THE CRYSTAL-STRUCTURE AND THERMOTROPIC LIQUID-CRYSTAL PROPERTIES OF N-N-UNDECYL-D-GLUCONAMIDE

N-n-Undecyl-d-gluconamide, C17H35O6, crystallizes in space group P1, with one molecule in a unit cell a = 5.2267(6), b = 19.628(9), c = 4.7810(4) Å, a = 93.23(2), β = 95.60(1), γ = 89.58(2)°, V = 487.35 Å3, Dx = 1.19 g.cm-3. The crystal lattice is isostructural with N-n-heptyl-d-gluconamide having monolayer head-to-tail molecular packing. The molecules have a V-shaped conformation. The hydrogen bonding of the gluconamide moieties includes a four-link homodromic cycle. The transition to a smectic A liquid-crystal phase at 156.7° is preceded by two crystal-to-crystal phase transitions at 77.2° and 99.4°. The long d-spacing of the intermediate crystal phase of 39 Å, and the d-spacing of the liquid-crystal phase of 32 Å, are consistent with a transition to a bilayer head-to-head molecular packing. © 1990.