A new redox site as an alternative to ferrocene to study electron transfer in self-assembled monolayers

The cyclometallated ruthenium complex [Ru(bpy)2(pp)]+ (bpy: 2,2'-bipyridine; pp: 2-(2'-ylphenyl)pyridine) was easily grafted to a omega-alkanethiol and the resulting compound was coadsorbed with 11-hydroxyundecanethiol on gold yielding a Self-Assembled Monolayer (SAM) in an analogous manner as for a ferrocene derivative, as shown by impedance spectroscopy; the kinetics of the heterogeneous electron transfer were shown to be very fast, compared to ferrocene, which makes this new redox site a promising candidate for further studies about molecular wires.