it is confirmed by means of infrared spectroscopy that adsorption of sulphur dioxide on the layers obtained on the basis of the nitroxide radical 2-(4'-dimethylaminophenyl)-4,4,5,5 -tetramethylimidazoline-3-oxide-1-oxyl results in the formation of the adsorption complex (AC). The IR transmission spectra of the layers exhibit shifts of the frequencies of normal vibrations of the perturbed SO2 molecule in the adsorption complex, which suggests that this complex is formed at the oxyl group but not at the amine one, as it is the case with substituted amines. This is in good agreement with the results of semi-empirical modeling of the AC structure by means of MM2. It is demonstrated experimentally that the formation of AC is a reversible reaction at room temperature. (c) 2006 Elsevier B.V. All rights reserved.