A quinoline-based tripodal fluororeceptor for citric acid

The quinoline-based tripodal fluororeceptor 1 has been designed and synthesized for the detection of citric acid in less polar solvents. Receptor 1 shows monomer emission quenching followed by excimer emission upon hydrogen bond-mediated complexation of citric acid. In comparison, receptor 2, in presence of the same acid, gives rise to a decrease in the monomer emission of the naphthyl moiety without showing any peak for the excimer. Receptor 1 is found to bind citric acid more strongly than receptor 2 in CHCl3.