Rigid-induced aggregated annihilation electrochemiluminescence of 1,2,3-triaryl-substituted indoles in aqueous phase

Aggregation-induced electrochemiluminescence (AIE-ECL) have currently emerged as a hot research issue owing to significantly solve the problems of aggregation-caused quenching (ACQ) and water-insolubility for most organic luminescent probes. However, the current AIE-ECL systems can only be carried out under the promotion of co-reactant. Undoubtedly, the introduction of additional co-reactant will bring a series of problems, such as difficult operation, interference detection, and complex mechanism. In this work, benefiting from the luminescence-enhanced strategy based on rigid structure and aromaticity, we reported the first co-reactant-free annihilation AIE-ECL system of some 1,2,3-triaryl-substituted indoles. There were two strong ECL emission peaks for four indoles in the anode and cathode regions respectively. It was found that electron-donating o-methoxy-substituted indole with the highest steric hindrance showed the best ECL performance. This study not only tackles the inconvenience from the additional co-reactant to the AIE-ECL system, but also enriches the indole and AIE research.