Hydrazine (N₂H₄) has been classified as an environmental contaminant and human carcinogen owing to its high toxicity. Exposed to high concentration of hydrazine can cause irreversible damage to human bodies. Hence, it is significant to explore an effective analytical method to selectively recognize and detect it. In this work, an intramolecular charge transfer (ICT) based probe 1 was designed and synthesized by condensation of V-shaped bis-coumarin and 4-bromobutyric acid. The V-shaped bis-coumarin with π-expanded system endowed the probe 1 larger stokes shift and superior tolerance to photobleaching. This “turn-on” probe exhibited a high selectivity towards hydrazine over other common ions and amine-containing species with a distinct fluorescent enhancement at 555 nm. It could rapidly detect hydrazine over a wide pH range and the detection limit was as low as 4.2 ppb. The large shift of absorption spectrum enabled it to detect hydrazine in real water samples and gas-state hydrazine by “naked-eyes".

肼（N ₂ H ₄）由于其高毒性而被分类为环境污染物和人类致癌物。暴露于高浓度的肼会导致对人体的不可逆转的伤害。因此，探索一种有效的分析方法以选择性地识别和检测它具有重要意义。在这项工作中，通过V型双香豆素和4-溴丁酸的缩合，设计并合成了基于分子内电荷转移（ICT）的探针1。带有π扩展系统的V形双香豆素赋予探针1更大的行程偏移和对光漂白的优异耐受性。与其他常见离子和含胺类物质相比，这种“接通”探针对肼具有较高的选择性，在555 nm处具有明显的荧光增强作用。它可以在很宽的pH范围内快速检测出肼，检出限低至4。2 ppb。吸收光谱的大位移使其能够通过“裸眼”检测实际水样中的肼和气态肼。