resumo
Inclusion compounds involving alpha-, beta- and gamma-cycloclextrins (alpha-, beta- and gamma CD) 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 C-C and C-H 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 alpha CD inclusion compounds. Both inclusion compounds of meta-substituted guests in alpha CD 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 (C) 2009 John Wiley & Sons, Ltd.
palavras-chave
CYCLOMALTOHEXAOSE ALPHA-CYCLODEXTRIN; BETA-CYCLODEXTRIN; CRYSTAL-STRUCTURE; RAMAN; COMPLEX; DENSITY; STATE
categoria
Spectroscopy
autores
Sardo, M; Amado, AM; Ribeiro-Claro, PJA
nossos autores
Mariana Coutinho Sardo
Investigador Auxiliar
Paulo Ribeiro-Claro
Professor Associado com Agregaçãoagradecimentos
The authors would like to acknowledge Wacker Chemie GmbH, Germany, for their kind offer of the cyclodextrin samples, and the Portuguese Foundation for Science and Technology (FCT) for the financial support - Loboratorio Associado CICECO and Unidade de Qufmica-Fisica Molecular. MS also acknowledges FCT for a Ph.D. grant - SFRH/BD/23400/2005.