Unusual Hydrocarbon Chain Packing Mode and Modification of Crystallite Growth Habit in the Self-Assembled Nanocomposites Zinc−Aluminum-Hydroxide Oleate and Elaidate (cis- and trans- [Zn₂Al(OH)₆(CH₃(CH₂)₇CHCH(CH₂)₇COO^-)] and Magnesium Analogues

We report a novel packing mode specific to the cis unsaturated hydrocarbon chain in the title compound, a self-assembled layered double hydroxide−surfactant hybrid nanomaterial, and its influence on crystallite morphology and structure. The kink imposed by the cis double bond in oleate leads to partial overlap between chains on adjacent layers, with incomplete space filling, in contrast to the more usual (and more efficient) mono- and bilayer packings exhibited by the trans analogues. Incorporation of surfactant into the growing crystallite leads to a reversal of the usual LDH growth habit and results in crystallite shapes featuring ribbonlike sheets. The thermal decomposition behavior of the as-prepared organic/inorganic nanocomposites in air and N 2 is described.