Inculcating total selectivity for fluoride in pyrene based chromogenic receptors: An experimental and theoretical study

Three simple Schiff base receptors 1–3 containing pyrene skeletons have been designed and synthesized. The intramolecular hydrogen bonding between aldimine N-atom and phenolic OH of these Schiff bases were found to play a crucial role towards their sensing behavior against fluoride. The receptor 3 exhibited total selectivity towards fluoride in acetonitrile. The basis of the above designing at the molecular orbital level was studied through density functional theory (DFT) and time dependent density functional theory (TD–DFT). The observed structure dependence of the binding selectivity may provide guidelines for the development of new colorimetric/fluorescent sensors for F− of further high selectivity.