Keto-Salicylaldehyde Azine: Asymmetric substituent effect on their optical property via electron-donating group insertion
Organic fluorescent probes have attracted more attention owing to their high sensitivity and recognition ability with structurally adjustable flexibility via presenting in the form of visualization. Salicylaldehyde azine (SAA) and its derivatives exhibit great potential for application, but their synthesis steps of asymmetric compounds for serving multiple functions are cumbersome with lower yields. As an alternative building block, Keto-Salicylaldehyde Azine (KSA) is developed in our group for constructing various AIEgens via ESIPT process to detect some cellular organelles and specific metal ions. For illuminating the structure-property relationship of two asymmetric sides in KSA unit, DPAS is employed as a model and introduced N,N-diethyl group with electron-donating effect to its salicylaldehyde side (S-terminal) and diphenylketone side (K-terminal), and the three new compounds show different photophysical properties, especially in AIE performance and metal ion responsiveness, implying their intrinsic electronic structure that would be easily affected by the asymmetric substitution effect. Therefore, this work is a meaningful and valuable reference for KSA-modification on expanding fluorescent probes with various functions via purposeful regulation of chemical structure in the K-terminal or S-terminal.
- This article is part of the themed collection: 2019 Journal of Materials Chemistry C HOT Papers