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

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

doi:10.1107/S1600536809026324

organic compounds

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ISSN: 2056-9890

Volume 65| Part 8| August 2009| Page o1828

doi:10.1107/S1600536809026324

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

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⁺·2Br⁻, has the cation lying about a center of inversion. The five-membered imidazole ring is disordered over two positions with the major component having a site occupancy of 0.712 (4); the N-bound methyl substituents are ordered. The imidazole ring is approximately perpendicular to the six-membered phenylene ring [dihedral angle = 80.7 (5)° for the major disorder component and 89.8 (3)° for the other; the two components are off-set by 10.1 (6)°].

Related literature

For background to imidazolium-based ionic liquid salts, see: Ganesan et al. (2008 ). For 2,2′-dimethyl-3,3′-(p-phenylenedimethylene)diimidazol-1-ium dibromide, see: Dobrzańska (2005 ).

Experimental

Crystal data

C₁₈H₂₄N₄²⁺·2Br⁻
M_r = 456.23
Monoclinic, P 2₁ /n
a = 8.5689 (4) Å
b = 9.8617 (5) Å
c = 11.0272 (4) Å
β = 93.222 (3)°
V = 930.37 (7) Å³
Z = 2
Mo Kα radiation
μ = 4.36 mm⁻¹
T = 140 K
0.40 × 0.08 × 0.04 mm

Data collection

Bruker SMART APEX diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ) T_min = 0.274, T_max = 0.845
5882 measured reflections
2131 independent reflections
1575 reflections with I > 2σ(I)
R_int = 0.051

Refinement

R[F² > 2σ(F²)] = 0.039
wR(F²) = 0.096
S = 1.04
2131 reflections
112 parameters
36 restraints
H-atom parameters constrained
Δρ_max = 0.54 e Å⁻³
Δρ_min = −0.99 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/S1600536809026324/tk2494sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809026324/tk2494Isup2.hkl

checkCIF report

Related literature top

For background to imidazolium-based ionic liquid salts, see: Ganesan et al. (2008). For 2,2'-dimethyl-3,3'-(p-phenylenedimethylene)diimidazol-1-ium dibromide, see: Dobrzańska (2005).

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.

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⁺ 2Br^- at the 70% probability level; hydrogen atoms are drawn as spheres of arbitrary radius. The imidazolyl ring 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, -y, -z.

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

Crystal data top

C₁₈H₂₄N₄²⁺·2Br⁻	F(000) = 460
M_r = 456.23	D_x = 1.629 Mg m⁻³
Monoclinic, P2₁/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 1543 reflections
a = 8.5689 (4) Å	θ = 2.8–25.5°
b = 9.8617 (5) Å	µ = 4.36 mm⁻¹
c = 11.0272 (4) Å	T = 140 K
β = 93.222 (3)°	Prism, colorless
V = 930.37 (7) Å³	0.40 × 0.08 × 0.04 mm
Z = 2

Data collection top

Bruker SMART APEX diffractometer	2131 independent reflections
Radiation source: fine-focus sealed tube	1575 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.051
ω scans	θ_max = 27.5°, θ_min = 2.8°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −11→10
T_min = 0.274, T_max = 0.845	k = −12→12
5882 measured reflections	l = −14→14

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)] = 0.039	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.096	H-atom parameters constrained
S = 1.04	w = 1/[σ²(F_o²) + (0.0403P)² + 0.5004P] where P = (F_o² + 2F_c²)/3
2131 reflections	(Δ/σ)_max = 0.001
112 parameters	Δρ_max = 0.54 e Å⁻³
36 restraints	Δρ_min = −0.99 e Å⁻³

Crystal data top

C₁₈H₂₄N₄²⁺·2Br⁻	V = 930.37 (7) Å³
M_r = 456.23	Z = 2
Monoclinic, P2₁/n	Mo Kα radiation
a = 8.5689 (4) Å	µ = 4.36 mm⁻¹
b = 9.8617 (5) Å	T = 140 K
c = 11.0272 (4) Å	0.40 × 0.08 × 0.04 mm
β = 93.222 (3)°

Data collection top

Bruker SMART APEX diffractometer	2131 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	1575 reflections with I > 2σ(I)
T_min = 0.274, T_max = 0.845	R_int = 0.051
5882 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.039	36 restraints
wR(F²) = 0.096	H-atom parameters constrained
S = 1.04	Δρ_max = 0.54 e Å⁻³
2131 reflections	Δρ_min = −0.99 e Å⁻³
112 parameters

