Hydrogen-bonding patterns in cis-4-ammoniocyclohexanecarboxylate hemihydrate
Abstract:In the title compound, C7H13NO2·0.5H2O, cis-4-aminocyclohexanecarboxylic acid exists as a zwitterion and co-crystallizes with water molecules in a 2:1 amino acid–water ratio. The cyclohexane ring adopts a chair conformation, with the carboxylate and ammonium groups in axial and equatorial positions, respectively. The basic motif in the crystal structure is a sandwich structure, formed by two amino acid units linked by head-to-tail hydrogen bonds. Hydrogen bonds of the type N+—H…O—C—O− link these motifs, forming helicoidally extended chains running along the c axis. The water molecule lies on a twofold axis and interacts with the chains by means of O—H…O hydrogen bonds.
Document Type: Research Article
Publication date: 2004-10-01