Research Article: Tris(cis-2-hy­droxy­cyclo­hexane-1,3,5-tri­aminium) hydrogen sulfate octa­chloride dihydrate

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.

Partial Text

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 ▶).




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