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Acta Crystallogr Sect E Struct Rep Online. 2009 August 1; 65(Pt 8): o2027.
Published online 2009 July 29. doi:  10.1107/S1600536809028967
PMCID: PMC2977116

3,3′-Dimethyl-1,1′-methyl­ene­diimidazolium dibromide

Abstract

In the crystal structure of the title compound, C9H14N4 2+·2Br, the cation and anions have crystallographic mirror symmetry, with the mirror plane running through the central CH2 group for the cation. The latter are stacked along the a axis, forming channels hosting the bromide anions. The crystal packing is stabilized by C—H(...)Br hydrogen-bonding inter­actions, generating a two-dimensional network.

Related literature

For related structures, see: Jin et al. (2007 [triangle]); Eicher et al. (2003 [triangle]).

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Object name is e-65-o2027-scheme1.jpg

Experimental

Crystal data

  • C9H14N4 2+·2Br
  • M r = 338.06
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-65-o2027-efi1.jpg
  • a = 4.7310 (5) Å
  • b = 11.3861 (12) Å
  • c = 11.8419 (15) Å
  • β = 93.672 (1)°
  • V = 636.59 (12) Å3
  • Z = 2
  • Mo Kα radiation
  • μ = 6.34 mm−1
  • T = 298 K
  • 0.32 × 0.10 × 0.07 mm

Data collection

  • Bruker SMART diffractometer
  • Absorption correction: multi-scan (SADABS; Sheldrick, 1996 [triangle]) T min = 0.227, T max = 0.638
  • 3349 measured reflections
  • 1188 independent reflections
  • 928 reflections with I > 2σ(I)
  • R int = 0.031

Refinement

  • R[F 2 > 2σ(F 2)] = 0.028
  • wR(F 2) = 0.066
  • S = 1.07
  • 1188 reflections
  • 74 parameters
  • H-atom parameters constrained
  • Δρmax = 0.63 e Å−3
  • Δρmin = −0.27 e Å−3

Data collection: SMART (Siemens, 1996 [triangle]); cell refinement: SAINT (Siemens, 1996 [triangle]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: SHELXTL (Sheldrick, 2008 [triangle]); software used to prepare material for publication: SHELXTL.

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809028967/rz2350sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809028967/rz2350Isup2.hkl

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

Acknowledgments

We acknowledge financial support by the National Natural Science Foundation of China (20773081, 20873074) and the National Basic Research Program (2007CB808004, 2009CB30101).

supplementary crystallographic information

Comment

The title compound was synthesized as the precursor of a chelating N-heterocyclic carbene ligand, which can be generated by deprotonating the ring between the two N atoms of the two imidazolium cations.(Jin et al., 2007).

The structure consists of dimethylethylenediimidazolium cations and bromide anions (Fig. 1). The cation has crystallographically imposed mirror symmetry, with atom C1 located on a mirror plane. Both independent bromide anions also lie on a mirror plane. The C1—N1 bond length is 1.455 (4) Å, and the N1—C1—N1 bond angle is 111.0 (4)°. The C2—N1—C4 bond angle of 108.4 (3)° is similar to those observed in free imidazole (Eicher et al., 2003). The relative orientation of the imidazolium ring with respect to the other imidazolium ring can be described by the value of -95.4 (4)° of the C2—N1—C1—N1 torsion angle. In the crystal, the cations are stacked along the a axis forming channels that are occupied by the bromide anions (Fig. 2). Adjacent molecules are connected into a two-dimensional network through C—H···Br hydrogen interactions (Table 1).

Experimental

A mixture of 1-methylimidazole (0.1 mol) and dichloromethane (0.05 mol) was reacted under nitrogen atmosphere with stirring at 350 K for 48 h. The resulting clear solution was evaporated under vacuum. Colourless crystals suitable for X-ray analysis were obtained by slow evaporation of a ethyl acetate solution over a period of two weeks. (yield 83%) Anal. Calcd (%) for C9H14Br2N4 (Mr = 338.06): C, 32.03; H, 4.09; N, 16.62. Found (%): C, 31.95; H, 4.14; N, 16.57.

Refinement

All H atoms were placed geometrically and treated as riding on their parent atoms, with C—H = 0.93–0.97 Å, and with Uiso(H) = 1.2Ueq(C) or 1.5Ueq(C) for methyl H atoms.

Figures

Fig. 1.
The molecular structure of the compound, with atom labels and 50% probability displacement ellipsoids. Unlabelled atoms are related to labelled atoms by (x, 0.5-y, z)
Fig. 2.
Crystal packing of the compound, showing the two-dimensional network structure formed by C—H···Br hydrogen bonds (dashed lines).

Crystal data

C9H14N42+·2BrF(000) = 332
Mr = 338.06Dx = 1.764 Mg m3
Monoclinic, P21/mMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybCell parameters from 1657 reflections
a = 4.7310 (5) Åθ = 2.5–26.3°
b = 11.3861 (12) ŵ = 6.34 mm1
c = 11.8419 (15) ÅT = 298 K
β = 93.672 (1)°Block, colourless
V = 636.59 (12) Å30.32 × 0.10 × 0.07 mm
Z = 2

Data collection

Bruker SMART diffractometer1188 independent reflections
Radiation source: fine-focus sealed tube928 reflections with I > 2σ(I)
graphiteRint = 0.031
[var phi] and ω scansθmax = 25.0°, θmin = 1.7°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)h = −5→5
Tmin = 0.227, Tmax = 0.638k = −13→10
3349 measured reflectionsl = −14→13

