Date Published: June 01, 2012
Publisher: International Union of Crystallography
Author(s): Christian Neis, Günter J. Merten, Kaspar Hegetschweiler.
The 2-hydroxycyclohexane-1,3,5-triaminium (= H3L3+) cation of the title compound, 3C6H18N3O3+·8Cl−·HSO4−·2H2O, exhibits a cyclohexane chair with three equatorial ammonium groups and one axial hydroxy group in an all-cis configuration. The hydrogen sulfate anion and two water molecules lie on or in proximity to a threefold axis and are disordered. The crystal structure features N—H⋯Cl and O—H⋯Cl hydrogen bonds. Three C3-symmetric motifs can be identified in the structure: (i) Two chloride ions (on the C3-axis) together with three H3L3+ cations constitute an [(H3L)3Cl2]7+ cage. (ii) The lipophilic C6H6-sides of three H3L3+ cations, which are oriented directly towards the C3-axis, generate a lipophilic void. The void is filled with the disordered water molecules and with the disordered part of the hydrogen sulfate ion. The hydrogen atoms of these disordered moieties were not located. (iii) Three H3L3+ cations together with one HSO4− and three Cl− counter-ions form an [(HSO4)(H3L)3Cl3]5+ cage. Looking along the C3-axis, these three motifs are arranged in the order (cage 1)⋯(lipophilic void)⋯(cage 2). The crystal studied was found to be a racemic twin.
The synthesis of a sulfate salt of H3L3+ as well as metal complex formation of L has been reported by Merten et al. (2012 ▶). For the synthesis of a diastereomeric form of L, see: Castellanos et al. (1980 ▶). The hydrogen-bonding ability of axial versus equatorial hydroxy groups is discussed by Bonnet et al. (2005 ▶), and further examples in related structures are provided by Neis, Merten & Hegetschweiler (2012 ▶) and Neis, Merten, Altenhofer & Hegetschweiler (2012 ▶). Puckering parameters have been calculated according to Cremer & Pople (1975 ▶). For the treatment of hydrogen atoms in SHELXL, see: Müller et al. (2006 ▶).