Electrogenerated chemiluminescence reaction of tris(2,2′-bipyridine)ruthenium(II) with 2,5-dimethylthiophene as co-reactant in aqueous solution

A novel effective co-reactant for electrogenerated chemiluminescence (ECL) of Ru(bpy)32+ has been found. α-Position-dialkylated thiophene derivatives such as 2,5-dimethylthiophene (DMT) could be used as a co-reactant for Ru(bpy)32+ ECL. The reaction mechanism of the Ru(bpy)32+/DMT system was proposed on the basis of the identification of the reaction product, the relationship between the molecular structure and the chemiluminescent intensity, and the electrochemical study. The obtained reaction mechanism was similar to that of the Ru(bpy)32+/aliphatic tertiary amine system. Based on these results, the preliminary studies of the Ru(bpy)32+ ECL detection system using DMT as a co-reactant were performed. Under the optimal ECL conditions, the plot of ECL intensity versus the concentration of Ru(bpy)32+ was linear over the concentration range 1.0 × 10−8 to 1.5 × 10−7 M (determination coefficient = 0.9996).