Accessible Synthesis Methods and Physicochemical Properties of Quinoline-Derived Schiff Bases

Objective: Quinoline derivatives have extensively been used for both pharmaceutical agents and as fluorescent dyes for bioimaging. However, typical synthesis of quinoline derivatives is generally through expensive methods at high temperatures. Methods: In the present study, an inexpensive and accessible method for the synthesis of Schiff bases based on 6-amino-4-hydroxy-2-methylquinoline was developed by condensing the amino group at the sixth position of quinoline with the aldehyde group of hydroxybenzaldehydes. Results and Discussion: Quinoline-based Schiff bases were found to exhibit significant intramolecular fluorescence with charge transfer with Stokes shifts. Conclusions: Studies of the physicochemical properties of the synthesized compounds have shown that the quinolinebased Schiff bases have luminescent properties of aggregation-induced emission (AIE). They emit short-wave blue-green light like many other water-soluble AIE luminogens.