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

	x	y	z	U_iso*/U_eq	Occ. (<1)
Br1	0.46792 (4)	0.59691 (4)	0.76873 (3)	0.02742 (14)
C1	0.6432 (4)	0.0488 (4)	0.4669 (3)	0.0194 (7)
H1	0.7414	0.0823	0.4445	0.023*
C2	0.6148 (4)	0.0331 (3)	0.5895 (3)	0.0194 (7)
H2	0.6936	0.0558	0.6501	0.023*
C3	0.4712 (4)	−0.0158 (3)	0.6230 (3)	0.0188 (7)
C4	0.4343 (4)	−0.0353 (4)	0.7539 (3)	0.0201 (7)
H4A	0.3204	−0.0246	0.7615	0.024*	0.712 (4)
H4B	0.4631	−0.1287	0.7794	0.024*	0.712 (4)
H4C	0.4003	−0.1303	0.7649	0.024*	0.288 (4)
H4D	0.3452	0.0241	0.7714	0.024*	0.288 (4)
N1	0.5158 (3)	0.0594 (3)	0.8328 (3)	0.0199 (10)	0.712 (4)
C5	0.4760 (4)	0.1910 (3)	0.8444 (3)	0.0259 (11)	0.712 (4)
H5	0.3862	0.2336	0.8072	0.031*	0.712 (4)
C6	0.5862 (4)	0.2513 (2)	0.9182 (3)	0.0270 (13)	0.712 (4)
H6	0.5875	0.3439	0.9421	0.032*	0.712 (4)
N2	0.6941 (3)	0.1570 (3)	0.9523 (3)	0.0207 (9)	0.712 (4)
C7	0.6507 (4)	0.0384 (2)	0.8994 (3)	0.0203 (11)	0.712 (4)
C8	0.7408 (7)	−0.0908 (5)	0.9105 (5)	0.0256 (12)	0.712 (4)
H8A	0.8262	−0.0889	0.8549	0.038*	0.712 (4)
H8B	0.6714	−0.1673	0.8896	0.038*	0.712 (4)
H8C	0.7842	−0.1012	0.9941	0.038*	0.712 (4)
N1'	0.5677 (9)	−0.0057 (8)	0.8456 (6)	0.0199 (10)	0.288
C5'	0.6581 (11)	−0.1058 (6)	0.8950 (8)	0.0259 (11)	0.288
H5'	0.6480	−0.1998	0.8775	0.031*	0.288 (4)
C6'	0.7654 (9)	−0.0488 (8)	0.9736 (8)	0.0270 (13)	0.288
H6'	0.8440	−0.0956	1.0211	0.032*	0.288 (4)
N2'	0.7413 (9)	0.0865 (7)	0.9728 (7)	0.0207 (9)	0.288
C7'	0.6192 (10)	0.1132 (6)	0.8937 (7)	0.0203 (11)	0.288
C8'	0.5509 (19)	0.2515 (14)	0.8644 (14)	0.0256 (12)	0.288
H8'1	0.5473	0.3048	0.9392	0.038*	0.288 (4)
H8'2	0.4448	0.2412	0.8275	0.038*	0.288 (4)
H8'3	0.6162	0.2983	0.8074	0.038*	0.288 (4)
C9	0.8342 (5)	0.1840 (4)	1.0313 (3)	0.0293 (9)
H9A	0.8278	0.2755	1.0654	0.044*	0.712 (4)
H9B	0.9272	0.1770	0.9840	0.044*	0.712 (4)
H9C	0.8410	0.1175	1.0975	0.044*	0.712 (4)
H9D	0.7798	0.2715	1.0279	0.044*	0.288 (4)
H9E	0.9330	0.1919	0.9912	0.044*	0.288 (4)
H9F	0.8555	0.1577	1.1164	0.044*	0.288 (4)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Br1	0.0221 (2)	0.0266 (2)	0.0336 (2)	0.00039 (17)	0.00258 (14)	−0.00512 (16)
C1	0.0122 (19)	0.0253 (17)	0.0208 (17)	−0.0017 (14)	0.0021 (13)	0.0009 (13)
C2	0.016 (2)	0.0235 (18)	0.0183 (17)	0.0002 (14)	−0.0025 (13)	−0.0002 (13)
C3	0.019 (2)	0.0188 (17)	0.0192 (17)	0.0022 (14)	0.0025 (13)	0.0007 (13)
C4	0.013 (2)	0.0275 (18)	0.0194 (17)	−0.0009 (14)	−0.0008 (13)	0.0010 (13)
N1	0.018 (2)	0.025 (2)	0.0168 (18)	−0.0023 (17)	0.0016 (16)	0.0014 (17)
C5	0.025 (3)	0.030 (3)	0.022 (2)	0.008 (2)	0.000 (2)	0.000 (2)
C6	0.027 (3)	0.026 (3)	0.028 (3)	0.006 (2)	0.000 (2)	0.002 (2)
N2	0.020 (3)	0.025 (2)	0.0164 (19)	−0.0032 (18)	0.0019 (16)	0.0007 (17)
C7	0.018 (3)	0.023 (3)	0.021 (2)	0.000 (2)	0.0055 (18)	0.005 (2)
C8	0.021 (3)	0.021 (2)	0.034 (3)	0.009 (2)	0.000 (2)	0.012 (2)
N1'	0.018 (2)	0.025 (2)	0.0168 (18)	−0.0023 (17)	0.0016 (16)	0.0014 (17)
C5'	0.025 (3)	0.030 (3)	0.022 (2)	0.008 (2)	0.000 (2)	0.000 (2)
C6'	0.027 (3)	0.026 (3)	0.028 (3)	0.006 (2)	0.000 (2)	0.002 (2)
N2'	0.020 (3)	0.025 (2)	0.0164 (19)	−0.0032 (18)	0.0019 (16)	0.0007 (17)
C7'	0.018 (3)	0.023 (3)	0.021 (2)	0.000 (2)	0.0055 (18)	0.005 (2)
C8'	0.021 (3)	0.021 (2)	0.034 (3)	0.009 (2)	0.000 (2)	0.012 (2)
C9	0.025 (2)	0.034 (2)	0.027 (2)	−0.0067 (17)	−0.0061 (16)	0.0026 (16)

