Electrochemistry of a novel monoruthenated porphyrin and its interaction with DNA

Interactions of an anisomerous ruthenated porphyrin [Ru(MPyTPP)(bpy)2Cl]+ (where bpy = 2,2′-bipyridine, MPyTPP = 5-pyridyl-10,15,20-triphenyl porphyrin) with calf thymus DNA are studied using a tin-doped indium oxide (ITO) electrode. The RuIII/II redox reaction for the complex exhibits a surface-controlled electron transfer process in buffer solutions. There exists an obvious interaction of the adsorbed [Ru(MPyTPP)(bpy)2Cl]+ on an ITO electrode with DNA in the buffer solutions. The formal potential for [Ru(MPyTPP)(bpy)2Cl]2+/+ redox reaction is found to shift negatively in the presence of DNA compared with that in the absence of DNA. However, the current signals of [Ru(bpy)3]3+/2+ reaction exhibits a distinct catalytic enhancement to DNA, in contrast to the interactions of [Ru(MPyTPP)(bpy)2Cl]+with DNA.