CRYSTALLINE ORDER IN PROBABLY HOLLOW MICELLAR FIBERS OF N-OCTYL-D-GLUCONAMIDE

The molecular conformation of N-(1-octyl)-D-gluconamide in its helical micellar fibers is determined. The all anti conformation in three-dimensional crystals and the (4)G(+) conformation in DMSO solution served as references. Comparisons of C-13 CP/MAS solid-state NMR spectra of head-to-tail and tail-to-tail oriented crystals led to a (2)G(-) conformation for the gluconamide head groups and an all-anti conformation for the alkyl chains in the fibers. The latter result is confirmed by powder X-ray diffraction data and infrared spectra. Modeling of the micellar rod shows that there must be a gap of about 0.8-nm diameter in the center, probably in the form of a tunnel. A short discussion of other cylindrical bilayer crystals is given.