On an Electrode Modified by a Supramolecular Ruthenium Mixed Valence (Ru^II/Ru^III) Diphosphine-Porphyrin Assembly

Three novel polymetallic ruthenium (III) meso-tetra(4-pyridyl)porphyrins containing peripheral “RuCl3(dppb)” moieties have been prepared and characterized. The X-ray structure of the tetraruthenated {NiTPyP[RuCl3(dppb)]4} porphyrin complex crystallizes in the triclinic space group P1̅. This structure is discussed and compared with the crystal data for the mer-[RuCl3(dppb)(py)]. The {TPyP[RuCl3(dppb)]4} and {CoTPyP[RuCl3(dppb)]4} porphyrins were used to obtain electrogenerated films on ITO and glass carbon electrode surfaces, respectively. Such tetraruthenated porphyrins form films of a mixed-valence species {TPyP[Ru(dppb)]4(μCl3)2}2n4n2+ and {CoTPyP[Ru(dppb)]4(μCl3)2}2n4n2+ on the electrode surface. The modified electrode with {CoTPyP[RuCl3(dppb)]4} is very stable and can be used to detect organic substrates such as catechol.