The pH plays a foremost role in many biological and chemical processes, so their determination is very important. In this manuscript, an easy-to-prepare pyridoxal derived Schiff base L was investigated for the fluorescent sensing of pH. The weakly emissive L in DMSO turned to red emissive L with the increase in the poor solvent fraction in DMSO because of the combined effects of the aggregation-induced emission (AIE) and excited-state intramolecular proton-transfer (ESIPT). The formation of needle-like self-aggregates of L was examined by SEM analyses. Also, the tendency to form self-aggregates was investigated by DFT calculations. The self-aggregates of L in mixed DMSO:HEPES medium containing 95% HEPES was applied for the fluorescent sensing of pH. The red-emissive self-aggregates of L in the physiological pH turned to green emissive due to the deprotonation of pyridoxal-OH. The fluorescence titration data at different pH was analysed to estimate a pK_a value of 9.08 for the pyridoxal-OH.

pH在许多生物和化学过程中起着最重要的作用，因此确定它们非常重要。在此手稿中，研究了一种易于制备的吡x醛衍生的席夫碱L，用于pH值的荧光检测。由于聚集诱导发射（AIE）和激发态分子内质子转移（ESIPT）的共同作用，DMSO中的弱发射L随DMSO中不良溶剂分数的增加而变为红色发射L。通过SEM分析检查了L的针状自聚集体的形成。此外，通过DFT计算研究了形成自聚集体的趋势。L的自聚集将含有95％HEPES的DMSO：HEPES混合培养基中的H2O3用于荧光检测pH。由于吡ido醛-OH的去质子化，在生理pH值下L的红色发射自聚集体变为绿色发射体。分析了不同pH下的荧光滴定数据，得出吡ido醛-OH的pK _a值为9.08。