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

Puvaneswary, S.; Alias, Y.; Ng, S.W.

doi:10.1107/S1600536809026312

organic compounds

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ISSN: 2056-9890

Volume 65| Part 8| August 2009| Page o1829

doi:10.1107/S1600536809026312

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

Subramaniam Puvaneswary,^a Yatimah Alias ^a and Seik Weng Ng ^a ^*

^aDepartment of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia
^*Correspondence e-mail: seikweng@um.edu.my

(Received 4 July 2009; accepted 6 July 2009; online 11 July 2009)

The title imidazolium-based ionic-liquid salt, C₁₈H₂₄N₄²⁺·2BF₄⁻, has the cation lying about a center of inversion. The five-membered imidazole ring is approximately perpendicular to the six-membered phenylene ring [dihedral angle = 86.9 (1)°]. The tetrafluoroborate anion is disordered over two sites in a 0.722 (3):0.278 (3) ratio.

Related literature

For background to imidazolium-based ionic liquid salts, see: Ganesan et al. (2008 ).

Experimental

Crystal data

C₁₈H₂₄N₄²⁺·2BF₄⁻
M_r = 470.03
Monoclinic, P 2₁ /n
a = 8.9095 (2) Å
b = 10.2254 (2) Å
c = 11.7113 (3) Å
β = 93.024 (1)°
V = 1065.45 (4) Å³
Z = 2
Mo Kα radiation
μ = 0.14 mm⁻¹
T = 140 K
0.40 × 0.35 × 0.05 mm

Data collection

Bruker SMART APEX diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ) T_min = 0.948, T_max = 0.993
7256 measured reflections
2418 independent reflections
2063 reflections with I > 2σ(I)
R_int = 0.017

Refinement

R[F² > 2σ(F²)] = 0.047
wR(F²) = 0.140
S = 1.03
2418 reflections
193 parameters
124 restraints
H-atom parameters constrained
Δρ_max = 0.42 e Å⁻³
Δρ_min = −0.22 e Å⁻³

Data collection: APEX2 (Bruker, 2008 ); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: X-SEED (Barbour, 2001 ); software used to prepare material for publication: publCIF (Westrip, 2009 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809026312/tk2495sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809026312/tk2495Isup2.hkl

checkCIF report

Related literature top

For background to imidazolium-based ionic liquid salts, see: Ganesan et al. (2008).

Experimental top

α,α-Dibromo-p-xylene (0.78 g, 3 mmol) and 1,2-dimethylimidazole (0.58 g, 6 mmol) were refluxed in DMF (50 ml) for 3 h. The product that separated from solution was collected and washed with ether. Crystals were grown from its solution in water.

The bromide salt (0.46 g, 1 mmol) and sodium tetrafluoroborate (0.11 g, 1 mol) were stirred in water (100 ml) for 24 h. The product that separated from solution was collected and washed with ethanol. Crystals were grown from its solution in DMF.

Computing details top

Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT (Bruker, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: X-SEED (Barbour, 2001); software used to prepare material for publication: publCIF (Westrip, 2009).

Figures top

Fig. 1. Thermal ellipsoid plot (Barbour, 2001) of [C₁₈H₂₄N₄]²⁺ 2[BF₄]^- at the 70% probability level; hydrogen atoms are drawn as spheres of arbitrary radius. The [BF₄]^- anion is disordered; the minor component of the disorder is not shown. The non-H atoms comprising the asymmetric unit are labelled and the unlabelled atoms are related by 1-x, 1-y, -z.

1,1',2,2'-Tetramethyl-3,3'-(p-phenylenedimethylene)diimidazol-1-ium bis(tetrafluoridoborate) top

Crystal data top

C₁₈H₂₄N₄²⁺·2BF₄⁻	F(000) = 484
M_r = 470.03	D_x = 1.465 Mg m⁻³
Monoclinic, P2₁/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 3223 reflections
a = 8.9095 (2) Å	θ = 2.6–28.2°
b = 10.2254 (2) Å	µ = 0.14 mm⁻¹
c = 11.7113 (3) Å	T = 140 K
β = 93.024 (1)°	Irregular block, colorless
V = 1065.45 (4) Å³	0.40 × 0.35 × 0.05 mm
Z = 2

Data collection top

Bruker SMART APEX diffractometer	2418 independent reflections
Radiation source: fine-focus sealed tube	2063 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.017
ω scans	θ_max = 27.5°, θ_min = 2.7°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −11→11
T_min = 0.948, T_max = 0.993	k = −12→13
7256 measured reflections	l = −15→15

