Fluorescent 4-hydroxystyryl dyes are useful for many biomedical and pharmaceutical assays, and other analyte sensing applications. However, these dyes often suffer from limited applicability in analytical and bioanalytical utilization due to insufficient water-solubility, high acid-ionization constants (pK_a) and short-wavelength absorption and emission. To solve these issues, a series of new, water-soluble 4-hydroxystyryl and longer-wavelength 4-hydroxyphenyl-butadienyl dyes were synthesized and the spectral and protolytic properties were studied. These new dyes contain electron-withdrawing substituents ortho to the triggering 4-hydroxyl group. The introduction of the cyano and formyl groups was found to decrease the pK_a and extend the pH-sensing region of these fluorophores. In respect of the molecular structure, these dyes exhibit either a “turn-on” activatable fluorescence, or a dual-fluorescence that enables ratiometric measurements. The 4-hydroxyphenyl-butadienyl dye was evaluated for fluorescence monitoring of drug delivery. These new dyes are promising fluorophores for acidity measurements and other sensing applications.

荧光4-羟基苯乙烯基染料可用于许多生物医学和药物分析以及其他分析物检测应用。但是，由于水溶性不足，酸电离常数（pK _a）高以及短波长吸收和发射，这些染料在分析和生物分析应用中的适用性常常受到限制。为了解决这些问题，合成了一系列新型的水溶性4-羟基苯乙烯基和更长波长的4-羟基苯基丁二烯基染料，并研究了其光谱和蛋白水解性能。这些新染料含有与引发4-羟基邻位的吸电子取代基。发现引入氰基和甲酰基会降低pK _a并扩展了这些荧光团的pH敏感区域。就分子结构而言，这些染料显示出“开启”可激活的荧光，或者是能够进行比率式测量的双重荧光。评价4-羟基苯基-丁二烯基染料用于药物递送的荧光监测。这些新染料是用于酸度测量和其他传感应用的有前途的荧光团。