A rational approach to fluorescence turn-on sensing of α-amino-carboxylates

A rational approach to fluorescence turn-on sensing of amino carboxylates is described, which primarily relies on the perturbation of the quenching n-pi* transiton energy level of a carbonyl ionophore relative to the pi-pi* transition energy level of an anthracene in the sensor. The anthracene-based bis (trifluoroacetylcarboxanilide) sensor is structurally simple but selectively senses alpha-amino acids as their carboxylate forms over beta and gamma-homologues, by forming a (1:1)-cyclic adduct with a large fluorescence enhancement factor of 110.