organic compounds
2-[(E)-4-(Diethylamino)styryl]-1-methylpyridinium iodide
aCrystal Materials Research Unit, Department of Chemistry, Faculty of Science, Prince of Songkla University, Hat-Yai, Songkhla 90112, Thailand, and bX-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia
*Correspondence e-mail: suchada.c@psu.ac.th
In the title compound, C18H23N2+·I−, the cation exists in the E configuration with respect to the ethenyl C=C bond. The pyridinium and benzene rings are nearly coplanar, making a dihedral angle of 4.63 (7)°. The two ethyl groups of the diethylamino substituent point in opposite directions with respect to the benzene plane. In the crystal, the cation and the iodide anion are linked by a weak C—H⋯I interaction. The cations are stacked in an anti-parallel manner along the a axis by a π–π interaction with a centroid–centroid distance of 3.5262 (9) Å. The is further stabilized by C—H⋯π interactions.
Related literature
For bond-length data, see: Allen et al. (1987). For background to styryl pyridinium see: Browning et al. (1922, 1923); Chanawanno et al. (2010); Wainwright & Kristiansen (2003). For related structures, see: Chanawanno et al. (2008); Fun et al. (2009). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986).
Experimental
Crystal data
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Refinement
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Data collection: APEX2 (Bruker, 2005); cell 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).
Supporting information
10.1107/S1600536810037505/is2599sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536810037505/is2599Isup2.hkl
The title compound (I) was prepared by mixing 1:1:1 molar ratio solutions of 1,2-dimethylpyridinium iodide (2 g, 8.5 mmol), 4-diethylaminobenzaldehyde (1.52 ml, 8.5 mmol) and piperidine (0.84 ml, 8.5 mmol) in methanol (40 ml). The resulting solution was refluxed for 6 hours under a nitrogen atmosphere. The orange solid which formed was filtered and washed with diethylether. Orange block-shaped single crystals of (I) suitable for x-ray
were recrystallized from methanol by slow evaporation at room temperature over a few weeks (m.p. 527-529 K).All H atoms were located in a difference map and refined isotropically. The highest residual electron density peak is located at 1.57 Å from I1 and the deepest hole is located at 0.48 Å from I1.
Data collection: APEX2 (Bruker, 2005); cell
SAINT (Bruker, 2005); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).C18H23N2+·I− | F(000) = 792 |
Mr = 394.28 | Dx = 1.533 Mg m−3 |
Monoclinic, P21/c | Melting point = 527–529 K |
Hall symbol: -P 2ybc | Mo Kα radiation, λ = 0.71073 Å |
a = 7.7099 (1) Å | Cell parameters from 6198 reflections |
b = 20.2780 (4) Å | θ = 2.0–32.6° |
c = 10.9375 (2) Å | µ = 1.87 mm−1 |
