Institute of Analytical Chemistry and Food Chemistry, Graz University of Technology, Stremayrgasse 9, 8010, Graz, Austria.
Analyst. 2019 Mar 25;144(7):2393-2402. doi: 10.1039/c9an00118b.
New aza-BODIPY pH indicators with spectral properties modulated solely by photoinduced electron transfer (PET) are presented. The pH sensitive hydroxyl group is located in the meta-position of a phenyl substituent with respect to the aza-BODIPY core, which eliminates the conjugation to the chromophore. The new dyes show reversible "on"-"off" fluorescence response upon deprotonation of the receptor but no changes in the absorption spectrum, which is in contrast to state-of-the-art indicators of the aza-BODIPY family. This eliminates potential changes in the efficiency of the inner filter effect and Förster resonance energy transfer (FRET) and makes the new dyes suitable acceptors in light harvesting systems used for ratiometric pH imaging. The introduction of electron-withdrawing or electron-donating groups into the receptor results in a set of indicators suitable for measurements from physiological (pH 7) to very alkaline (pH 13) conditions. The new sensors are particularly promising for monitoring of pH changes in concrete, as was recently shown elsewhere.
本文介绍了一类新型的通过光诱导电子转移（PET）调控光谱性质的氮杂 BODIPY pH 指示剂。该指示剂的供电子基团是一个位于氮杂 BODIPY 核心苯环对位的羟基，与发色团之间没有共轭。该类新型染料在去质子化后表现出可逆的“开”-“关”荧光响应，而吸收光谱没有变化，这与目前最先进的氮杂 BODIPY 家族指示剂形成对比。这消除了内滤效应和Förster 共振能量转移（FRET）效率变化的潜在影响，使得新型染料适合用于比率 pH 成像的光收集系统中的受体。在受体中引入吸电子或供电子基团得到了一系列适合从生理（pH 7）到非常碱性（pH 13）条件下进行测量的指示剂。正如最近在其他地方所展示的，这些新型传感器在监测混凝土中的 pH 值变化方面具有广阔的应用前景。
