Amino acids based on 2,4,5-triarylimidazoles: synthesis and evaluation as new chemosensors for ion recognition

Abstract

N-tert-butyloxycarbonyl-4-formylphenylalanine methyl ester and appropriate heterocyclic diones were used in the synthesis of novel fluorescent unnatural amino acids, namely 2,4,5-triarylimidazolyl-alanines. These new compounds were fully characterised by the usual spectroscopic techniques, such as IR and NMR. The photophysical properties of the amino acids were evaluated by UV-Vis absorption and fluorescence spectroscopy in solvents of different character. Interaction studies with biologically and analytically important ions such as F-, OH-, Cu2+ and Fe3+, through spectrophotometric and spectrofluorimetric titrations were carried out to assess their potential as chemosensors.