Single‐benzene fluorophores have attracted increasing interest owing to their simple molecular structure and unique photophysical properties. Developing novel single‐benzene fluorophores with facile synthesis, bright and tunable dual‐state emissions, and diversified functions is highly desirable. Herein, a strategy of controlling electron density on amino of 2,5‐diaminoterephthalates is proposed to modulate their dual‐state emission, acidichromism, Cu2+ detection, and lipid droplets (LDs) staining. A series of efficient dual‐state single‐benzene fluorophores based on 2,5‐diaminoterephthalate skeleton with tunable emissions in blue to red region and large Stokes shifts is facilely developed. The obtained fluorophores with various substituents on amino groups exhibit different acidichromism property. Two of fluorophores (ABB and ABM) with high electron density on amino groups exhibit high sensitivity and selectivity toward Cu2+ detection with a ratiometric and “turn‐off” fluorescence mechanism for ABM and ABB, respectively. The limit of detection for Cu2+ is determined to be 1.40 × 10−7 and 4.35 × 10−9 mol L−1 for ABB and ABM, respectively. Moreover, three of fluorophores (ABT, ABB, and ABM) with green to red emission display superior LDs‐targeting capability with high specificity, and brightness. This molecular design philosophy provides a new way of designing highly bright dual‐state fluorophores for practical applications.

中文翻译：

---

单苯荧光团：控制 2,5-对苯二甲酸二氨基酯的氨基上的电子密度，以操纵光学/电子特性，实现高效和多样化的功能


单苯荧光团由于其简单的分子结构和独特的光物理性质而引起了越来越多的兴趣。开发具有易于合成、明亮且可调的双态发射以及多样化功能的新型单苯荧光团是非常必要的。在此，提出了控制 2,5-二氨基对苯二甲酸酯氨基上的电子密度的策略，以调节其双态发射、酸变色、Cu2+检测和脂滴 (LD) 染色。轻松开发了一系列基于 2,5-二氨基对苯二甲酸酯骨架的高效双态单苯荧光团，具有蓝到红区域可调发射和大斯托克斯位移。所获得的氨基上具有不同取代基的荧光团表现出不同的酸显色特性。氨基上具有高电子密度的两种荧光团（ABB 和 ABM）对 Cu2+ 检测表现出高灵敏度和选择性，分别对 ABM 和 ABB 具有比例和“关闭”荧光机制。对于 ABB 和 ABM，Cu2+ 的检测限分别确定为 1.40 × 10−7 和 4.35 × 10−9 mol L−1。此外，三种具有绿色到红色发射的荧光团（ABT、ABB 和 ABM）显示出卓越的 LD 靶向能力，具有高特异性和亮度。这种分子设计理念为实际应用提供了一种设计高亮度双态荧光团的新方法。