Quenching of the electrochemiluminescence of tris(2,2'-bipyridine)-ruthenium(II) by sodium diphenylamine-4-sulfonate.

Efficient quenching electrochemiluminescence (ECL) of the tris(2,2'-bipyridine)ruthenium(II)/tripropylamine (Ru(bpy)(3)(2+)/TPrA) system by a novel quencher, sodium diphenylamine-4-sulfonate (SDS), has been investigated. The quenching behaviors can be observed with a 100-fold excess of SDS over Ru(bpy)(3)(2+). The mechanism of quenching is believed to involve energy transfer from the excited-state Ru(bpy)(3)(2+*) to the dimer of SDS, which was formed after the electrochemical oxidation of SDS at the electrode surface. Photoluminescence experiments coupled with bulk electrolysis support formation of the SDS dimer upon electrochemical oxidation.