1-(2,3-Dicyanophenyl)pyridin-1-ium-4-olate monohydrate

In the crystal structure of the title compound, C13H7N3O·H2O, the components are associated into chains along [010] through strong O—H⋯O hydrogen bonds with the free water molecules as bridging ligands. These chains are further cross-linked by C—H⋯O and C—H⋯N hydrogen bonds, forming a three-dimensional structure.

In the crystal structure of the title compound, C 13 H 7 N 3 OÁH 2 O, the components are associated into chains along [010] through strong O-HÁ Á ÁO hydrogen bonds with the free water molecules as bridging ligands. These chains are further cross-linked by C-HÁ Á ÁO and C-HÁ Á ÁN hydrogen bonds, forming a three-dimensional structure.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: BV2216).

Experimental
The preparation of the title compound, see, Archibald et al. (1994)

Refinement
All hydrogen atoms bound to carbon were refined using a riding model with distance C-H = 0.93 Å, U iso = 1.2U eq (C) for aromatic atoms. The H atoms of the water molecule were located from difference density maps and were refined isotrpically.

Figure 1
The asymmetric unit of the title compound with the atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level; H atoms are given as spheres of arbitrary radius.  The packing diagram of the title compound with hydrogen bonds shown as dashed lines.

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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.