Photophysical, photostability, and ROS generation properties of new trifluoromethylated quinoline-phenol Schiff bases.

A new series of ten examples of Schiff bases, namely ( E )-2-(((2-alkyl(aryl/heteroaryl)-4-(trifluoromethyl)quinolin-6-yl)imino)methyl)phenols 3 , was easily synthesized with yields of up to 91% from the reactions involving a series of 2-(R-substituted) 6-amino-4-(trifluoromethyl)quinolines 1 and 4(5)-R 1 -substituted salicylaldehydes 2 - in which alkyl/aryl/heteroaryl for 2-R-substituents are Me, Ph, 4-MeC 6 H 4 , 4-FC 6 H 4 , 4-NO 2 C 6 H 4 , and 2-furyl, and R 1 -substituents are 5-NEt 2 , 5-OCH 3 , 4-Br, and 4-NO 2 . Complementarily, the Schiff bases showed low to good quantum fluorescence yield values in CHCl 3 (Φ f = 0.12-0.80), DMSO (Φ f = 0.20-0.75) and MeOH (Φ f = 0.13-0.85). Higher values of Stokes shifts (SS) were observed in more polar solvents (DMSO; 65-150 nm and MeOH; 65-130 nm) than in CHCl 3 (59-85 nm). Compounds 3 presented good stability under white-LED irradiation conditions and moderate ROS generation properties were observed.