Ratiometric fluorescent pH probes based on aggregation-induced emission-active salicylaldehyde azines

自聚荧光增强的水杨醛吖嗪比率式pH荧光探针

Xiaofeng Ma, Jinghui Cheng, Jiaoyan Liu, Xiangge Zhou and Haifeng Xiang*

New J. Chem., 2015, 39 (1), 492 - 500.

A series of luminescent salicylaldehyde azines (SAs) containing different electron-accepting
substituents (−NO2, −F, and −Cl), electron-donating substituents (−OMe and −NEt2), and π-
extended system (naphthalene ring) are prepared for the application of fluorescent pH probes.
These SAs inheriting the aggregation-induced emission (AIE) features display strong blue,
green, and red fluorescence with large Stokes shifts in water and solid. Combining advantages
of AIE and chemical reactivity of phenol towards OH−/H+, most of the SAs can be used as
ratiometric fluorescent pH probes with a broad pH range (2−14) in water and solid (test paper).
Moreover, the inherent relationships between their chemical structures and AIE
properties/pKa values (7.5−13.3) are studied, which provide unequivocal insights for the
design of AIE-active dyes and their applications.