Inclusion compounds of phenol derivatives with cyclodextrins: a combined spectroscopic and thermal analysis

Abstract

Inclusion compounds involving α-, β- and γ-cyclodextrins (α-, β- and γCD) and phenol derivatives, namely 3-methoxyphenol (3MeOPh), 2-methoxyphenol (2MeOPh) and 3-methylphenol (3MePh), were investigated and characterized by combining Raman spectroscopy, ab initio calculations, DSC and TG analysis.

The effects of the inclusion process on the guest molecules and on the hydrogen bond interactions of the guests were studied by monitoring sensitive modes, such as CC and CH ring stretching modes. Moreover, the combined use of the data available from Raman spectra, computational methods and the known x-ray structures of similar compounds, allowed the proposal of most probable structures for the αCD inclusion compounds.

Both inclusion compounds of meta-substituted guests in αCD present unusual 1:2 or 2:3 stoichiometries. The Raman spectra of these inclusion compounds reveal the split of several modes, spread over the entire spectral range, indicating the presence of guest molecules inside and outside the CD cavity. Copyright © 2009 John Wiley & Sons, Ltd.