Refinement

Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.028Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.066H-atom parameters constrained
S = 1.07w = 1/[σ2(Fo2) + (0.0319P)2] where P = (Fo2 + 2Fc2)/3
1188 reflections(Δ/σ)max < 0.001
74 parametersΔρmax = 0.63 e Å3
0 restraintsΔρmin = −0.27 e Å3

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2)

xyzUiso*/Ueq
Br10.14906 (11)0.75000.12842 (4)0.04708 (18)
Br20.86811 (10)0.25000.43062 (4)0.04621 (18)
N10.3731 (5)0.3553 (2)0.18410 (19)0.0333 (6)
N20.5612 (5)0.5023 (2)0.2736 (2)0.0375 (6)
C10.2048 (10)0.25000.1615 (4)0.0410 (11)
H1A0.13190.25000.08310.049*
H1B0.04470.25000.20880.049*
C20.3825 (7)0.4151 (3)0.2809 (2)0.0361 (8)
H20.27960.39780.34310.043*
C30.6745 (7)0.4977 (3)0.1702 (3)0.0450 (8)
H30.80810.54900.14360.054*
C40.5580 (7)0.4061 (3)0.1145 (3)0.0421 (8)
H40.59530.38140.04210.050*
C50.6396 (9)0.5872 (3)0.3625 (3)0.0699 (13)
H5A0.47420.62960.38200.105*
H5B0.77640.64120.33600.105*
H5C0.71970.54660.42800.105*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
Br10.0526 (4)0.0461 (3)0.0433 (3)0.0000.0087 (2)0.000
Br20.0433 (3)0.0484 (3)0.0471 (3)0.0000.0040 (2)0.000
N10.0389 (16)0.0264 (14)0.0339 (14)0.0034 (12)−0.0035 (12)0.0049 (12)
N20.0483 (17)0.0230 (14)0.0405 (15)−0.0001 (14)−0.0022 (13)−0.0011 (12)
C10.041 (3)0.037 (3)0.043 (3)0.000−0.008 (2)0.000
C20.043 (2)0.0321 (18)0.0327 (16)0.0052 (16)0.0014 (14)−0.0011 (14)
C30.053 (2)0.0311 (18)0.051 (2)−0.0003 (17)0.0103 (17)0.0093 (17)
C40.055 (2)0.0358 (18)0.0355 (17)0.0082 (17)0.0063 (16)0.0059 (16)
C50.109 (4)0.042 (2)0.058 (3)−0.019 (2)0.003 (2)−0.0142 (19)

Geometric parameters (Å, °)

N1—C21.331 (3)C1—H1B0.9700
N1—C41.368 (4)C2—H20.9300
N1—C11.455 (4)C3—C41.334 (4)
N2—C21.311 (4)C3—H30.9300
N2—C31.370 (4)C4—H40.9300
N2—C51.459 (4)C5—H5A0.9600
C1—N1i1.455 (4)C5—H5B0.9600
C1—H1A0.9700C5—H5C0.9600
C2—N1—C4108.4 (3)N1—C2—H2125.8
C2—N1—C1124.6 (3)C4—C3—N2107.4 (3)
C4—N1—C1127.0 (3)C4—C3—H3126.3
C2—N2—C3108.7 (3)N2—C3—H3126.3
C2—N2—C5126.1 (3)C3—C4—N1107.0 (3)
C3—N2—C5125.1 (3)C3—C4—H4126.5
N1—C1—N1i111.0 (4)N1—C4—H4126.5
N1—C1—H1A109.4N2—C5—H5A109.5
N1i—C1—H1A109.4N2—C5—H5B109.5
N1—C1—H1B109.4H5A—C5—H5B109.5
N1i—C1—H1B109.4N2—C5—H5C109.5
H1A—C1—H1B108.0H5A—C5—H5C109.5
N2—C2—N1108.5 (3)H5B—C5—H5C109.5
N2—C2—H2125.8
C2—N1—C1—N1i−95.4 (4)C2—N2—C3—C40.6 (4)
C4—N1—C1—N1i80.7 (4)C5—N2—C3—C4177.6 (3)
C3—N2—C2—N1−1.1 (3)N2—C3—C4—N10.2 (4)
C5—N2—C2—N1−178.2 (3)C2—N1—C4—C3−0.9 (4)
C4—N1—C2—N21.2 (3)C1—N1—C4—C3−177.5 (3)
C1—N1—C2—N2177.9 (3)

Symmetry codes: (i) x, −y+1/2, z.

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
C4—H4···Br1ii0.932.843.724 (3)158
C3—H3···Br1iii0.932.813.699 (3)160
C1—H1A···Br1iv0.972.763.723 (4)172
C2—H2···Br2v0.932.823.627 (3)146
C1—H1B···Br2v0.972.813.652 (5)146

Symmetry codes: (ii) −x+1, −y+1, −z; (iii) x+1, y, z; (iv) −x, −y+1, −z; (v) x−1, y, z.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: RZ2350).

References

  • Eicher, T., Hauptmann, S. & Speicher, A. (2003). The Chemistry of Heterocycles: Structures, Reactions, Synthesis and Applications, 2th ed. Weinheim: Wiley-VCH.
  • Jin, H.-S., Wang, H.-J., Zhang, Y., Zuo, Y.-J. & Zhong, C.-M. (2007). Acta Cryst. E63, o1880–o1881.
  • Sheldrick, G. M. (1996). SADABS University of Göttingen, Germany.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Siemens (1996). SMART and SAINT Siemens Analytical X-ray Instruments Inc., Madison, Wisconsin, USA.

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