(E)-2-[4-(Dimethyl­amino)­styr­yl]-1-methyl­pyridinium triiodide

Hoong-Kun Fun; Kullapa Chanawanno; Suchada Chantrapromma

doi:10.1107/S1600536811028753

. 2011 Jul 30;67(Pt 8):o2151. doi: 10.1107/S1600536811028753

(E)-2-[4-(Dimethylamino)styryl]-1-methylpyridinium triiodide

Hoong-Kun Fun ^a,^*,^‡, Kullapa Chanawanno ^b, Suchada Chantrapromma ^b,^§

PMCID: PMC3213589 PMID: 22091166

Abstract

The asymmetric unit of the title compound, C₁₆H₁₉N₂ ⁺·I₃ ⁻, contains a (E)-2-[4-(dimethylamino)styryl)-1-methylpyridinium cation and half each of two triiodide anions. The complete triiodide anions are each generated by inversion symmetry. The planar cation has all of its eighteen non-H atoms situated on a mirror plane. In the crystal, the cations are stacked along the b axis by π–π interactions with a centroid–centroid distance of 3.5757 (13) Å. The triiodide anions are located between the cations. The crystal structure is further consolidated by short C⋯C [3.322 (9)–3.3952 (19) Å] contacts.

Related literature

For background to and applications of pyridinium compounds, see: Chanawanno et al. (2010 ▶); Fisicaro et al. (1990 ▶); Pernak et al. (2001 ▶). For related structures, see: Chantrapromma et al. (2010 ▶); Zhang et al. (2008 ▶). For standard bond lengths, see: Allen et al. (1987 ▶). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986 ▶).

Experimental

Crystal data

C₁₆H₁₉N₂ ⁺·I₃ ⁻
M _r = 620.03
Monoclinic,
a = 19.8760 (3) Å
b = 6.6126 (1) Å
c = 14.4421 (2) Å
β = 95.107 (1)°
V = 1890.62 (5) Å³
Z = 4
Mo Kα radiation
μ = 4.96 mm⁻¹
T = 100 K
0.45 × 0.15 × 0.04 mm

Data collection

Bruker APEX DUO CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009 ▶) T _min = 0.212, T _max = 0.838
16143 measured reflections
2484 independent reflections
2263 reflections with I > 2σ(I)
R _int = 0.030

Refinement

R[F ² > 2σ(F ²)] = 0.030
wR(F ²) = 0.079
S = 1.04
2484 reflections
129 parameters
H-atom parameters constrained
Δρ_max = 1.74 e Å⁻³
Δρ_min = −0.60 e Å⁻³

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: SAINT (Bruker, 2009 ▶); 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 datablock(s) global, I. DOI: 10.1107/S1600536811028753/sj5182sup1.cif

e-67-o2151-sup1.cif^{(17.8KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811028753/sj5182Isup2.hkl

e-67-o2151-Isup2.hkl^{(122.1KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536811028753/sj5182Isup3.cml

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

Acknowledgments

Financial support by the Prince of Songkla University is greatfully acknowledged. The authors also thank Universiti Sains Malaysia for the Research University Grant No. 1001/PFIZIK/811160. KC thanks the Crystal Materials Research Unit for the Research Assistance fellowship.

supplementary crystallographic information

Comment

Pyridinium halide salts, generally possess surface active and interesting antimicrobial properties. They contain reactive functional groups covalently bound to the long hydrophobic chain and can exhibit biological activity (Fisicaro et al., 1990; Chanawanno et al., 2010). It has been proven that one of the factors which control their antimicrobial activity is the presence of anions in the compounds. In the work done by Pernak and coworkers, it was shown that the various anion types can exhibit different antimicrobial activities (Pernak et al., 2001). As our ongoing research is aimed at enhancing the antimicrobial activity of pyridinium salts, we have synthesized pyridinium salts with various anions in order to investigate the relationship between the types of anion and their antimicrobial properties. In the course of this work, the title compound (I) was synthesized and its crystal structure is reported here.

Fig. 1 shows the molecular structure of the title compound (I); the asymmetric unit consists of a C₁₆H₁₉N₂⁺ cation and two half-I₃^- anions. The complete molecule of one triiodide anion (I2A) is generated by a crystallographic symmetry centre 1 - x, y, -z whereas the other (I4A) is by 1 - x, y, 1 - z. The cation is 100% planar as all its eighteen non-hydrogen atoms lie on a mirror plane, x, 0, z. One H atom of each of its three methyl groups at C14, C15 and C16 also lies in the mirror plane. The cation exists in an E configuration with respect to the C6═C7 double bond [1.327 (8) Å] and the torsion angles C5–C6–C7–C8 = 180.000 (3)°. The bond lengths (Allen et al., 1987) and angles in (I) are in normal ranges and comparable to those found in related structures (Chantrapromma et al., 2010; Zhang et al., 2008).

In the crystal packing (Fig. 2) the cations are stacked along the b axis by π···π interactions with the distances Cg₁···Cg₂ = 3.5757 (13) Å (symmetry codes: 1/2 - x, -1/2 + y, 2 - z; 1/2 - x, 1/2 + y, 2 - z; 1/2 - x, -1/2 - y, 2 - z and 1/2 - x, 1/2 - y, 2 - z); Cg₁ and Cg₂ are the centroids of the C1–C5/N1 and C8–C13, respectively. Triiodide anions are located in the interstitials of the cations. The crystal structure is further consolidated by these π···π interactions and short C···C [3.322 (9)–3.3952 (19)Å] contacts.

Experimental

The title compound was synthesized by mixing a solution of (E)-2-[4-(dimethylamino)styryl]-1-methylpyridinium iodide (Zhang et al., 2008) (0.20 g, 0.55 mmol) in hot methanol (50 ml) and a solution of CuI₂ (0.17 g, 0.55 mmol) in hot methanol (30 ml). The mixture was stirred for half an hour and then left at room temperature. The title compound was formed as a red solid after 2 days. Orange needle-shaped single crystals suitable for x-ray structure determination were obtained by recrystallization from ethanol by slow evaporation of the solvent at ambient temperature over several days, M.p. >573 K.