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-π* transition energy level of a carbonyl ionophore relative to the π-π* transition energy level of an anthracene in the sensor. The anthracene-based bis(trifluoroacetylcarboxanilide) sensor is structurally simple but selectively senses α-amino acids as their carboxylate forms over β- and γ-homologues, by forming a (1:1)-cyclic adduct with a large fluorescence enhancement factor of 110.