4-(4-Bromostyryl)-1-methylpyridinium tosylate

In the cation of the title compound, C14H13BrN+·C7H7O3S−, the dihedral angle between the benzene and pyridine rings is 8.34 (11)°. The Br atom is disordered over two positions with site occupancies of 0.74 (2) and 0.26 (2). The molecular structure is stabilized by a weak intramolecular C—H⋯O interactions. The crystal structure exhibits weak C—H⋯O and π–π [centroid–centroid distance = 3.7466 (17) Å] interactions, forming a three dimensional network.


Related literature
For molecular compounds with non-linear optical properties, see: Bosshard et al. (1995); Nalwa & Miyata (1997 Table 1 Hydrogen-bond geometry (Å , ). In continuation of our studies of molecular compounds with non linear optical properties which are used in optoelectronic and photonic devices (Bosshard et al., 1995;Nalwa & Miyata, 1997), we herewith report the crystal structure of the title compound (I) (Fig. 1).
The asymmetric unit of the title compound consists of C 14 H 13 BrN + cations and C 7 H 7 O 3 Sanios. The geometric parameters of the title compound are agree well with those of reported structures (Krishnakumar et al., 2012;Sivakumar et al., 2012;Okada et al., 1990). In the cation, the bromine atom is disordered over two positions, with the site occupancies of 0.74 (2) and 0.26 (2). The cation is planar [torision angle C4-C7=C8-C9 = 178.1 (3)°] about the double bond between the two rings in the cation. The dihedral angle between the benzene ring and pyridinium ring in the cation is 8.34 (11)°.
The molecular structure is stabilized by weak intramolecular C-H···O interactions. In the crystal structure, adjacent anions and cations are linked by weak C-H···O (Table 1

Experimental
The title compound was synthesized by the condensation of 4-methyl-N-methyl pyridinium tosylate, which was prepared from 4-picoline (4.65g, 5 mmol) and methyl p-toluenesulfonate (9.31g, 5 mmol), and 4-bromobenzaldehyde (9.24 g, 5 mmol) in the presence of piperidine. The single crystals suitable for X-ray diffraction were grown by slow evaporation method in room temperature.

Refinement
H atoms were positioned geometrically and refined using a riding model with C-H = 0.93 Å and U iso (H) = 1.2U eq (C) for aromatic C-H, C-H = 0.96 Å and U iso (H) = 1.5U eq (C) for CH 3 . The components of the anisotropic displacement parameters in the direction of C4 and C7 were restrained to be equal within an effective deviation of 0.001 using DELU command in SHELXL (Sheldrick, 2008). The disorder of the bromine ligand suggests also disorder of the aromatic ring to which it is attached, but no split model for this ring could be found.  The molecular structure of (I), with atom labels and 30% probability displacement ellipsoids for non-H atoms.

Figure 2
The packing of (I), viewed down b axis. Intermolecular Hydrogen bonds are shown as dashed lines. H atoms not involved in hydrogen bonding have been omitted. where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.34 e Å −3 Δρ min = −0.30 e Å −3 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.