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Channel- and layer-type anionic host structures in inclusion compounds of urea, tetraalkylammonium
1Department of Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Peoples' Republic of China.
Abstract:
New crystalline adducts of tetraalkylammonium terephthalate/trimesate with urea and water molecules result from hydrogen-bond directed assembly of complementary acceptors and donors, and the anionic host lattices are described using the graph-set notation to identify distinct hydrogen-bonding motifs and patterns. Tetra-n-butylammonium terephthalate-urea-water (1/6/2), C46H104N14O12 (1), triclinic, space group P1, a = 8.390 (2), b = 9.894 (2), c = 18.908 (3) A, alpha = 105.06 (2), beta = 94.91 (1), gamma = 93.82 (2)o, Z = 1, is composed of hydrogen-bonded terephthalate-urea layers, which are intersected by urea layers to generate a three-dimensional network containing large channels for accommodation of the cations. Tetraethylammonium terephthalate-urea-water (1/1/5), C25H58N4O10 (2), triclinic, P1, a = 9.432 (1), b = 12.601 (1), c = 14.804 (1) A, alpha = 79.98 (1), beta = 79.20 (1), gamma = 84.18 (1)o, Z = 2, has cations sandwiched between hydrogen-bonded anionic layers. Tetraethylammonium trimesate-urea-water (1/2/7.5), C35H86N7O15.5 (3), triclinic, P1, a = 13.250 (1), b = 14.034 (1), c = 15.260 (1) A, alpha = 72.46 (1), beta = 78.32 (1), gamma = 66.95 (1)o, Z = 2, manifests a layer-type structure analogous to that of (2). Tetra-n-propylammonium hydrogen trimesate-urea-water (1/2/5), C35H78N6O13 (4), orthorhombic, Pna2(1), a = 16.467 (3), b = 33.109 (6), c = 8.344 (1) A, Z = 4, features hydrogen trimesate helices in a three-dimensional host architecture containing nanoscale channels each filled by a double column of cations.