Photoluminescence quenching of [Ru(bpy)2(atatp)]2 + bound to a condensed DNA matrix

Abstract

A novel [Ru(bpy)2(atatp)]2+ (bpy=2,2′-bipyridine and atatp=acenaphtheno[1,2-b]-1,4,8,9-tetraazatriphenylene) can induce the condensation of herring sperm DNA to form an orange-red cast film via intercalation and electrostatic attraction. The thus-prepared cast film shows microsecond emission lifetimes and reversible luminescence tuning characteristics by oxygen and nitrogen with an on–off emission intensity ratio of 4.3. The photoluminescence of [Ru(bpy)2(atatp)]2+ bound to a DNA condensed matrix can be quenched by water, dissolved oxygen, copper(II) and ferrocyanide ions. The DNA binding is found to hardly alter the dynamic quenching of [Ru(bpy)2(atatp)]2+ by oxygen at a low DNA-to-Ru(II) molar ratio (r=0.83), allowing [Ru(bpy)2(atatp)]2+ to keep a basically unchanged oxygen quenching constant, as well as endow the photo-induced electron transfer between [Ru(bpy)2(atatp)]2+ and copper(II) cations, and weaken the electrostatic attraction of [Ru(bpy)2(atatp)]2+ with ferrocyanide anions. In addition, the DNA condensation induced by [Ru(bpy)2(atatp)]2+ can protect the DNA oxidative damage against superoxide anion and hydroxyl radical toxicity. The present results could provide a versatile platform for better fabrication of optoelectronic devices.