| Summary: | We report self-assembled novel triphenylphosphonium-conjugated dicyanostilbene-based as selective fluorescence turn-on probes for <sup>1</sup>O<sub>2</sub> and ClO<sup>−</sup>. Mono- or di-triphenylphosphonium-conjugated dicyanostilbene derivatives <b>1</b> and <b>2</b> formed spherical structures with diameters of ca. 27 and 56.5 nm, respectively, through π-π interaction between dicyanostilbene groups. Self-assembled <b>1</b> showed strong fluorescent emission upon the addition of <sup>1</sup>O<sub>2</sub> and ClO<sup>−</sup> compared to other ROS (O<sub>2</sub><sup>−</sup>, <sup>•</sup>OH, NO, TBHP, H<sub>2</sub>O<sub>2</sub>, GSH), metal ions (K<sup>+</sup>, Na<sup>+</sup>), and amino acids (cysteine and histidine). Upon addition of <sup>1</sup>O<sub>2</sub> and ClO<sup>−</sup>, the spherical structure of <b>1</b> changed to a fiber structure (8-nm wide; 300-nm long). Upon addition of <sup>1</sup>O<sub>2</sub> and ClO<sup>−</sup>, the chemical structural conversion of <b>1</b> was determined by FAB-Mass, NMR, IR and Zeta potential analysis, and the strong emission of the self-assembled <b>1</b> was due to an aggregation-induced emission enhancement. This self-assembled material was the first for selective ROS as a fluorescence turn-on probe. Thus, a nanostructure change-derived turn-on sensing strategy for <sup>1</sup>O<sub>2</sub> or ClO<sup>−</sup> may offer a new approach to developing methods for specific guest molecules in biological and environmental subjects.
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