Enantioselective molecular sensing of aromatic amines using tetra-(S)-di-2-naphthylprolinol calix[4]arene

This paper presents new analytical data, and evidence of the fluorescence q uenching mechanism involved in enantioselective signals obtained with the c hiral host tetra-(S)-di-2-naphthylprolinol calix[4]arene. Excellent selecti vity is obtained with phenylglycinol and norephidrine in methanol, and samp les of unknown enantiomeric composition have been determined with an averag e error of 1.08 and 0.62%, respectively (n = 6), on the basis of a single f luorescence measurement. The absence of any quenching observed with the rel ated amines of phenylalaninol is attributed to a methylene spacer which inh ibits efficient interaction between the aryl group of the guest and the nap hthyl group of the host. The importance of the phenyl group of the guest in the quenching mechanism is confirmed by the complete absence of any quench ing effect with cyclohexylethylamine.