β = 92.527 (1)° | T = 100 K |
V = 1708.32 (5) Å3 | Block, orange |
Z = 4 | 0.34 × 0.30 × 0.21 mm |
Bruker APEXII CCD area detector diffractometer | 6198 independent reflections |
Radiation source: sealed tube | 5765 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.026 |
ϕ and ω scans | θmax = 32.6°, θmin = 2.0° |
Absorption correction: multi-scan (SADABS; Bruker, 2005) | h = −8→11 |
Tmin = 0.570, Tmax = 0.691 | k = −29→30 |
23707 measured reflections | l = −16→16 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.022 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.070 | All H-atom parameters refined |
S = 1.10 | w = 1/[σ2(Fo2) + (0.0312P)2 + 1.8072P] where P = (Fo2 + 2Fc2)/3 |
6198 reflections | (Δ/σ)max = 0.001 |
282 parameters | Δρmax = 0.51 e Å−3 |
0 restraints | Δρmin = −0.63 e Å−3 |
C18H23N2+·I− | V = 1708.32 (5) Å3 |
Mr = 394.28 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 7.7099 (1) Å | µ = 1.87 mm−1 |
b = 20.2780 (4) Å | T = 100 K |
c = 10.9375 (2) Å | 0.34 × 0.30 × 0.21 mm |
β = 92.527 (1)° |
Bruker APEXII CCD area detector diffractometer | 6198 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2005) | 5765 reflections with I > 2σ(I) |
Tmin = 0.570, Tmax = 0.691 | Rint = 0.026 |
23707 measured reflections |
R[F2 > 2σ(F2)] = 0.022 | 0 restraints |
wR(F2) = 0.070 | All H-atom parameters refined |
S = 1.10 | Δρmax = 0.51 e Å−3 |
6198 reflections | Δρmin = −0.63 e Å−3 |
282 parameters |
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 F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > 2sigma(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger. |
x | y | z | Uiso*/Ueq | ||
I1 | 0.385998 (14) | 0.649927 (5) | 0.254076 (9) | 0.01744 (4) | |
N1 | 0.27082 (18) | 0.63425 (7) | 0.69740 (12) | 0.0128 (2) | |
N2 | 0.1456 (2) | 0.33502 (7) | 0.09996 (13) | 0.0165 (3) | |
C1 | 0.3117 (2) | 0.66702 (9) | 0.80338 (15) | 0.0156 (3) | |
C2 | 0.3971 (2) | 0.63637 (9) | 0.89989 (15) | 0.0169 (3) | |
C3 | 0.4439 (2) | 0.57021 (9) | 0.88598 (15) | 0.0181 (3) | |
C4 | 0.4023 (2) | 0.53711 (8) | 0.77893 (15) | 0.0159 (3) | |
C5 | 0.3120 (2) | 0.56923 (8) | 0.68124 (14) | 0.0130 (3) | |
C6 | 0.2616 (2) | 0.53758 (8) | 0.56679 (15) | 0.0149 (3) | |
C7 | 0.3027 (2) | 0.47469 (8) | 0.53980 (14) | 0.0141 (3) | |
C8 | 0.2575 (2) | 0.44086 (8) | 0.42673 (14) | 0.0136 (3) | |
C9 | 0.1595 (2) | 0.46906 (8) | 0.32844 (15) | 0.0144 (3) | |
C10 | 0.1223 (2) | 0.43480 (8) | 0.22166 (15) | 0.0150 (3) | |
C11 | 0.1815 (2) | 0.36902 (8) | 0.20590 (14) | 0.0135 (3) | |
C12 | 0.2802 (2) | 0.34044 (8) | 0.30475 (15) | 0.0131 (3) | |
C13 | 0.3169 (2) | 0.37578 (8) | 0.41093 (14) | 0.0133 (3) | |
C14 | 0.0388 (2) | 0.36290 (9) | −0.00116 (15) | 0.0173 (3) | |
C15 | 0.1390 (3) | 0.40606 (10) | −0.08716 (17) | 0.0216 (3) | |
C16 | 0.2067 (2) | 0.26717 (8) | 0.08518 (15) | 0.0164 (3) | |
