Electrogenerated Chemiluminescence of the Tris(2,2′-bipyridine)ruthenium(II)/Tri-<i>n</i>-propylamine (TPrA) System: Crucial Role of the Long Lifetime of TPrA<sup>•+</sup> Cation Radicals Suggested by Electrode Surface Effects
Zuofeng Chen
Yanbing Zu
10.1021/jp802873e.s001
https://acs.figshare.com/articles/journal_contribution/Electrogenerated_Chemiluminescence_of_the_Tris_2_2_bipyridine_ruthenium_II_Tri_i_n_i_propylamine_TPrA_System_Crucial_Role_of_the_Long_Lifetime_of_TPrA_sup_sup_Cation_Radicals_Suggested_by_Electrode_Surface_Effects/2905603
We describe the effects of electrochemical pretreatment of glassy carbon electrodes (GCEs) on the electrogenerated chemiluminescence (ECL) of the Ru(bpy)<sub>3</sub><sup>2+</sup> (bpy = 2,2′-bipyridine)/tri-<i>n</i>-propylamine (TPrA) system. It has been found that the oxidation of TPrA at the anodically pretreated GCEs became more facile, while the intensity of ECL could be greatly suppressed. The contravention between the electrochemical reaction kinetics and the light emission intensity of the coreactant ECL system was reported for the first time and has been attributed to the rapid deprotonation of TPrA<sup>•+</sup> cation radicals by the aid of oxygen-containing surface species formed on the GCE during the pretreatment. Because the lifetime of TPrA<sup>•+</sup> was reduced, the products of the deprotonation reaction, TPrA<sup>•</sup> free radicals, would be more subject to oxidative consumption on the electrode subsequently, leading to weaker ECL signals. When the ECL was produced mainly following a catalytic route, however, the electrode surface effect was much less significant. This study suggests that the long lifetime of TPrA<sup>•+</sup> cation radicals may be crucial for the intense light emission, which allows a sufficient amount of highly reducing intermediate radicals, TPrA<sup>•</sup>, to participate in the ECL process within a relatively thick reaction layer before being destroyed by the electrode.
2008-10-23 00:00:00
Crucial Role
light emission intensity
Electrogenerated Chemiluminescence
anodically pretreated GCEs
deprotonation reaction
ECL process
electrochemical pretreatment
TPrA
light emission
Long Lifetime
Electrode Surface EffectsWe
radical
electrogenerated chemiluminescence
reaction layer
coreactant ECL system
electrochemical reaction kinetics
ECL signals
carbon electrodes
oxidative consumption
electrode surface effect