Previously reported fluorescent sensors for Th⁴⁺ experienced emission quenching or generated false positive signal upon aggregate formation in aqueous media. Herein, a simple and novel thorium sensor (CDB-BA) based on cyanodistyrene structure was designed and synthesized, which integrated the highly emitting characteristic of AIE effect and off-on response of PET modulation for the first time to construct the “turn-on” fluorescent probe for Th⁴⁺. Besides excellent selectivity, CDB-BA exhibited remarkable fluorescent enhancement which was linearly related to the concentration of Th⁴⁺ in the range of 0.25 to 8 μM. The detection limit was attained 0.074 μM, which was lower than that of most previously reported sensors. The mechanism of tris-chelate complex of CDB-BA with Th⁴⁺ was confirmed by mass spectra, IR spectra and DFT calculation. The excellent Th⁴⁺ sensing ability of CDB-BA was successfully applied to detecting Th⁴⁺ on TLC plates, in real water samples and living-cell imaging. This work suggested that the combination of AIE and PET photophysical mechanism could offer the merits of minimized background and enhanced signal fidelity to develop novel “turn-on” fluorescent probe in complicated aqueous environment and biological research.

先前报道的用于Th ^4+的荧光传感器在水介质中形成聚集体时会发生发射猝灭或生成假阳性信号。本文设计并合成了一种基于氰基二苯乙烯结构的新颖新颖的sensor传感器（CDB-BA），首次结合了AIE效应的高发射特性和PET调制的开通响应，从而构建了“开通” Th ^4+的荧光探针。除了出色的选择性外，CDB-BA还表现出显着的荧光增强作用，与Th ⁴⁺的浓度呈线性关系。范围为0.25至8μM。检出限达到0.074μM，低于以前报告的大多数传感器的检出限。通过质谱，红外光谱和DFT计算证实了CDB-BA与Th ⁴⁺的三螯合物的形成机理。CDB-BA出色的Th ⁴⁺感测能力已成功应用于在TLC平板上，真实水样和活细胞成像中检测Th ⁴⁺。这项工作表明，AIE和PET光物理机制的结合可以提供最小化背景和增强信号保真度的优点，从而在复杂的水环境和生物学研究中开发出新颖的“开启”荧光探针。