C17 | 0.0948 (3) | 0.21691 (9) | 0.14881 (17) | 0.0201 (3) | |
C18 | 0.1817 (2) | 0.67224 (9) | 0.59821 (16) | 0.0182 (3) | |
H1A | 0.285 (3) | 0.7107 (13) | 0.805 (2) | 0.020 (6)* | |
H2A | 0.426 (4) | 0.6591 (13) | 0.971 (3) | 0.029 (7)* | |
H3A | 0.512 (4) | 0.5499 (14) | 0.954 (3) | 0.031 (7)* | |
H4A | 0.434 (3) | 0.4942 (13) | 0.774 (2) | 0.019 (6)* | |
H6A | 0.198 (3) | 0.5628 (12) | 0.507 (2) | 0.014 (5)* | |
H7A | 0.369 (3) | 0.4489 (13) | 0.598 (2) | 0.020 (6)* | |
H9A | 0.120 (3) | 0.5160 (13) | 0.332 (2) | 0.021 (6)* | |
H10A | 0.055 (4) | 0.4541 (14) | 0.158 (3) | 0.027 (7)* | |
H12A | 0.325 (3) | 0.2966 (13) | 0.298 (2) | 0.020 (6)* | |
H14A | −0.057 (3) | 0.3869 (13) | 0.030 (2) | 0.017 (6)* | |
H13A | 0.384 (3) | 0.3571 (11) | 0.476 (2) | 0.015 (6)* | |
H14B | −0.013 (3) | 0.3265 (13) | −0.047 (2) | 0.021 (6)* | |
H15A | 0.061 (4) | 0.4195 (15) | −0.156 (3) | 0.037 (8)* | |
H15B | 0.238 (4) | 0.3824 (14) | −0.117 (2) | 0.026 (7)* | |
H15C | 0.180 (4) | 0.4425 (15) | −0.047 (3) | 0.028 (7)* | |
H16A | 0.323 (3) | 0.2637 (13) | 0.115 (2) | 0.022 (6)* | |
H16B | 0.202 (3) | 0.2567 (13) | 0.002 (2) | 0.020 (6)* | |
H17A | 0.139 (4) | 0.1730 (15) | 0.135 (3) | 0.029 (7)* | |
H17B | 0.098 (3) | 0.2228 (14) | 0.236 (2) | 0.021 (6)* | |
H17C | −0.022 (4) | 0.2207 (14) | 0.121 (2) | 0.027 (7)* | |
H18A | 0.176 (4) | 0.7175 (14) | 0.623 (2) | 0.027 (7)* | |
H18B | 0.069 (4) | 0.6552 (14) | 0.586 (3) | 0.032 (8)* | |
H18C | 0.244 (4) | 0.6682 (14) | 0.525 (3) | 0.023 (6)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
I1 | 0.02091 (6) | 0.01714 (6) | 0.01425 (6) | 0.00473 (4) | 0.00049 (4) | 0.00028 (3) |
N1 | 0.0135 (6) | 0.0121 (6) | 0.0130 (5) | 0.0000 (4) | 0.0022 (4) | 0.0001 (4) |
N2 | 0.0239 (7) | 0.0128 (6) | 0.0126 (6) | 0.0009 (5) | −0.0015 (5) | −0.0015 (5) |
C1 | 0.0179 (7) | 0.0143 (7) | 0.0147 (6) | −0.0003 (5) | 0.0036 (5) | −0.0022 (5) |
C2 | 0.0183 (7) | 0.0200 (7) | 0.0126 (6) | −0.0052 (6) | 0.0026 (5) | −0.0017 (5) |
C3 | 0.0205 (7) | 0.0187 (7) | 0.0149 (6) | −0.0030 (6) | −0.0018 (5) | 0.0035 (6) |
C4 | 0.0196 (7) | 0.0125 (7) | 0.0154 (6) | −0.0013 (5) | −0.0016 (5) | 0.0020 (5) |
C5 | 0.0121 (6) | 0.0129 (6) | 0.0140 (6) | −0.0011 (5) | 0.0019 (5) | −0.0003 (5) |
C6 | 0.0161 (7) | 0.0143 (7) | 0.0142 (6) | 0.0000 (5) | −0.0013 (5) | −0.0013 (5) |
C7 | 0.0142 (6) | 0.0140 (7) | 0.0141 (6) | −0.0010 (5) | 0.0006 (5) | −0.0007 (5) |
C8 | 0.0144 (6) | 0.0128 (6) | 0.0136 (6) | 0.0001 (5) | 0.0013 (5) | −0.0011 (5) |
C9 | 0.0143 (6) | 0.0128 (6) | 0.0160 (6) | 0.0015 (5) | 0.0014 (5) | −0.0003 (5) |
C10 | 0.0168 (7) | 0.0137 (7) | 0.0146 (6) | 0.0021 (5) | −0.0005 (5) | 0.0014 (5) |
C11 | 0.0150 (6) | 0.0128 (6) | 0.0127 (6) | −0.0012 (5) | 0.0011 (5) | −0.0010 (5) |
C12 | 0.0134 (6) | 0.0122 (6) | 0.0140 (6) | −0.0014 (5) | 0.0016 (5) | 0.0012 (5) |