Refinement top

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)] = 0.047	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.140	H-atom parameters constrained
S = 1.03	w = 1/[σ²(F_o²) + (0.0793P)² + 0.4801P] where P = (F_o² + 2F_c²)/3
2418 reflections	(Δ/σ)_max < 0.001
193 parameters	Δρ_max = 0.42 e Å⁻³
124 restraints	Δρ_min = −0.22 e Å⁻³

Crystal data top

C₁₈H₂₄N₄²⁺·2BF₄⁻	V = 1065.45 (4) Å³
M_r = 470.03	Z = 2
Monoclinic, P2₁/n	Mo Kα radiation
a = 8.9095 (2) Å	µ = 0.14 mm⁻¹
b = 10.2254 (2) Å	T = 140 K
c = 11.7113 (3) Å	0.40 × 0.35 × 0.05 mm
β = 93.024 (1)°

Data collection top

Bruker SMART APEX diffractometer	2418 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	2063 reflections with I > 2σ(I)
T_min = 0.948, T_max = 0.993	R_int = 0.017
7256 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.047	124 restraints
wR(F²) = 0.140	H-atom parameters constrained
S = 1.03	Δρ_max = 0.42 e Å⁻³
2418 reflections	Δρ_min = −0.22 e Å⁻³
193 parameters

Special details top

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.

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

	x	y	z	U_iso*/U_eq	Occ. (<1)
F1	0.5880 (4)	0.1389 (5)	0.7595 (4)	0.0560 (16)	0.722 (3)
F2	0.3734 (4)	0.1621 (3)	0.8509 (2)	0.0798 (12)	0.722 (3)
F3	0.4339 (3)	−0.0345 (2)	0.7799 (3)	0.0564 (7)	0.722 (3)
F4	0.3648 (2)	0.1294 (2)	0.66391 (16)	0.0572 (6)	0.722 (3)
F1'	0.5870 (8)	0.1500 (9)	0.7551 (6)	0.025 (2)	0.278 (3)
F2'	0.3434 (6)	0.1720 (6)	0.7957 (7)	0.065 (2)	0.278 (3)
F3'	0.4968 (6)	0.0503 (6)	0.9079 (4)	0.0664 (17)	0.278 (3)
F4'	0.4287 (12)	−0.0201 (7)	0.7334 (7)	0.099 (4)	0.278 (3)
N1	0.53432 (15)	0.55200 (13)	0.81766 (11)	0.0262 (3)
N2	0.69734 (16)	0.64335 (14)	0.93417 (11)	0.0278 (3)
C1	0.38756 (18)	0.46412 (16)	0.41995 (14)	0.0277 (4)
H1	0.3101	0.4392	0.3655	0.033*
C2	0.36751 (18)	0.44717 (16)	0.53553 (14)	0.0275 (4)
H2	0.2761	0.4110	0.5595	0.033*
C3	0.47960 (17)	0.48256 (14)	0.61695 (13)	0.0247 (3)
C4	0.4550 (2)	0.45769 (16)	0.74175 (14)	0.0291 (4)
H4A	0.3460	0.4621	0.7541	0.035*
H4B	0.4900	0.3683	0.7619	0.035*
C7	0.66006 (18)	0.53075 (16)	0.88270 (13)	0.0264 (4)
