Facile synthesis of anthracene-appended amino acids as highly selective and sensitive fluorescent Fe 3+ ion sensors

Abstract

We designed new fluorescent chemical sensors for Fe 3+ ion detection, by conjugating amino acids as receptors into an anthracene fluorophore. The conjugates were synthesized in solid phase by Fmoc-chemistry. Fluorescence sensors containing Asp ( 1) and Glu ( 2) both had exclusive selectivity for Fe 3+ in 100% aqueous solution and in a mixed organic–aqueous solvent system. Other metal ions did not interfere with the detection ability of the sensors for Fe 3+. The sensors detect Fe 3+ ions via a chelation-enhanced fluorescent quenching effect. The binding affinity, reversible monitoring, and pH sensitivity of the sensors were investigated. In addition, detection of fluoride ion among halide ions was done by a chemosensing ensemble method with 1– Fe 3+ and 2– Fe 3+ complexes.