C13 | 0.0136 (6) | 0.0126 (6) | 0.0138 (6) | 0.0009 (5) | 0.0011 (5) | 0.0003 (5) |
C14 | 0.0184 (7) | 0.0195 (7) | 0.0137 (6) | −0.0006 (6) | −0.0029 (5) | −0.0005 (6) |
C15 | 0.0229 (8) | 0.0255 (9) | 0.0166 (7) | 0.0000 (7) | 0.0018 (6) | 0.0029 (6) |
C16 | 0.0208 (7) | 0.0134 (7) | 0.0150 (6) | 0.0005 (6) | 0.0019 (5) | −0.0033 (5) |
C17 | 0.0229 (8) | 0.0172 (8) | 0.0205 (7) | −0.0029 (6) | 0.0025 (6) | −0.0042 (6) |
C18 | 0.0213 (8) | 0.0171 (7) | 0.0161 (7) | 0.0037 (6) | −0.0008 (6) | 0.0014 (6) |
N1—C1 | 1.361 (2) | C9—H9A | 1.00 (3) |
N1—C5 | 1.369 (2) | C10—C11 | 1.423 (2) |
N1—C18 | 1.475 (2) | C10—H10A | 0.93 (3) |
N2—C11 | 1.366 (2) | C11—C12 | 1.418 (2) |
N2—C14 | 1.463 (2) | C12—C13 | 1.383 (2) |
N2—C16 | 1.466 (2) | C12—H12A | 0.96 (3) |
C1—C2 | 1.368 (2) | C13—H13A | 0.94 (2) |
C1—H1A | 0.91 (3) | C14—C15 | 1.521 (3) |
C2—C3 | 1.399 (3) | C14—H14A | 0.96 (3) |
C2—H2A | 0.92 (3) | C14—H14B | 0.97 (3) |
C3—C4 | 1.375 (2) | C15—H15A | 0.99 (3) |
C3—H3A | 0.98 (3) | C15—H15B | 0.97 (3) |
C4—C5 | 1.409 (2) | C15—H15C | 0.91 (3) |
C4—H4A | 0.91 (3) | C16—C17 | 1.523 (3) |
C5—C6 | 1.445 (2) | C16—H16A | 0.94 (3) |
C6—C7 | 1.350 (2) | C16—H16B | 0.94 (2) |
C6—H6A | 0.95 (2) | C17—H17A | 0.97 (3) |
C7—C8 | 1.443 (2) | C17—H17B | 0.96 (2) |
C7—H7A | 0.95 (3) | C17—H17C | 0.94 (3) |
C8—C9 | 1.408 (2) | C18—H18A | 0.96 (3) |
C8—C13 | 1.410 (2) | C18—H18B | 0.94 (3) |
C9—C10 | 1.378 (2) | C18—H18C | 0.95 (3) |
C1—N1—C5 | 122.25 (14) | C12—C11—C10 | 117.06 (14) |
C1—N1—C18 | 117.02 (14) | C13—C12—C11 | 120.75 (15) |
C5—N1—C18 | 120.72 (14) | C13—C12—H12A | 119.0 (15) |
C11—N2—C14 | 122.16 (15) | C11—C12—H12A | 120.2 (15) |
C11—N2—C16 | 120.88 (14) | C12—C13—C8 | 122.16 (14) |
C14—N2—C16 | 116.90 (13) | C12—C13—H13A | 120.7 (15) |
N1—C1—C2 | 121.39 (16) | C8—C13—H13A | 117.1 (15) |
N1—C1—H1A | 116.3 (16) | N2—C14—C15 | 113.93 (15) |
C2—C1—H1A | 122.2 (16) | N2—C14—H14A | 110.1 (15) |
C1—C2—C3 | 117.98 (15) | C15—C14—H14A | 110.4 (15) |
C1—C2—H2A | 120.7 (18) | N2—C14—H14B | 107.8 (16) |
C3—C2—H2A | 121.3 (18) | C15—C14—H14B | 109.0 (16) |
C4—C3—C2 | 120.60 (15) | H14A—C14—H14B | 105 (2) |
C4—C3—H3A | 122.5 (17) | C14—C15—H15A | 108.9 (18) |
C2—C3—H3A | 116.9 (17) | C14—C15—H15B | 110.5 (17) |
C3—C4—C5 | 120.59 (16) | H15A—C15—H15B | 110 (2) |
C3—C4—H4A | 118.0 (16) | C14—C15—H15C | 110.0 (18) |
C5—C4—H4A | 121.4 (16) | H15A—C15—H15C | 109 (2) |
N1—C5—C4 | 117.18 (14) | H15B—C15—H15C | 108 (2) |
N1—C5—C6 | 118.99 (14) | N2—C16—C17 | 112.73 (15) |
C4—C5—C6 | 123.83 (15) | N2—C16—H16A | 109.7 (16) |
C7—C6—C5 | 123.55 (15) | C17—C16—H16A | 109.9 (16) |
C7—C6—H6A | 118.6 (15) | N2—C16—H16B | 108.7 (16) |
C5—C6—H6A | 117.8 (15) | C17—C16—H16B | 107.1 (16) |
C6—C7—C8 | 125.91 (15) | H16A—C16—H16B | 109 (2) |
C6—C7—H7A | 119.8 (15) | C16—C17—H17A | 109.6 (17) |
