| Abstract: | The anomers of 1-O-n-octyl-D-glucopyranosides exhibit different crystal packing and thermodynamic properties. Crystallization either from solution or by epitaxy of the α-anomer resembles that of other amphiphiles, such as lysolecithin, and is isostructural to the decyl homologue. The β-anomer crystallizes into a unique form, independent of conditions, with the longest cyrstallographic axis parallel to the best developed crystal face. Both compounds exhibit two phase transitions, one near 70°C, the other above 100°C. The latter corresponds to melting to an isotropic liquid for both forms, but the former is distinctly different for the two anomers. Thus, birefringence is lost only with the β-anomer, while the enthalpy change is two-fold larger for the α-anomer. The crystal packing of the two compounds are thus clearly different. |
