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Acta Crystallogr Sect E Struct Rep Online. 2010 September 1; 66(Pt 9): o2455.
Published online 2010 August 28. doi:  10.1107/S1600536810033490
PMCID: PMC3007914

1,1′,2,2′-Tetra­methyl-3,3′-(p-phenyl­enedimethyl­ene)diimidazol-1-ium bis­(trifluoro­methane­sulfonate)

Abstract

In the solid form of the title imidazolium-based ionic liquid salt, C18H24N4 2+·2CF3SO3 , the complete cation is generated by a crystallographic inversion centre. The five-membered imidazole ring is approximately perpendicular to the six-membered phenyl­ene ring [dihedral angle = 85.11 (11)°]. In the crystal, the components are linked by C—H(...)O interactions.

Related literature

For background to imidazolium-based ionic liquid salts, see: Ganesan et al. (2008 [triangle]); Puvaneswary et al. (2009a [triangle],b [triangle],c [triangle]).

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Object name is e-66-o2455-scheme1.jpg

Experimental

Crystal data

  • C18H24N4 2+·2CF3O3S
  • M r = 594.55
  • Triclinic, An external file that holds a picture, illustration, etc.
Object name is e-66-o2455-efi1.jpg
  • a = 7.3054 (1) Å
  • b = 8.0645 (2) Å
  • c = 11.3548 (2) Å
  • α = 89.946 (1)°
  • β = 76.653 (1)°
  • γ = 75.213 (1)°
  • V = 628.14 (2) Å3
  • Z = 1
  • Mo Kα radiation
  • μ = 0.30 mm−1
  • T = 100 K
  • 0.31 × 0.19 × 0.04 mm

Data collection

  • Bruker APEXII CCD diffractometer
  • Absorption correction: multi-scan (SADABS; Sheldrick, 1996 [triangle]) T min = 0.912, T max = 0.988
  • 5105 measured reflections
  • 2273 independent reflections
  • 1982 reflections with I > 2σ(I)
  • R int = 0.021

Refinement

  • R[F 2 > 2σ(F 2)] = 0.042
  • wR(F 2) = 0.103
  • S = 1.16
  • 2273 reflections
  • 174 parameters
  • H-atom parameters constrained
  • Δρmax = 0.33 e Å−3
  • Δρmin = −0.37 e Å−3

Data collection: APEX2 (Bruker, 2008 [triangle]); cell refinement: SAINT (Bruker, 2008 [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: X-SEED (Barbour, 2001 [triangle]); software used to prepare material for publication: publCIF (Westrip, 2010 [triangle]).

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810033490/hg2702sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810033490/hg2702Isup2.hkl

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

Acknowledgments

The authors would like to thank the University of Malaya for the financial support (grant Nos. RG062–09SUS and TA021–2009A).

supplementary crystallographic information

Comment

Crystal structures of similar symmetrical compunds have been reported from our previous studies (Ganesan, et al., 2008; Puvaneswary et al., 2009a; 2009b; 2009c). As part of our ongoing research into imidazolium-based ionic liquids, we have synthesized 1,1',2,2'-tetramethyl-3,3'-(p-phenylenedimethylene)diimidazolium salt with trifluoromethanesulfonate anion.

The neighbouring cations in the title compund are held together via C–H···O hydrogen bonds in opposite directions through imidazole rings to CF3SO3- anions and these hydrogen bonds stabilize the crystal structure.

Experimental

α,α-Dibromo-p-xylene (1.26 g, 4.77 mmol) and 1,2-dimethylimidazole (0.96 g, 9.99 mmol) were refluxed in DMF (50 ml) for 3 h. The product that separated from solution was collected and washed with ether. Crystals of the bromide salt were grown from its solution in water (Puvaneswary et al., 2009a).

The bromide salt (0.50 g, 1.10 mmol) and lithium trifluoromethanesulfonate (0.36 g, 2.31 mmol) were stirred in water (100 ml) for 24 h. Colourless crystals were obtained by slow evaporation of the solution (Melting point: 92–94°C).

Refinement

Carbon-bound H-atoms were placed in calculated positions (C—H 0.95 to 0.99Å)and were included in the refinement in the riding model approximation, with U(H) set to 1.2 to 1.5Ueq(C).

Figures

Fig. 1.
Thermal ellipsoid plot of the title compund at the 50% probability level. H atoms are drawn as spheres of arbitrary radius.