C8—C7—H7A | 114.3 (15) | C16—C17—H17B | 112.3 (16) |
C9—C8—C13 | 116.92 (14) | H17A—C17—H17B | 106 (2) |
C9—C8—C7 | 124.21 (15) | C16—C17—H17C | 110.5 (17) |
C13—C8—C7 | 118.86 (14) | H17A—C17—H17C | 111 (2) |
C10—C9—C8 | 121.80 (15) | H17B—C17—H17C | 107 (2) |
C10—C9—H9A | 117.3 (14) | N1—C18—H18A | 108.7 (16) |
C8—C9—H9A | 120.8 (14) | N1—C18—H18B | 107.8 (18) |
C9—C10—C11 | 121.30 (15) | H18A—C18—H18B | 110 (2) |
C9—C10—H10A | 120.4 (17) | N1—C18—H18C | 109.5 (17) |
C11—C10—H10A | 118.3 (17) | H18A—C18—H18C | 110 (2) |
N2—C11—C12 | 121.47 (15) | H18B—C18—H18C | 111 (3) |
N2—C11—C10 | 121.47 (15) | ||
C5—N1—C1—C2 | 0.1 (2) | C7—C8—C9—C10 | 179.02 (16) |
C18—N1—C1—C2 | −178.88 (16) | C8—C9—C10—C11 | 0.0 (3) |
N1—C1—C2—C3 | 1.0 (3) | C14—N2—C11—C12 | 177.77 (15) |
C1—C2—C3—C4 | −1.1 (3) | C16—N2—C11—C12 | 0.6 (2) |
C2—C3—C4—C5 | 0.1 (3) | C14—N2—C11—C10 | −2.6 (3) |
C1—N1—C5—C4 | −1.1 (2) | C16—N2—C11—C10 | −179.73 (15) |
C18—N1—C5—C4 | 177.87 (15) | C9—C10—C11—N2 | −179.66 (16) |
C1—N1—C5—C6 | 178.99 (15) | C9—C10—C11—C12 | 0.0 (2) |
C18—N1—C5—C6 | −2.1 (2) | N2—C11—C12—C13 | 179.33 (15) |
C3—C4—C5—N1 | 1.0 (2) | C10—C11—C12—C13 | −0.3 (2) |
C3—C4—C5—C6 | −179.10 (16) | C11—C12—C13—C8 | 0.6 (2) |
N1—C5—C6—C7 | 176.94 (16) | C9—C8—C13—C12 | −0.6 (2) |
C4—C5—C6—C7 | −3.0 (3) | C7—C8—C13—C12 | −179.43 (15) |
C5—C6—C7—C8 | −179.29 (16) | C11—N2—C14—C15 | 84.7 (2) |
C6—C7—C8—C9 | −1.4 (3) | C16—N2—C14—C15 | −98.03 (19) |
C6—C7—C8—C13 | 177.33 (16) | C11—N2—C16—C17 | 79.0 (2) |
C13—C8—C9—C10 | 0.3 (2) | C14—N2—C16—C17 | −98.24 (18) |
Cg2 is the centroid of the C8–C13 ring. |
D—H···A | D—H | H···A | D···A | D—H···A |
C1—H1A···I1i | 0.91 (3) | 2.99 (3) | 3.7980 (18) | 148.8 (19) |
C18—H18B···Cg2ii | 0.94 (3) | 2.79 (3) | 3.6270 (17) | 149 (3) |
Symmetry codes: (i) x, −y+3/2, z+1/2; (ii) −x, −y+1, −z+1. |
Experimental details
Crystal data | |
Chemical formula | C18H23N2+·I− |
Mr | 394.28 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 100 |
a, b, c (Å) | 7.7099 (1), 20.2780 (4), 10.9375 (2) |
β (°) | 92.527 (1) |
V (Å3) | 1708.32 (5) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 1.87 |
Crystal size (mm) | 0.34 × 0.30 × 0.21 |
Data collection | |
Diffractometer | Bruker APEXII CCD area detector diffractometer |
Absorption correction | Multi-scan (SADABS; Bruker, 2005) |
Tmin, Tmax | 0.570, 0.691 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 23707, 6198, 5765 |
Rint | 0.026 |
(sin θ/λ)max (Å−1) | 0.758 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.022, 0.070, 1.10 |
No. of reflections | 6198 |
No. of parameters | 282 |
H-atom treatment | All H-atom parameters refined |
Δρmax, Δρmin (e Å−3) | 0.51, −0.63 |
Computer programs: APEX2 (Bruker, 2005), SAINT (Bruker, 2005), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).
