Aggregation-Induced\nEnhanced Electrochemiluminescence from Organic Nanoparticles of Donor–Acceptor\nBased Coumarin Derivatives

Abstract

Organic\nnanoparticles (NPs) from donor–acceptor based coumarin derivatives,\n6-[4-(<i>N</i>,<i>N</i>-diphenylamino)­phenyl]-3-ethoxycarbonyl\ncoumarin (DPA-CM), with an average size of 5.82 nm, were synthesized\nby a facile reprecipitation method using water as a poor solvent and\ntetrahydrofuran as a good solvent. Red-shifted absorption, blue-shifted\nphotoluminescence emission, and aggregation-induced enhanced electrochemiluminescence\n(ECL) emission were observed for the DPA-CM NPs in aqueous solution\ncompared with the original DPA-CM in organic solution. The aggregation-induced\nenhanced ECL emission is ascribed to the combined effects of the small\nsize of the DPA-CM NPs, the restricted conformational relaxation in\nthe NPs, and the good stability of the cationic radical of DPA-CM.\nA strong and stable ECL emission is obtained at the DPA-CM NPs modified\nglassy carbon electrode in the presence of tri-<i>n</i>-propylamine,\nand the ECL intensity of the DPA-CM NPs modified electrode is quenched\nlinearly in the range of 0.05–50 μM with detection limit\nof 0.04, 0.2, and 0.4 μM for ascorbic acid, uric acid, and dopamine,\nrespectively. This work shows an example of donor–acceptor\nbased organic NPs as ECL emitters and their analytical applications\nto monitor biomolecules.