1-Methyl-2-[(E)-2,4,5-trimethoxystyryl]pyridinium 4-methoxybenzenesulfonate monohydrate

In the title compound, C17H20NO3 +·C7H7O4S−·H2O, the cation exists in an E configuration with respect to the C=C bond and is twisted with a dihedral angle of 17.81 (8)° between the pyridinium and benzene rings. The benzene ring of the anion is almost parallel to the pyridinium ring [dihedral angle = 3.45 (9)°], whereas it is inclined to the benzene ring of the cation [dihedral angle = 17.62 (8)°]. The crystal structure is stabilized by O—H⋯O hydrogen bonds and weak C—H⋯O interactions which link the cations, anions and water molecules into chains along the a axis. π–π interactions with centroid–centroid distances of 3.7751 (9) and 3.7920 (11) Å are also observed.


Comment
Within the frame of our on-going research on non-linear optic (NLO) materials and antibacterial compounds, we have synthesized several pyridinium and quinolinium derivatives, and their NLO properties and antibacterial activities have been reported Chantrapromma et al., 2007;Fun et al., 2009;Ruanwas et al., 2010). As part of this research the title pyridinium derivative, (I), was synthesized and its crystal structure is herein reported. The title compound crystallizes in the centrosymmetric triclinic P1 space group and therefore it does not exhibit second order NLO properties (Williams, 1984). In addition, (I) was also tested for antibacterial activities against Bacillus subtilis, Enterococcus faecalis, Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus faecalis, Pseudomonas aeruginosa, Salmonella typhi and Shigella sonnei, and it was found to be inactive. the methoxy group is co-planar with the benzene ring forming a torsion angle C24-O7-C23-C18 = 1.2 (2)°. The benzene ring of the anion is almost parallel to the pyridinium ring (dihedral angle 3.45 (9)°), whereas it is inclined to the benzene ring of the cation at 17.62 (8)°. The bond lengths of (I) are in normal ranges (Allen et al., 1987) and comparable to those found in related structures Mueangkeaw et al., 2010).
In the crystal packing, the cations are linked to both anions and water molecules by weak C-H···O interactions, and the anions are linked to water molecules by O-H···O hydrogen bonds to form chains along the a axis (Table 1, Fig. 2).
Experimental 1-Methyl-2-[(E)-2,4,5-trimethoxystyryl]pyridinium iodide (compound A) was prepared according to the previously reported method (Mueangkeaw et al.,2010). Silver(I) 4-methoxybenzenesulfonate (compound B) was synthesized by following the previous procedure (Chantrapromma et al.,2007). The title compound was prepared by mixing a 1:1 molar ratio of compound A (0.100 g, 0.24 mmol) and compound B (0.071 g, 0.24 mmol) in hot CH 3 OH (50 ml). The mixture immediately yielded a grey precipitate of silver iodide. After stirring the mixture for ca. 30 min, the precipitate was removed and the resulting solution was evaporated yielding an orange viscous oil. Orange needle-shaped single crystals of the title compound suitable sup-2 for x-ray structure determination were recrystallized from DMSO by slow evaporation at room temperature over a few weeks, M.p. 453-454 K.

Refinement
Water H atoms were located in difference maps and refined isotropically. The remaining H atoms were positioned geometrically and allowed to ride on their parent atoms, with d(C-H) = 0.93 Å for aromatic and CH and 0.96 Å for CH 3 atoms. The U iso values were constrained to be 1.5U eq of the carrier atom for methyl H atoms and 1.2U eq for the remaining H atoms. A rotating group model was used for the methyl groups. The highest residual electron density peak is located at 0.75 Å from O6 and the deepest hole is located at 0.75 Å from S1.
Figures Fig. 1. The asymmetric unit of the title compound, with 50% probability displacement ellipsoids.

Special details
Experimental. The crystal was placed in the cold stream of an Oxford Cryosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) K.
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. supplementary materials sup-9