C9	0.7447 (2)	0.40622 (18)	0.89444 (17)	0.0382 (4)
H9A	0.6774	0.3329	0.8749	0.057*
H9B	0.7850	0.3966	0.9735	0.057*
H9C	0.8277	0.4069	0.8427	0.057*
C8	0.8332 (2)	0.66710 (19)	1.00765 (15)	0.0368 (4)
H8A	0.8437	0.5982	1.0657	0.055*
H8B	0.8252	0.7522	1.0453	0.055*
H8C	0.9214	0.6667	0.9611	0.055*
C6	0.5949 (2)	0.73843 (17)	0.89965 (15)	0.0324 (4)
H6	0.5962	0.8274	0.9229	0.039*
C5	0.4932 (2)	0.68179 (17)	0.82714 (15)	0.0322 (4)
H5	0.4089	0.7230	0.7894	0.039*
B1	0.4413 (4)	0.0981 (4)	0.7654 (3)	0.0246 (8)	0.722 (3)
B1'	0.4639 (8)	0.0891 (8)	0.7968 (6)	0.026 (3)	0.278 (3)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
F1	0.033 (3)	0.057 (2)	0.077 (3)	−0.0039 (17)	−0.0074 (19)	0.0112 (18)
F2	0.123 (3)	0.0547 (16)	0.0673 (16)	−0.0125 (16)	0.0595 (18)	−0.0215 (14)
F3	0.0532 (13)	0.0217 (9)	0.095 (2)	0.0044 (8)	0.0083 (13)	0.0100 (11)
F4	0.0433 (10)	0.0755 (13)	0.0509 (11)	−0.0056 (9)	−0.0156 (8)	0.0165 (9)
F1'	0.024 (5)	0.027 (3)	0.025 (3)	−0.003 (3)	0.005 (3)	−0.006 (2)
F2'	0.0158 (19)	0.035 (2)	0.146 (7)	0.0079 (17)	0.016 (3)	0.011 (4)
F3'	0.068 (3)	0.086 (4)	0.047 (3)	0.011 (3)	0.009 (2)	0.009 (2)
F4'	0.092 (5)	0.082 (6)	0.123 (7)	−0.031 (5)	0.011 (5)	−0.072 (5)
N1	0.0254 (7)	0.0273 (7)	0.0257 (7)	0.0001 (5)	−0.0009 (5)	0.0001 (5)
N2	0.0284 (7)	0.0327 (7)	0.0223 (6)	−0.0002 (5)	0.0007 (5)	−0.0026 (5)
C1	0.0228 (8)	0.0289 (8)	0.0305 (8)	−0.0023 (6)	−0.0060 (6)	−0.0037 (6)
C2	0.0214 (8)	0.0275 (8)	0.0334 (8)	−0.0034 (6)	−0.0007 (6)	−0.0019 (6)
C3	0.0241 (7)	0.0201 (7)	0.0294 (8)	0.0014 (6)	−0.0028 (6)	−0.0015 (6)
C4	0.0296 (8)	0.0268 (8)	0.0303 (8)	−0.0052 (6)	−0.0047 (6)	0.0003 (6)
C7	0.0279 (8)	0.0297 (8)	0.0215 (7)	0.0009 (6)	0.0011 (6)	0.0010 (6)
C9	0.0391 (10)	0.0313 (9)	0.0432 (10)	0.0078 (7)	−0.0079 (8)	0.0001 (7)
C8	0.0362 (9)	0.0441 (10)	0.0291 (8)	−0.0030 (8)	−0.0075 (7)	−0.0070 (7)
C6	0.0351 (9)	0.0283 (8)	0.0338 (9)	0.0043 (7)	0.0031 (7)	−0.0039 (7)
C5	0.0320 (9)	0.0290 (8)	0.0353 (9)	0.0061 (7)	−0.0013 (7)	0.0007 (7)
B1	0.0270 (16)	0.0229 (14)	0.0234 (18)	0.0008 (11)	−0.0033 (14)	−0.0002 (12)
B1'	0.022 (4)	0.032 (4)	0.023 (5)	0.005 (3)	−0.012 (3)	−0.006 (3)

