INFRARED SPECTRA OF CARBOHYDRATES AT SUB-AMBIENT TEMPERATURES

The infrared spectra of a large number of carbohydrates, and of several other compounds of biological interest, have been recorded, for the range 2000-250 cm-1, at ∼ 110°K. In addition, the i.r. spectra of some selected sugars have been recorded over the range 4000-33 cm-1 at temperatures down to 20°K. The spectra of these compounds near 110°K, conveniently attained with boiling nitrogen, are shown to be of much better quality than those obtained at room temperature, and the spectral changes observed are much greater than those usually observed on cooling simpler compounds. Hence, the technique is useful for identification, characterization, and differentiation of complex compounds of biological interest. Several possible reasons for the results observed are considered. Although the effects of temperature cannot yet be quantitatively explained, they are apparently associated with hydrogne-bonding phenomena. © 1967.