Geometric parameters (Å, º) top

C1—C3ⁱ	1.392 (5)	C8—H8A	0.9800
C1—C2	1.396 (4)	C8—H8B	0.9800
C1—H1	0.9500	C8—H8C	0.9800
C2—C3	1.391 (5)	N1'—C5'	1.3500
C2—H2	0.9500	N1'—C7'	1.3500
C3—C1ⁱ	1.392 (5)	C5'—C6'	1.3500
C3—C4	1.507 (4)	C5'—H5'	0.9500
C4—N1	1.432 (4)	C6'—N2'	1.3500
C4—N1'	1.512 (7)	C6'—H6'	0.9500
C4—H4A	0.9900	N2'—C7'	1.3500
C4—H4B	0.9900	N2'—C9	1.384 (7)
C4—H4C	0.9900	C7'—C8'	1.513 (15)
C4—H4D	0.9900	C8'—H8'1	0.9800
N1—C5	1.3500	C8'—H8'2	0.9800
N1—C7	1.3500	C8'—H8'3	0.9800
C5—C6	1.3500	C9—H9A	0.9800
C5—H5	0.9500	C9—H9B	0.9800
C6—N2	1.3500	C9—H9C	0.9800
C6—H6	0.9500	C9—H9D	0.9800
N2—C7	1.3500	C9—H9E	0.9800
N2—C9	1.468 (4)	C9—H9F	0.9800
C7—C8	1.492 (5)

C3ⁱ—C1—C2	120.6 (3)	N2—C7—C8	125.2 (3)
C3ⁱ—C1—H1	119.7	N1—C7—C8	126.8 (3)
C2—C1—H1	119.7	C5'—N1'—C7'	108.0
C3—C2—C1	120.1 (3)	C5'—N1'—C4	121.6 (6)
C3—C2—H2	120.0	C7'—N1'—C4	130.4 (6)
C1—C2—H2	120.0	C6'—C5'—N1'	108.0
C2—C3—C1ⁱ	119.3 (3)	C6'—C5'—H5'	126.0
C2—C3—C4	122.4 (3)	N1'—C5'—H5'	126.0
C1ⁱ—C3—C4	118.3 (3)	C5'—C6'—N2'	108.0
N1—C4—C3	112.1 (3)	C5'—C6'—H6'	126.0
C3—C4—N1'	115.1 (4)	N2'—C6'—H6'	126.0
N1—C4—H4A	109.2	C7'—N2'—C6'	108.0
C3—C4—H4A	109.2	C7'—N2'—C9	124.8 (6)
N1'—C4—H4A	129.4	C6'—N2'—C9	126.8 (6)
N1—C4—H4B	109.2	N2'—C7'—N1'	108.0
C3—C4—H4B	109.2	N2'—C7'—C8'	126.2 (8)
H4A—C4—H4B	107.9	N1'—C7'—C8'	125.8 (8)
C3—C4—H4C	108.5	C7'—C8'—H8'1	109.5
N1'—C4—H4C	108.5	C7'—C8'—H8'2	109.5
C3—C4—H4D	108.5	H8'1—C8'—H8'2	109.5
N1'—C4—H4D	108.5	C7'—C8'—H8'3	109.5
H4C—C4—H4D	107.5	H8'1—C8'—H8'3	109.5
C5—N1—C7	108.0	H8'2—C8'—H8'3	109.5
C5—N1—C4	124.6 (3)	N2—C9—H9A	109.5
C7—N1—C4	127.2 (3)	N2—C9—H9B	109.5
N1—C5—C6	108.0	H9A—C9—H9B	109.5
N1—C5—H5	126.0	N2—C9—H9C	109.5
C6—C5—H5	126.0	H9A—C9—H9C	109.5
N2—C6—C5	108.0	H9B—C9—H9C	109.5
N2—C6—H6	126.0	N2'—C9—H9D	109.5
C5—C6—H6	126.0	N2'—C9—H9E	109.5
C6—N2—C7	108.0	H9D—C9—H9E	109.5
C6—N2—C9	124.4 (3)	N2'—C9—H9F	109.5
C7—N2—C9	127.6 (3)	H9D—C9—H9F	109.5
N2—C7—N1	108.0	H9E—C9—H9F	109.5

