Determination of the crystal structures of the homologous (1R*,2R*)-trans-2-hydroxy-1-cyclopentanecarboxylic acid (5T), (1R*,2S*)-cis-2-hydroxy-1-cyclohexanecarboxylic acid (6C) and (1R*,2S*)-cis-2-hydroxy-1-cycloheptanecarboxylic acid (7C) proved a predicted pattern of supramolecular close packing. The prediction was based on the common features observed in the crystal structures of six related 2-hydroxy-1-cyclopentanecarboxylic acids and analogous carboxamides [Kálmán et al. (2001). Acta Cryst. B57, 539-550]. This pattern is characterized by tetrameric R44(12) rings of C2 symmetry formed from dimeric R22(12) rings. The C2 symmetry of such tetramers is not common in the literature, usually they have Ci symmetry. Both types of tetramers are formed from dimers with similar or opposite orientation. The R22(12) dimers differ in their hydrogen bonds. In 5T the monomers are joined by a pair of O1-H⋯-O2=C bonds, whereas in 7C they are joined by a pair of O3-H⋯O1-H bonds. In 6C 60% of the disordered R22(12) dimers are similar to those in 7C, while 40% resemble those in 5T. Apart from these hydrogen-bonding differences and the ring-size differences, the three crystals exhibit isostructurality.
|Number of pages||8|
|Journal||Acta Crystallographica Section B: Structural Science|
|Issue number||3 PART 2|
|Publication status||Published - Jun 1 2002|
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)