Clathrates and inclusion compounds. Part I. Infrared and Raman studies of several β-quinol (hydroquinone) clathrates

Abstract

Infrared (4000–200 cm^–1) and Raman (3700–50 cm^–1) spectra are reported for α- and β- quinol, and for β-quinol clathrates containing the following guest molecules: N₂, O₂, HCl, HBr, CO₂, SO₂, H₂S, C₂H₂, HCO₂H, CH₃OH, CH₃CN, and CD₃CN. Comparison of the room-temperature and the low-temperature (77 K) Raman spectra of the HCl and HBr clathrates indicates a rotational motion of these guest molecules in the host lattice. The results are less conclusive for the N₂ and O₂ guest molecules due to the smaller values of their rotational constants. The guest-molecule vibrational frequencies are, in general, closer to the vapour-phase values than to the liquid-or solid-phase values. This is particularly true for the methanol and formic acid guest molecules, the spectra suggesting that these molecules are present as the monomeric species in the host cavities.