Isomeric 4-aminoantipyrine derivatives as fluorescent chemosensors of Al3+ ions and their molecular logic behaviour

Abstract

Aluminium ions are present in the human body and in the environment. Chemo-sensing of mobile aluminium ions is hence vital, and in this paper we report two isomeric 4-aminoantipyrine derivatives, as turn–on fluorescent Al3+ ion sensors. The compounds are synthesized as simple Schiff bases and characterized using UV–visible, IR, 1H NMR, 13C NMR and Mass spectroscopy. Selectivity of aluminium ions is displayed by the receptors when screened for binding against a pool of metal ions, and the magnitude of selectivity differs between the two chemo-sensors. The chemo-sensors show visible colour changes when binding Al3+ ions through PET (Photoinduced Electron Transfer) which make them colorimetric sensors. We propose the binding strength and the mode of binding of the metal ion to the chemo sensors. Further, the molecular logic behaviour of chemo-sensors with proton and Al3+ ions as inputs is also explored.