Molecular interactions and infrared dichroism of crystalline monosaccharides related to xylan

Abstract

The infrared spectra (4000-670 cm^-l) have been obtained of methyl β-D- xyloside and methyl 1-thio-β-D-xyloside in the form of single crystals and potassium chloride disks. Deuteration shifts in the disk spectra and polarization measurements in the single crystal spectra were used to assign the various bands to infrared-active fundamental modes. Molecular interactions in the crystals have been studied by comparing the observed dichroism with that predicted from a knowledge of the structures. Problems involved in elucidating the structures of crystalline carbohydrates, e.g. higher oligomers of xylan and cellulose, from studies of their infrared dichroism are discussed.