An Aggregation-Induced\nEmissive Platinum(II) Metallacycle\nas the Energy Donor of Rhodols for Ratiometric Detection of Hydrazine

Industry-produced hydrazine (N<sub>2</sub>H<sub>4</sub>) is released\ninto the environment, posing a major risk to human health and the\necosystem. Therefore, it is imperative to develop an effective and\nconvenient method for the detection of N<sub>2</sub>H<sub>4</sub>.\nHerein, artificial light-harvesting systems (ALHSs) for N<sub>2</sub>H<sub>4</sub> detection were constructed by applying an aggregation-induced\nemission-active platinum(II) metallacycle (<b>TPEMc</b>) as\nthe energy donor and rhodols (<b>P1</b>, <b>P2</b>, and <b>P3</b>) as the energy acceptors. The ratiometric fluorescence\nprobes based on ALHSs for N<sub>2</sub>H<sub>4</sub> showed obvious\nsignal amplification and lower limits of detection compared to those\nof rhodols (<b>P1</b>, <b>P2</b>, <b>P3</b>) alone.\nThe <b>TPEMc</b>–rhodols systems clearly demonstrated\na noticeable increase in fluorescence intensity at 550 nm and an obvious\nfluorescent color shift from cyan to yellow in the presence of N<sub>2</sub>H<sub>4</sub>. Fascinatingly, N<sub>2</sub>H<sub>4</sub> could\nbe visually and quantitatively detected in water by the <b>TPEMc</b>–rhodol systems paired with smartphone RGB analysis. Therefore,\nthe combination of platinum(II) metallacycle with rhodols is a promising\nstrategy for simple, sensitive, and visual detection of N<sub>2</sub>H<sub>4</sub>.