Crystal data

C18H24N42+·2CF3O3SZ = 1
Mr = 594.55F(000) = 306
Triclinic, P1Dx = 1.572 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 7.3054 (1) ÅCell parameters from 1992 reflections
b = 8.0645 (2) Åθ = 2.6–29.0°
c = 11.3548 (2) ŵ = 0.30 mm1
α = 89.946 (1)°T = 100 K
β = 76.653 (1)°Plate, colourless
γ = 75.213 (1)°0.31 × 0.19 × 0.04 mm
V = 628.14 (2) Å3

Data collection

Bruker APEXII CCD diffractometer2273 independent reflections
Radiation source: fine-focus sealed tube1982 reflections with I > 2σ(I)
graphiteRint = 0.021
[var phi] and ω scansθmax = 25.3°, θmin = 1.9°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)h = −8→8
Tmin = 0.912, Tmax = 0.988k = −9→9
5105 measured reflectionsl = −13→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)] = 0.042Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.103H-atom parameters constrained
S = 1.16w = 1/[σ2(Fo2) + (0.0241P)2 + 1.0056P] where P = (Fo2 + 2Fc2)/3
2273 reflections(Δ/σ)max < 0.001
174 parametersΔρmax = 0.33 e Å3
0 restraintsΔρmin = −0.37 e Å3

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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 > σ(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.

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

xyzUiso*/Ueq
N10.1441 (3)0.2762 (3)0.18655 (19)0.0160 (5)
N20.3402 (3)0.2113 (3)0.30441 (19)0.0154 (5)
C1−0.0172 (4)0.3018 (3)0.4080 (2)0.0184 (6)
H1A−0.11680.40260.39490.028*
H1B0.02510.32410.48100.028*
H1C−0.07180.20220.41840.028*
C20.1513 (4)0.2664 (3)0.3023 (2)0.0153 (5)
C3−0.0369 (4)0.3301 (4)0.1445 (3)0.0214 (6)
H3A−0.11690.24980.17030.032*
H3B−0.00500.33040.05580.032*
H3C−0.10930.44590.17930.032*
C40.3304 (4)0.2260 (3)0.1129 (2)0.0192 (6)
H40.36510.22140.02680.023*
C50.4525 (4)0.1851 (3)0.1863 (2)0.0191 (6)
H50.59060.14540.16200.023*
C60.4164 (4)0.1924 (3)0.4137 (2)0.0165 (6)
H6A0.53890.09920.39700.020*
H6B0.32140.15750.47960.020*
C70.4564 (3)0.3550 (3)0.4568 (2)0.0144 (5)
C80.4553 (4)0.4977 (3)0.3878 (2)0.0166 (6)
H80.42470.49740.31090.020*
C90.5011 (4)0.3589 (3)0.5692 (2)0.0155 (5)
H90.50180.26240.61730.019*
S11.07181 (10)0.18928 (9)0.76648 (6)0.01802 (18)
F10.7150 (2)0.1636 (2)0.78601 (16)0.0331 (4)
F20.7393 (2)0.3543 (2)0.91048 (16)0.0334 (4)
F30.8292 (2)0.0858 (2)0.94182 (14)0.0272 (4)
O11.0372 (3)0.3265 (3)0.68688 (17)0.0283 (5)
O21.1362 (3)0.0188 (3)0.70802 (19)0.0332 (5)
O31.1741 (3)0.2164 (3)0.85592 (18)0.0262 (5)
C100.8268 (4)0.1991 (3)0.8556 (2)0.0204 (6)

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
N10.0189 (12)0.0156 (11)0.0150 (11)−0.0052 (9)−0.0060 (9)−0.0006 (9)
N20.0154 (11)0.0174 (12)0.0136 (11)−0.0046 (9)−0.0035 (9)0.0001 (9)
C10.0180 (14)0.0191 (14)0.0177 (13)−0.0044 (11)−0.0039 (11)0.0009 (11)
C20.0188 (13)0.0130 (13)0.0162 (13)−0.0063 (11)−0.0059 (11)0.0002 (10)
C30.0221 (15)0.0233 (15)0.0215 (14)−0.0053 (12)−0.0111 (12)0.0003 (11)
C40.0247 (15)0.0190 (14)0.0136 (13)−0.0081 (12)−0.0009 (11)−0.0017 (10)
C50.0173 (14)0.0215 (14)0.0174 (14)−0.0062 (11)−0.0007 (11)−0.0032 (11)
C60.0160 (13)0.0192 (14)0.0157 (13)−0.0050 (11)−0.0060 (10)0.0020 (10)
C70.0073 (12)0.0192 (13)0.0151 (13)−0.0022 (10)−0.0011 (10)−0.0011 (10)
C80.0150 (13)0.0227 (14)0.0123 (12)−0.0038 (11)−0.0047 (10)0.0009 (10)
C90.0131 (13)0.0171 (13)0.0155 (13)−0.0022 (10)−0.0041 (10)0.0029 (10)
S10.0180 (4)0.0213 (4)0.0143 (3)−0.0061 (3)−0.0019 (3)−0.0007 (3)
F10.0283 (10)0.0448 (11)0.0367 (10)−0.0189 (8)−0.0182 (8)0.0115 (8)
F20.0254 (9)0.0241 (9)0.0409 (11)0.0004 (7)0.0038 (8)−0.0048 (8)
F30.0329 (10)0.0300 (9)0.0213 (9)−0.0150 (8)−0.0044 (7)0.0088 (7)
O10.0382 (12)0.0340 (12)0.0190 (10)−0.0182 (10)−0.0098 (9)0.0098 (9)
O20.0293 (12)0.0287 (12)0.0355 (13)−0.0059 (9)0.0024 (10)−0.0137 (10)
O30.0222 (11)0.0357 (12)0.0227 (11)−0.0089 (9)−0.0081 (8)0.0034 (9)
C100.0216 (15)0.0187 (14)0.0209 (14)−0.0047 (11)−0.0060 (12)0.0023 (11)

