1-Hydroxyisoquinolin-2-ium hydrogen succinate

In the title salt, C9H8NO+·C4H5O4 −, the isoquinolinium ring system is approximately planar [r.m.s deviation = 0.011 (2) Å]. In the crystal, adjacent cations and anions are linked by O—H⋯O and N—H⋯O hydrogen bonds, forming columns along the b axis. The columns are connected by weak C—H⋯O interactions into a three-dimensional network.

In the title salt, C 9 H 8 NO + ÁC 4 H 5 O 4 À , the isoquinolinium ring system is approximately planar [r.m.s deviation = 0.011 (2) Å ]. In the crystal, adjacent cations and anions are linked by O-HÁ Á ÁO and N-HÁ Á ÁO hydrogen bonds, forming columns along the b axis. The columns are connected by weak C-HÁ Á ÁO interactions into a three-dimensional network.
Experimental Crystal data

Comment
Quinolinium derivatives are known to exhibit interesting bioactivities and pharmacological activities (Hopkins et al., 2005;Musiol et al., 2006). We herewith report the crystal structure of the title compound (Fig. 1). The bond lengths of the anion are within normal range (Allen et al., 1987) and the bond lengths of cation are comparable with the reported similar structure (Loh et al., 2010).

Experimental
1-Hydroxyisoquinolin-2-ium succinate was synthesized using the raw materials 1-hydroxyisoquinoline (1.45 g) and succinic acid (1.18 g) in an equimolar ratio. These reactants were dissolved in 10 ml of ethanol solvent and yellow precipitate was obtained after some time. The precipitate was dissolved in the same solvent and it is kept at room temperature for crystallization. After a span of four days, rod like crystals for diffraction study were harvested.

Refinement
H atoms for C aromatic H and CH 2 were positioned geometrically and refined using riding model, with C-H = 0.93 and 0.97 Å, respectively, and with U iso (H) = 1.2U eq (C). H atoms bounded to N and O atoms were located in a difference Fourier map and refined with U iso (H) = 1.5U eq (N, O) and distance restraints of O-H = 0.82 (1) Å and N-H = 0.86 (1) Å. One reflection (0 0 1) was omited during refinement as it was showing poor agreement.  The molecular structure of the title cpompound, with atom labels and 30% probability displacement ellipsoids for non-H atoms.

Figure 2
The packing diagram of the title compound, viewed down the b axis. Intermolecular hydrogen bonds are shown as dashed lines. H atoms not involved in hydrogen bonding have been omitted. 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.