Cg2 is the centroid of the C8–C13 ring. |
D—H···A | D—H | H···A | D···A | D—H···A |
C1—H1A···I1i | 0.91 (3) | 2.99 (3) | 3.7980 (18) | 148.8 (19) |
C18—H18B···Cg2ii | 0.94 (3) | 2.79 (3) | 3.6270 (17) | 149 (3) |
Symmetry codes: (i) x, −y+3/2, z+1/2; (ii) −x, −y+1, −z+1. |
Acknowledgements
The authors thank the Prince of Songkla University for financial support. The authors also thank Universiti Sains Malaysia for the Research University Grant No. 1001/PFIZIK/811160.
References
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For a long time, styryl pyridinium quaternary ammonium compounds were known to exhibit antiseptic properties (Browning et al., 1922, 1923). However medicinal researchers have long neglected to further develop the styryl pyridinium chromophore compounds for use as antibacterial agents due to the superior properties of penicillin until the incoming of the penicillin-resistant bacteria phenomenon, for example, methicillin-resistant Staphylococcus aureus, MRSA. The most interesting feature of styryl pyridinium quaternary ammonium compounds is their very specific activity to MRSA which is a vital drug-resistant bacteria (Wainwright & Kristiansen, 2003; Chanawanno et al., 2010). From this significant reason, our research group has synthesized and characterized several styryl pyridinium derivatives including the title compound (I) in order to search for new potent antibacterial agents. Herein we report the crystal structure of (I).
Figure 1 shows the asymmetric unit of (I), which consists of a C18H23N2+ cation and an I- anion. The cation exists in the E configuration with respect to the C6═C7 double bond [1.350 (2) Å] with the torsion angle C5–C6–C7–C8 = -179.29 (16)°. The pyridinium and benzene rings are nearly coplanar with the ethenyl bridge with the dihedral angle between the pyridinium and benzene rings being 4.63 (7)°. The two ethyl groups of the diethylamino substituent pointed towards the opposite directions with respect to the plane of benzene ring. The conformation of the diethylamino can be indicated by the torsion angles C11–N2–C14–C15 = 84.7 (2)° and C11–N2–C16–C17 = 79.0 (2)°. The bond lengths of cation in (I) are in normal ranges (Allen et al., 1987) and comparable to those in related structures (Chanawanno et al., 2008; Fun et al., 2009).
In the crystal packing (Fig. 2), the cations are arranged in a zig-zag manner along the b axis with the iodide ions located in the interstitials of the cations and linked to the cations by a C—H···I weak interaction (Table 1). The cations stacked approximately along the a axis in an antiparallel manner by π–π interaction with the Cg1···Cg2iii distance of 3.5262 (9) Å [symmetry code: (iii) 1-x, 1-y, 1-z]; Cg1 and Cg2 are centroids of N1/C1–C5 and C8–C13 rings, respectively. The crystal structure is further stabilized by C—H···π interactions (Table 1).