Cyclooctanaminium hydrogen succinate monohydrate

In the title hydrated salt, C8H18N+·C4H5O4 −·H2O, the cyclooctyl ring of the cation is disordered over two positions in a 0.833 (3):0.167 (3) ratio. The structure contains various O—H.·O and N—H⋯O interactions, forming a hydrogen-bonded layer of molecules perpendicular to the c axis. In each layer, the ammonium cation hydrogen bonds to two hydrogen succinate anions and one water molecule. Each hydrogen succinate anion hydrogen bonds to neighbouring anions, forming a chain of molecules along the b axis. In addition, each hydrogen succinate anion hydrogen bonds to two water molecules and the ammonium cation.

In the title hydrated salt, C 8 H 18 N + ÁC 4 H 5 O 4 À ÁH 2 O, the cyclooctyl ring of the cation is disordered over two positions in a 0.833 (3):0.167 (3) ratio. The structure contains various O-H.ÁO and N-HÁ Á ÁO interactions, forming a hydrogen-bonded layer of molecules perpendicular to the c axis. In each layer, the ammonium cation hydrogen bonds to two hydrogen succinate anions and one water molecule. Each hydrogen succinate anion hydrogen bonds to neighbouring anions, forming a chain of molecules along the b axis. In addition, each hydrogen succinate anion hydrogen bonds to two water molecules and the ammonium cation.
The title compound ( Fig.1) crystallizes in Pbca and contains three independent molecules: a cyclooctanaminium cation disordered over two positions in a 0833 (3):0.167 (3) ratio, a hydrogen succinate anion, and a water molecule (Scheme 1).
The crystal structure consists of a hydrogen bonded layer composed of several different hydrogen bonds between the three molecules (Fig. 2). The hydrogen succinate anions are linked via an intermolecular O3-H3···O1 hydrogen bond to form chains of molecules along the b axis described by the graph set C7 (Fig. 3) (Etter et al., 1990;Bernstein et al., 1995). All three independent molecules are linked via hydrogen bonding to form a ring described by the graph set motif R 3 5 (12). The three ammonium hydrogen atoms are involved in strong hydrogen bonds with the O atoms of the neighbouring succinate anions (N-H1C···O1 and N-H1A···O2) and a hydrogen bond with the water molecule (N-H1B···O1W). The water molecule act as both hydrogen acceptor (accepts the H atom from N) and donor (donates H atoms to the succinate anions) to surrounding molecules. The combination of these hydrogen bonds leads to a twodimensional hydrogen bonded layer of molecules perpedicular to the c axis. A list hydrogen bonding interactions are given in Table 1.

Experimental
The title compound was obtained after a failed synthesis. Succinic acid [succinic anhydride having reacted with water in the reagent bottle over time (years)] was dissolved in dioxane followed by the addition of an equimolar amount of cyclooctylamine. After 6 h, thionyl chloride in dioxane was slowly added to the reaction mixture at room temperature. The mixture was then kept at 50 °C for 6 h, followed by neutralization of excess thionyl chloride by pouring the mixture into a beaker containing ice. The mixture was then filtered and the solvent removed under reduced pressure. This was then redissolved in methanol which after a few days of evaporation yielded crystals suitable for analysis by X-ray diffraction.

Refinement
H atoms in the cation and anion were positioned geometrically, and allowed to ride on their parent atoms, with Atom-H bond lengths of 0.99 Å (CH 2 ), or 0.91 Å (NH 3 ), or 0.84 Å (COOH), and isotropic displacement parameters set to 1.2 times (CH 2 ) or 1.5 times (NH 3 and COOH) the U eq of the parent atom. Hydrogen atoms of the water molecule were supplementary materials sup-2 Acta Cryst. (2012). E68, o1204 refined freely.

Figure 1
The asymmetric unit of (I). Only the major disorder component of the cation is shown.   Hydrogen bonded chains of hydrogen succinate anions in the structure of (I). Also shown are the hydrogen bonding environments around the ammonium cations and the water molecules. Hydrogen bonds are drawn as dashed lines.

Special details
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.