Electrochemistry and electrochemiluminescence of stable tris(2,2′-bipyridyl)ruthenium(II) monolayer assembled on benzene sulfonic acid modified glassy carbon electrode

An electrochemically stable monolayer of tris(2,2′-bipyridyl)ruthenium(II) was obtained for the first time. It was based on the electrostatic attachment of Ru(bpy)32+ to the benzene sulfonic acid monolayer film, which was covalently bound onto glassy carbon electrode by the electrochemical reduction of diazobenzene sulfonic acid. The surface–confined Ru(bpy)32+ underwent reversible surface process, and reacted with the coreactant, tripropylamine, to produce electrochemiluminescence. In view of the stability of the electrode, the results strongly suggested that light was emitted from the surface–confined Ru(bpy)32+, not from the detached Ru(bpy)32+. The Ru(bpy)32+ modified electrode was used to the determination of tripropylamine. It showed good linearity in the concentration range from 5 μM to 1 mM with a detection limit of 1 μM (S/N=4). The good stability of the Ru(bpy)32+ modified electrode also showed that the benzene sulfonic acid monolayer film prepared can be served as an excellent support to construct multilayers.