MOLECULAR RECOGNITION BY SELF-ASSEMBLED MONOLAYERS OF CAVITAND RECEPTORS

It is shown by angle-resolved x-ray photoelectron spectroscopy that ca vitands derived from resorcin[4]arenes provided with four dialkylsulfi de chains form stable monolayers on gold surfaces that are well organi zed by self-assembly. The cavitand headgroups at the surface of the re sorcin[4]arene monolayer act as molecular recognition sites for small organic molecules with remarkable selectivity for perchloroethylene (C 2Cl4). Comparative thermal desorption experiments indicate binding sit es with high interaction energies of C2Cl4 at the surface of the resor cin[4]arene monolayers. Fast and reversible ''host-guest'' interaction s were found by the monitoring of extremely small mass changes (in the nanogram range) with a quartz microbalance oscillator provided with g old electrodes coated by resorcin[4]arene monolayers.