8-Hydroxy-5-(hydroxymethyl)quinolin-1-ium chloride

The title compound, C10H10NO2 +·Cl−, contains a quinoline ring system which is essentially planar, with the largest deviation from the mean plane being 0.017 (1) Å. In the crystal, the ion pairs and their inversion-symmetry-related partners are linked by N—H⋯Cl and O—H⋯Cl hydrogen bonds to form tetramers which are further connected through O—H⋯O hydrogen bonds, building infinite one-dimensional chains parallel to the [010] direction.

The 5-(hydroxymethyl)-8-quinolinol hydrochloride molecule structure is built up from two fused six-membered rings linked to CH 2 OH and to OH groups as shown in Fg.1. The fused-ring system is essentially planar, with the maximum deviation of 0.017 (1) Å from C7 atom. The dihedral angle between them does not exceed 1.15 (5) (Table 1).
Experimental 5-Chloromethyl-8-hydroxyquinoline hydrochloride (I) was synthesized according to the method described by Zheng et al. (2005). A mixture of 10.0 g (0.068 mol) of 8-hydroxyquinoline, 11 ml of concentrated hydrochloric acid, and 11 ml (0.397 mol) of 37% formaldehyde was treated with hydrogen chloride gas and stirred for 6 h. The solution was allowed to stand at room temperature for 2 h without stirring. The yellow solid obtained was collected on a filter, washed with acetone or alcohol, and dried under vacuum to give 5-chloromethyl-8-hydroxyquinoline hydrochloride (I) (13.0 g, 98%).
The compound obtained was dissolved in distilled water in a box Petrys and let in air at room temperature. After 10 days, transparent single crystals as platelets were isolated. X-ray diffraction analysis shows that the obtained product is the 5-(hydroxymethyl)-8-quinolinol hydrochloride.

Figure 1
Molecular structure of the title compound with the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms are represented as small circles.

Figure 2
Molecule and its symmetry through the inversion center linked by hydrogen bonds and building dimers. where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.001 Δρ max = 0.50 e Å −3 Δρ min = −0.20 e Å −3 Special details Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq