2-[(E)-2-(1H-Indol-3-yl)ethen­yl]-1-methyl­pyridinium 4-chloro­benzene­sulfonate

Thawanrat Kobkeatthawin; Suchada Chantrapromma; Hoong-Kun Fun

doi:10.1107/S1600536809029547

. 2009 Jul 31;65(Pt 8):o2045–o2046. doi: 10.1107/S1600536809029547

2-[(E)-2-(1H-Indol-3-yl)ethenyl]-1-methylpyridinium 4-chlorobenzenesulfonate¹

Thawanrat Kobkeatthawin ^a, Suchada Chantrapromma ^a,^*, Hoong-Kun Fun ^b,^‡

PMCID: PMC2977504 PMID: 21583709

Abstract

In the title compound, C₁₆H₁₅N₂ ⁺·C₆H₄ClO₃S⁻, the cation exists in an E configuration with respect to the central C=C bond and is approximately planar, with a dihedral angle of 2.95 (5)° between the pyridinium and indole rings. The mean plane of the π-conjugated system of the cation and the benzene ring of the anion are inclined to each other at a dihedral angle of 69.65 (4)°. In the crystal packing, the cations are stacked in an antiparallel manner along the a axis, resulting in a π–π interaction with a centroid–centroid distance of 3.5889 (7) Å. The anions are linked into a chain along the a axis by weak C—H⋯O interactions. The cations are linked with the anions into a three-dimensional network by N—H⋯O hydrogen bonds and weak C—H⋯O interactions. There are also short O⋯Cl [3.1272 (10) Å] and C⋯O [3.1432 (14)–3.3753 (14) Å] contacts. The crystal structure is further stabilized by C—H⋯π interactions.

Related literature

For bond-length data, see: Allen et al. (1987 ▶). For background to non-linear optical materials research, see: Ogawa et al. (2008 ▶); Weir et al. (2003 ▶); Yang et al. (2007 ▶). For related structures, see: Chanawanno et al. (2008 ▶); Chantrapromma et al. (2006 ▶, 2007 ▶, 2008 ▶, 2009 ▶). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986 ▶).

Experimental

Crystal data

C₁₆H₁₅N₂ ⁺·C₆H₄ClO₃S⁻
M _r = 426.91
Monoclinic,
a = 7.4891 (1) Å
b = 13.1650 (1) Å
c = 20.3428 (2) Å
β = 98.801 (1)°
V = 1982.06 (4) Å³
Z = 4
Mo Kα radiation
μ = 0.33 mm⁻¹
T = 100 K
0.34 × 0.28 × 0.19 mm

Data collection

Bruker APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T _min = 0.899, T _max = 0.942
39049 measured reflections
8706 independent reflections
7032 reflections with I > 2σ(I)
R _int = 0.034

Refinement

R[F ² > 2σ(F ²)] = 0.040
wR(F ²) = 0.110
S = 1.05
8706 reflections
267 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.88 e Å⁻³
Δρ_min = −0.41 e Å⁻³

Data collection: APEX2 (Bruker, 2005 ▶); cell refinement: SAINT (Bruker, 2005 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809029547/is2441sup1.cif

e-65-o2045-sup1.cif^{(22.4KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809029547/is2441Isup2.hkl

e-65-o2045-Isup2.hkl^{(425.9KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H1N2⋯O1ⁱ	0.891 (18)	1.864 (19)	2.7541 (14)	176.2 (18)
C1—H1A⋯O3	0.93	2.53	3.2380 (14)	133
C7—H7A⋯O2ⁱⁱ	0.93	2.59	3.3067 (14)	134
C14—H14A⋯O2ⁱⁱⁱ	0.93	2.52	3.2605 (14)	137
C16—H16C⋯O2ⁱⁱⁱ	0.96	2.37	3.2645 (15)	156
C19—H19A⋯O1^iv	0.93	2.30	3.1432 (14)	151
C21—H21A⋯O3ⁱⁱⁱ	0.93	2.55	3.1885 (14)	127
C4—H4A⋯Cg3^v	0.93	2.85	3.5956 (11)	138
C16—H16A⋯Cg1^vi	0.96	2.72	3.4622 (12)	134
C16—H16B⋯Cg3	0.96	2.67	3.5533 (11)	153

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) ; (v) ; (vi) . Cg1 and Cg3 are the centroids of the N2/C8–C9/C10/C15 and C10–C15 rings, respectively.

Acknowledgments

The authors thank the Prince of Songkla University for financial support through the Crystal Materials Research Unit. The authors also thank Universiti Sains Malaysia for the Research University Golden Goose grant No. 1001/PFIZIK/811012.

supplementary crystallographic information

Comment

Molecules with extensive conjugated π systems are attractive candidates for non-linear optical (NLO) studies (Ogawa et al., 2008; Weir et al., 2003; Yang et al., 2007). However a molecule with extensive conjugated π systems does not always exhibit second order NLO properties unless the alignment of these molecules is in a noncentrosymmetric space group in the crystal. In our NLO research we have solved a number of crystal structures of pyridinium salt derivatives (Chanawanno et al., 2008; Chantrapromma et al., 2006, 2007, 2008, 2009) which we attempt to examine in details of the relationship between their crystal packings and the NLO properties. We herein report the crystal structure of the title compound (I) which is iso-structure and iso-packing with 2-[(E)-2(1H-Indol-3-yl)ethenyl]-1-methylpyridinium 4-bromobenzenesulfonate (Chantrapromma et al., 2009).

Figure 1 shows the asymmetric unit of (I) which consists of a C₁₆H₁₅N₂⁺ cation and a C₆H₄ClO₃S^- anion. The cation exists in the E configuration with respect to the C6═C7 double bond [1.3567 (14) Å] and is essentially planar with the dihedral angle between the pyridinium and indole rings being 2.96 (5)° and the torsion angles C4–C5–C6–C7 = -1.21 (17)° and C6–C7–C8–C15 = -176.40 (11)°. The indole ring system is planar with the maximum deviation of 0.014 (1) Å for atom C8. The mean planes through π-conjugated systems of the cation and the anion are inclined to each other with an interplanar angle of 69.65 (4)°. The methyl group is co-planar with the attached N1/C1–C5 ring. The bond lengths in (I) are in normal ranges (Allen et al., 1987) and are comparable with those in related structures (Chanawanno et al., 2008; Chantrapromma et al., 2006, 2007, 2008, 2009).

In the crystal packing (Fig. 2), all O atoms of the sulfonate group are involved in weak C—H···O interactions (Table 1). The arrangement of the cations and anions is interesting (Fig. 2). The cations are stacked in an antiparallel manner along the a axis resulting in a π–π interaction with the distance Cg₁···Cg₂ = 3.5889 (7) Å (symmetry code: -x, -y, -z). The anions are linked together into chains by weak C—H···O interactions along the same direction. The cations are linked to the anions into a three dimensional network by N—H···O hydrogen bonds and weak C—H···O interactions (Table 1). There are O···Cl [3.1272 (10) Å] and C···O [3.1432 (14)–3.3753 (14) Å] short contacts. The crystal structure is further stabilized by C—H···π interactions (Table 1); Cg₁, Cg₂ and Cg₃ are the centroids of the N2/C8–C9/C10/C15, N1/C1–C5 and C10–C15 rings, respectively.

Experimental

The title compound was synthesized by disolving silver(I) p-chlorobenzenesulfonate (Chantrapromma et al., 2006) (0.20 g, 0.67 mmol) in methanol (20 ml) which upon heating was added a solution of 2-[(E)-2-(1H-Indol-3-yl)ethenyl]-1-methylpyridinium iodide (Chantrapromma et al., 2009) (0.24 g, 0.67 mmol) in hot methanol (30 ml). The mixture turned yellow and cloudy immediately. After stirring for 0.5 hr, the precipitate of silver iodide which formed was filtered and the filtrate was evaporated to give an orange gum. Yellow block-shaped single crystals of the title compound suitable for x-ray structure determination were recrystalized from methanol by slow evaporation of the solvent at room temperature after a few weeks (m.p. 457-459 K).