Geometric parameters (Å, °)

N1—C21.329 (3)C6—C71.520 (4)
N1—C41.382 (3)C6—H6A0.9900
N1—C31.471 (3)C6—H6B0.9900
N2—C21.343 (3)C7—C91.390 (4)
N2—C51.386 (3)C7—C81.391 (4)
N2—C61.466 (3)C8—C9i1.392 (4)
C1—C21.475 (4)C8—H80.9500
C1—H1A0.9800C9—C8i1.392 (4)
C1—H1B0.9800C9—H90.9500
C1—H1C0.9800S1—O11.438 (2)
C3—H3A0.9800S1—O31.439 (2)
C3—H3B0.9800S1—O21.442 (2)
C3—H3C0.9800S1—C101.824 (3)
C4—C51.339 (4)F1—C101.338 (3)
C4—H40.9500F2—C101.331 (3)
C5—H50.9500F3—C101.338 (3)
C2—N1—C4109.9 (2)N2—C6—C7113.6 (2)
C2—N1—C3124.5 (2)N2—C6—H6A108.8
C4—N1—C3125.6 (2)C7—C6—H6A108.8
C2—N2—C5109.0 (2)N2—C6—H6B108.8
C2—N2—C6125.6 (2)C7—C6—H6B108.8
C5—N2—C6125.3 (2)H6A—C6—H6B107.7
C2—C1—H1A109.5C9—C7—C8118.8 (2)
C2—C1—H1B109.5C9—C7—C6118.2 (2)
H1A—C1—H1B109.5C8—C7—C6123.0 (2)
C2—C1—H1C109.5C7—C8—C9i120.3 (2)
H1A—C1—H1C109.5C7—C8—H8119.8
H1B—C1—H1C109.5C9i—C8—H8119.8
N1—C2—N2107.0 (2)C7—C9—C8i120.9 (2)
N1—C2—C1126.3 (2)C7—C9—H9119.5
N2—C2—C1126.6 (2)C8i—C9—H9119.5
N1—C3—H3A109.5O1—S1—O3115.23 (12)
N1—C3—H3B109.5O1—S1—O2115.05 (13)
H3A—C3—H3B109.5O3—S1—O2114.61 (13)
N1—C3—H3C109.5O1—S1—C10102.57 (13)
H3A—C3—H3C109.5O3—S1—C10103.71 (12)
H3B—C3—H3C109.5O2—S1—C10103.25 (13)
C5—C4—N1106.8 (2)F2—C10—F3107.4 (2)
C5—C4—H4126.6F2—C10—F1107.8 (2)
N1—C4—H4126.6F3—C10—F1107.1 (2)
C4—C5—N2107.3 (2)F2—C10—S1111.33 (19)
C4—C5—H5126.4F3—C10—S1111.72 (19)
N2—C5—H5126.4F1—C10—S1111.34 (19)

Symmetry codes: (i) −x+1, −y+1, −z+1.

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
C6—H6A···O2ii0.992.353.251 (3)152.
C3—H3A···O2iii0.982.593.424 (4)144.
C1—H1C···O2iii0.982.493.296 (3)139.
C1—H1B···O1iv0.982.363.293 (3)159.
C1—H1A···O1i0.982.523.164 (3)123.

Symmetry codes: (ii) −x+2, −y, −z+1; (iii) −x+1, −y, −z+1; (iv) x−1, y, z; (i) −x+1, −y+1, −z+1.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: HG2702).

References

  • Barbour, L. J. (2001). J. Supramol. Chem.1, 189–191.
  • Bruker (2008). APEX2 and SAINT Bruker AXS Inc., Madison, Wisconsin, USA.
  • Ganesan, K., Alias, Y. & Ng, S. W. (2008). Acta Cryst. C64, o478–o480. [PubMed]
  • Puvaneswary, S., Alias, Y. & Ng, S. W. (2009a). Acta Cryst. E65, o1828. [PMC free article] [PubMed]
  • Puvaneswary, S., Alias, Y. & Ng, S. W. (2009b). Acta Cryst. E65, o1829. [PMC free article] [PubMed]
  • Puvaneswary, S., Alias, Y. & Ng, S. W. (2009c). Acta Cryst. E65, o1830. [PMC free article] [PubMed]
  • Sheldrick, G. M. (1996). SADABS University of Göttingen, Germany.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Westrip, S. P. (2010). J. Appl. Cryst.43, 920–925.

Articles from Acta Crystallographica Section E: Structure Reports Online are provided here courtesy of International Union of Crystallography