox reactions [20].…”

Recent advances in 1,10-phenanthroline ligands for chemosensing of cations and anions

“…On the contrary, addition of Cu 2+ ions to the 14a-ctDNA system caused only negligible changes in the luminescence or absorption spectrum, which pointed to the fact that the middle phen chelating unit of 14a was located deeply in between the hydrophobic DNA base pairs, making access of Cu 2+ ions difficult. 43 The complexes 14b, 14c, 16a and 16b also gave luminescence changes with Cu 2+ ions and ctDNA; [44][45][46][47] however, 15a-ctDNA and 15b-ctDNA were selective towards Co 2+ and Ag + , respectively. 48,49 The decreased emission intensity can be revived in both cases by adding EDTA (ethylenediamine tetraacetic acid) owing to a strong chelation of metal ions with EDTA.…”