An Experimental and Computational Study of the Gas-Phase Structures of Five-Carbon Monosaccharides

Abstract

The gas-phase structures of five five-carbon monosaccharides (d-ribose, d-lyxose, 2-deoxy-d-ribose, d-xylose, and d-arabinose) were studied via ion−molecule reactions with dimethoxyphosphenium ion and 1,3-dioxolane-2-phosphenium ion in a Fourier transform ion cyclotron resonance mass spectrometer. These reagent ions have been earlier demonstrated to be sensitive to the three-dimensional structures of diastereomeric vicinal diols. They were found to display unique reactivity toward each monosaccharide. The results indicate that the gaseous monosaccharides are cyclic molecules. On the basis of a comparison of the reactions of monosaccharides introduced into the gas phase via two different methods, laser-induced acoustic desorption (LIAD) and thermal desorption, the monosaccharides are concluded to maintain their crystalline structure, a pyranose form, throughout the evaporation procedure. For all the monosaccharides in this study except for d-lyxose, the lowest-energy structure found computationally using d...