Homogeneous oxidation of trialkylamines by metal complexes and its impact on electrogenerated chemiluminescence in the trialkylamine/Ru(bpy)(3)(2+) system

The oxidation of triethylamine and tripropylamine was investigated in aqueo us solution by measurement of the direct oxidation at microelectrodes or by redox catalysis at ultramicroelectrodes. An effect of pH on the homogeneou s or direct oxidation was observed. In the presence of an electrogenerated oxidant such as Ru(bpy)(3)(3+), the oxidation of the amines could be achiev ed homogeneously. This was studied with metal complexes of different E-o [R u(bpy)(3)(3+), Fe(bpy)(3)(3+), Mo(CN)(8)(3-), Ru(CN)(6)(3-)]. When Ru(bpy)( 3)(3+) was the oxidant, the production of electrogenerated chemiluminescenc e (ECL) occurred. This homogeneous ECL generation was studied and the diffe rence in ECL intensity was related to the ease of oxidation of the amine an d of its intermediate radical.