252Cf plasma desorption mass spectrometric study of the inclusion complexes of cyclodextrins with coumarins

Abstract

252Cf plasma desorption mass spectrometry was used to investigate the formation of complexes of 7-amino-4-methylcoumarins with β- and γ-cyclodextrins. The individual substances and their co-ground mixtures were analyzed by plasma desorption ionization. In the negative-ion mass spectra of cyclodextrins highly characteristic fragmentation peaks were detected, and a scheme for the fragmentation pathway is proposed. The inclusion complex of 7-amino-4-methylcoumarin with β-cyclodextrin was obtained, and the peak corresponding to the complex was observed in the PDMS spectra. Various modes of inclusion of the coumarins into cyclodextrins, that can result in stable complex formation, are discussed in the light of molecular mechanics calculations. In spite of the possibility in principle of the inclusion of 7-amino-4-methylcoumarin into β-cyclodextrin, and of 7,N,N-diethyl-amino-4-methylcoumarin into γ-cyclodextrin, the complexes of these compounds appear to be insufficiently stable and they decomposed under the desorption/ionization conditions. © 1997 John Wiley & Sons, Ltd.