Geometric parameters (Å, º) top

F1—B1	1.377 (4)	C2—C3	1.392 (2)
F2—B1	1.364 (4)	C2—H2	0.9500
F3—B1	1.368 (4)	C3—C1ⁱ	1.392 (2)
F4—B1	1.376 (4)	C3—C4	1.511 (2)
F1'—B1'	1.373 (7)	C4—H4A	0.9900
F2'—B1'	1.368 (6)	C4—H4B	0.9900
F3'—B1'	1.377 (6)	C7—C9	1.483 (2)
F4'—B1'	1.368 (7)	C9—H9A	0.9800
N1—C7	1.339 (2)	C9—H9B	0.9800
N1—C5	1.383 (2)	C9—H9C	0.9800
N1—C4	1.467 (2)	C8—H8A	0.9800
N2—C7	1.333 (2)	C8—H8B	0.9800
N2—C6	1.379 (2)	C8—H8C	0.9800
N2—C8	1.468 (2)	C6—C5	1.340 (2)
C1—C2	1.386 (2)	C6—H6	0.9500
C1—C3ⁱ	1.392 (2)	C5—H5	0.9500
C1—H1	0.9500

C7—N1—C5	109.11 (14)	C7—C9—H9C	109.5
C7—N1—C4	126.85 (14)	H9A—C9—H9C	109.5
C5—N1—C4	123.94 (14)	H9B—C9—H9C	109.5
C7—N2—C6	109.33 (14)	N2—C8—H8A	109.5
C7—N2—C8	125.87 (15)	N2—C8—H8B	109.5
C6—N2—C8	124.58 (15)	H8A—C8—H8B	109.5
C2—C1—C3ⁱ	120.51 (14)	N2—C8—H8C	109.5
C2—C1—H1	119.7	H8A—C8—H8C	109.5
C3ⁱ—C1—H1	119.7	H8B—C8—H8C	109.5
C1—C2—C3	120.79 (15)	C5—C6—N2	107.20 (15)
C1—C2—H2	119.6	C5—C6—H6	126.4
C3—C2—H2	119.6	N2—C6—H6	126.4
C2—C3—C1ⁱ	118.69 (15)	C6—C5—N1	107.02 (15)
C2—C3—C4	118.92 (14)	C6—C5—H5	126.5
C1ⁱ—C3—C4	122.36 (14)	N1—C5—H5	126.5
N1—C4—C3	112.68 (13)	F2—B1—F3	111.0 (3)
N1—C4—H4A	109.1	F2—B1—F4	107.7 (3)
C3—C4—H4A	109.1	F3—B1—F4	108.2 (3)
N1—C4—H4B	109.1	F2—B1—F1	110.5 (3)
C3—C4—H4B	109.1	F3—B1—F1	111.0 (3)
H4A—C4—H4B	107.8	F4—B1—F1	108.3 (3)
N2—C7—N1	107.34 (14)	F2'—B1'—F4'	110.1 (6)
N2—C7—C9	125.89 (15)	F2'—B1'—F1'	110.9 (6)
N1—C7—C9	126.76 (15)	F4'—B1'—F1'	110.0 (6)
C7—C9—H9A	109.5	F2'—B1'—F3'	108.4 (6)
C7—C9—H9B	109.5	F4'—B1'—F3'	108.0 (6)
H9A—C9—H9B	109.5	F1'—B1'—F3'	109.5 (6)

C3ⁱ—C1—C2—C3	−0.2 (3)	C8—N2—C7—C9	3.3 (3)
C1—C2—C3—C1ⁱ	0.2 (3)	C5—N1—C7—N2	1.03 (18)
C1—C2—C3—C4	−177.78 (15)	C4—N1—C7—N2	177.39 (14)
C7—N1—C4—C3	−104.65 (18)	C5—N1—C7—C9	−177.97 (17)
C5—N1—C4—C3	71.2 (2)	C4—N1—C7—C9	−1.6 (3)
C2—C3—C4—N1	−150.75 (15)	C7—N2—C6—C5	0.69 (19)
C1ⁱ—C3—C4—N1	31.3 (2)	C8—N2—C6—C5	175.47 (16)
C6—N2—C7—N1	−1.06 (18)	N2—C6—C5—N1	−0.05 (19)
C8—N2—C7—N1	−175.76 (15)	C7—N1—C5—C6	−0.61 (19)
C6—N2—C7—C9	177.95 (17)	C4—N1—C5—C6	−177.10 (15)

Symmetry code: (i) −x+1, −y+1, −z+1.

Experimental details

Crystal data
Chemical formula	C₁₈H₂₄N₄²⁺·2BF₄⁻
M_r	470.03
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	140
a, b, c (Å)	8.9095 (2), 10.2254 (2), 11.7113 (3)
β (°)	93.024 (1)
V (Å³)	1065.45 (4)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.14
Crystal size (mm)	0.40 × 0.35 × 0.05

Data collection
Diffractometer	Bruker SMART APEX diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.948, 0.993
No. of measured, independent and observed [I > 2σ(I)] reflections	7256, 2418, 2063
R_int	0.017
(sin θ/λ)_max (Å⁻¹)	0.650

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.047, 0.140, 1.03
No. of reflections	2418
No. of parameters	193
No. of restraints	124
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.42, −0.22

Computer programs: APEX2 (Bruker, 2008), SAINT (Bruker, 2008), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), X-SEED (Barbour, 2001), publCIF (Westrip, 2009).

Acknowledgements

We thank the University of Malaya (grant Nos. TA 0009/2008 A and FS343/2008 A) for supporting this study.

References

Barbour, L. J. (2001). J. Supramol. Chem. 1, 189–191. CrossRef CAS Google Scholar
Bruker (2008). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Ganesan, K., Alias, Y. & Ng, S. W. (2008). Acta Cryst. C64, o478–o480. Web of Science CSD CrossRef IUCr Journals Google Scholar
Sheldrick, G. M. (1996). SADABS. University of Göttingen, Germany. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Westrip, S. P. (2009). publCIF. In preparation. Google Scholar

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