8-Hydroxyquinolin-1-ium hydrogen sulfate monohydrate

In the crystal structure of the title salt hydrate, C9H8NO+·HSO4 −·H2O, the quinoline N—H atoms are hydrogen bonded to the bisulfate anions. The bisulfate anions and water molecules are linked together by O—H⋯O hydrogen-bonding interactions. The cations and anions form separate layers alternating along the c axis, which are linked by N—H⋯O and O—H⋯O hydrogen bonds into a two-dimensional network parallel to (100). Further O—H⋯O contacts connect these layers, forming a three-dimensional network, in which two R 4 4(12) rings and C 2 2(13) infinite chains can be identified.


Related literature
Data collection: CrysAlis PRO (Agilent, 2011); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SIR2002 (Burla et al., 2003); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and DIAMOND (Brandenburg & Berndt, 2001); software used to prepare material for publication: WinGX (Farrugia, 2012). Recently, hydrogen-bonding patterns involving quinoline and its derivatives with organic acid have been investigated (Loh et al., 2010a,b). Syntheses of the quinoline derivatives were discussed earlier (Sasaki et al., 1998;Reux et al., 2009). Quinolines and their derivatives are very important compounds because of their wide occurrence in natural products (Morimoto et al., 1991) and biologically active compounds (Markees et al., 1970). Herein we report the synthesis and crystal structure of 8-hydroxy-quinolin-1-ium hydrogen sulfate monohydrate (I). The molecular structure of (I), and the atomic numbering used, is illustrated in Fig. 1. The asymmetric unit of (I) consists of consists of one 8-hydroxy-quinolin-1-ium cation, one hydrogen sulfate anion and one water molecule. One proton is transferred from the hydroxyl group of sulfuric acid to the atom N1 of 8-hydroxy-quinoline during the crystallization, resulting in the formation of salt. All bond distances and angles are within the ranges of accepted values (CSD, Allen, 2002).
In the crystal structure, cationic and anionic layers alternate along the c axis and are linked by intermolecular N-H···O and O-H···O hydrogen bonds resulting in a two-dimensional network parallel to (100) ( Table 1; Fig.2). Further O-H···O contacts connect these layers, forming a three-dimensional network in which R 4 4 (12) rings and C 2 2 (13) infinite chains are generated.
Perhaps the most interesting aspect of the structure results from the hydrogen bonding between the bisulfate anions and the solvent water molecule. This results in the formation of a ladder motif that runs parallel to the a axis (Fig. 3). Each bisulfate ion serves as a hydrogen bond donor to one water molecule and a hydrogen bond acceptor from a second water molecule forming the rails of the ladder, of form C 2 2 (6). The rungs are formed via a second water-donor/bisulfate acceptor pair, which generates rings within the ladder structure (two rungs and two rail sections in each ring), R 4 4 (12). There are two chemically different rings formed in this case since one involves rail sections with water molecules serving as the hydrogen bond donor and the other involves the bisulfate ion serving as the hydrogen bond donor.

Experimental
Single crystals of the compound C 9 H 7 NO + . HSO -4 . H 2 O were grown as follows: 1 mmol of the copper sulfate pentahydrate CuSO 4 . 5H 2 O; 1 mmol of 8-hydroxy-quinoline and 1 mmol of sulfuric acid H 2 SO 4 were mixed together in a minimum amount of distilled water. The clear solutions were stirred for 15 min and allowed to stand at room temperature. After a few days, Yellow crystals were formed. The product was filtered off, washed with a small amount of distilled water and was carefully isolated under polarizing microscope for analysis by X-ray diffraction.

Refinement
Hydrogen atoms were localized on Fourier maps but introduced in calculated positions and treated as riding on their U iso (H)=1.5U eq (O). Exept for H1W and H2W atoms of water molecule were located in difference Fourier maps and included in the subsequent refinement with U iso (H) = 1.5U eq (O).

Special details
Experimental. Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm. CrysAlisPro (Agilent Technologies, 2011) 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.