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 "RuCl(3)(dppb)" moieties have been prepared and characterized. The X-ray structure of the tetraruthenated {NiTPyP[RuCl(3)(dppb)](4)} porphyrin complex crystallizes in the triclinic space group P1. This structure is discussed and compared with the crystal data for the mer-[RuCl(3)(dppb)(py)]. The {TPyP[RuCl(3)(dppb)](4)} and {CoTPyP[RuCl(3)(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)(muCl(3))(2)}(2n)(4n2+) and {CoTPyP[Ru(dppb)](4)(muCl(3))(2)}(2n)(4n2+) on the electrode surface. The modified electrode with {CoTPyP[RuCl(3)(dppb)](4)} is very stable and can be used to detect organic substrates such as catechol.