Recognition of 1-phenylethylamine enantiomers by thin solid films of inherently chiral calix[4]arene.

The enantiodiscrimination properties of stereomerically pure inherently chiral calix[4]arene acetic acids, as well as their esters and amides in relation to 1-phenylethylamine stereoisomers in liquid and gaseous phases were studied by means of proton magnetic resonance spectroscopy (1 H NMR) and quartz crystal microbalance (QCM) techniques. Series of QCM sensors with thin films of inherently chiral calix[4]arenes, immobilized on the quartz resonator surfaces by spin-coating and spreading drop methods have been fabricated. It was shown that sensors based on calix[4]arene acetic acids are able to recognize R- and S-forms of 1-phenylethylamine in gaseous phase under concentration level of 10-400 ppm.