Calix[4]arene-based enantioselective fluorescent sensors for the recognition of N-acetyl-aspartate

Two-armed chiral anion receptors (1 and 2), calix[4]arenes bearing dansyl fluorophore and (1R,2R)- or (1S,2S)-1,2-diphenylethylenediamine binding sites, were prepared and examined for their chiral amino acid anion binding abilities by the fluorescence spectra in dimethylsulfoxide (DMSO). The results of non-linear curve fitting indicate that 1 or 2 forms a 1 : 1 stoichiometry complex with N-acetyl-L- or D-aspartate by multiple hydrogen bonding interactions, exhibiting good enantioselective fluorescent recognition for the enantiomers of N-acetyl-aspartate, [receptor 1: K-ass(D)/K-ass(L) = 6.74; receptor 2: K-ass(L)/K-ass(D) = 6.48]. The clear fluorescent response difference indicates that receptors 1 and 2 could be used as a fluorescent chemosensor for N-Acetyl-aspartate.