C3ⁱ—C1—C2—C3	−0.1 (6)	C4—N1—C7—C8	−3.3 (5)
C1—C2—C3—C1ⁱ	0.1 (6)	N1—C4—N1'—C5'	170.1 (11)
C1—C2—C3—C4	179.8 (3)	C3—C4—N1'—C5'	−98.3 (6)
C2—C3—C4—N1	30.3 (5)	N1—C4—N1'—C7'	−9.2 (5)
C1ⁱ—C3—C4—N1	−150.0 (3)	C3—C4—N1'—C7'	82.4 (8)
C2—C3—C4—N1'	−3.4 (6)	C7'—N1'—C5'—C6'	0.0
C1ⁱ—C3—C4—N1'	176.3 (4)	C4—N1'—C5'—C6'	−179.5 (8)
C3—C4—N1—C5	76.5 (4)	N1'—C5'—C6'—N2'	0.0
N1'—C4—N1—C5	178.8 (8)	C5'—C6'—N2'—C7'	0.0
C3—C4—N1—C7	−97.3 (3)	C5'—C6'—N2'—C9	−173.4 (8)
N1'—C4—N1—C7	4.9 (7)	C6'—N2'—C7'—N1'	0.0
C7—N1—C5—C6	0.0	C9—N2'—C7'—N1'	173.5 (8)
C4—N1—C5—C6	−174.8 (3)	C6'—N2'—C7'—C8'	179.7 (11)
N1—C5—C6—N2	0.0	C9—N2'—C7'—C8'	−6.8 (12)
C5—C6—N2—C7	0.0	C5'—N1'—C7'—N2'	0.0
C5—C6—N2—C9	179.0 (3)	C4—N1'—C7'—N2'	179.4 (8)
C6—N2—C7—N1	0.0	C5'—N1'—C7'—C8'	−179.7 (11)
C9—N2—C7—N1	−179.0 (4)	C4—N1'—C7'—C8'	−0.3 (12)
C6—N2—C7—C8	178.0 (4)	C7'—N2'—C9—N2	6.6 (5)
C9—N2—C7—C8	−1.0 (5)	C6'—N2'—C9—N2	179.0 (11)
C5—N1—C7—N2	0.0	C6—N2—C9—N2'	171.4 (8)
C4—N1—C7—N2	174.7 (3)	C7—N2—C9—N2'	−9.8 (7)
C5—N1—C7—C8	−177.9 (4)

Symmetry code: (i) −x+1, −y, −z+1.

Experimental details

Crystal data
Chemical formula	C₁₈H₂₄N₄²⁺·2Br⁻
M_r	456.23
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	140
a, b, c (Å)	8.5689 (4), 9.8617 (5), 11.0272 (4)
β (°)	93.222 (3)
V (Å³)	930.37 (7)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	4.36
Crystal size (mm)	0.40 × 0.08 × 0.04

Data collection
Diffractometer	Bruker SMART APEX diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.274, 0.845
No. of measured, independent and observed [I > 2σ(I)] reflections	5882, 2131, 1575
R_int	0.051
(sin θ/λ)_max (Å⁻¹)	0.650

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.039, 0.096, 1.04
No. of reflections	2131
No. of parameters	112
No. of restraints	36
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.54, −0.99

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

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