A series of triazaborolopyridiniums (TBP) has been synthesized by varying electron-tunning substituents. The TBP derivatives with electron-withdrawing groups, including cyano, and nitro moieties, exhibited solvatochromic properties due to the internal charge transfer (ICT) effect. The density functional theory (DFT) calculations suggested that the nitro-substituted TBP derivative (8) possessed the highest change in dipole moment upon excitation (Δμ) yielding the most distinctly large stokes shift and low fluorescence quantum yields as the solvent polarity increased. In addition, compound 8 displayed an apparent fluorescence quenching in the presence of hydrogen bond-donating molecules (e.g. methanol, ethanol, water); therefore, it was chosen to be utilized as a trace water detector in four common solvents, including, tetrahydrofuran (THF), acetonitrile (MeCN), acetone, and dimethylformamide (DMF). The satisfying linear relationship between the ratios of the blank fluorescence intensity to the decreased fluorescence intensity (I₀/I) and the trace water content was used to determine the limits of detection (LOD) of water. The low LODs (0.028% for THF, 0.013% for MeCN, 0.021% for acetone, and 0.045% for DMF) confirmed the capability of compound 8 as a super-sensitive water sensor in organic solvents.

通过改变电子配位取代基合成了一系列三氮杂硼吡啶鎓（TBP）。具有吸电子基团（包括氰基和硝基部分）的TBP衍生物由于内部电荷转移（ICT）效应而具有溶剂变色性质。密度泛函理论（DFT）计算表明，随着溶剂极性的增加，硝基取代的TBP衍生物（8）在激发时偶极矩具有最大变化（Δμ），产生最大的斯托克斯位移，而荧光量子产率却较低。另外，化合物8在存在氢键供体分子（例如甲醇，乙醇，水）的情况下，表现出明显的荧光猝灭；因此，它被选择用作四种常见溶剂中的痕量水检测器，包括四氢呋喃（THF），乙腈（MeCN），丙酮和二甲基甲酰胺（DMF）。空白荧光强度与降低的荧光强度之比（I ₀ / I）与痕量水含量之间的令人满意的线性关系用于确定水的检出限（LOD）。低LOD（THF为0.028％，MeCN为0.013％，丙酮为0.021％，DMF为0.045％）证实了化合物8作为有机溶剂中超灵敏水传感器的功能。