3,3-Dimethyl-1,1-(propane-1,3-di­yl)diimidazol-1-ium tetra­bromido­cadmate(II)

Zhuang, L.; Zheng, C.; Wang, C.; Yuan, A.; Wang, G.

doi:10.1107/S1600536810031211

3,3-Dimethyl-1,1-(propane-1,3-diyl)diimidazol-1-ium tetrabromidocadmate(II)

L. Zhuang, C. Zheng, C. Wang, A. Yuan and G. Wang

The title compound, (C₁₁H₁₈N₄)[CdBr₄], was prepared by an anion exchange. The dihedral angle between the two planar imidazolium rings in the cation is 74.4 (4)°. The crystal packing is stabilized by weak intermolecular C—H

Br hydrogen bonds between the cation and the tetrahedral anion, building up a three-dimensionnal network.

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Supporting information

	Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536810031211/dn2593sup1.cif Contains datablocks global, I
	Structure factor file (CIF format) https://doi.org/10.1107/S1600536810031211/dn2593Isup2.hkl Contains datablock I

CCDC reference: 792258

checkCIF report

Key indicators

Single-crystal X-ray study
T = 293 K
Mean (C-C) = 0.019 Å
R factor = 0.062
wR factor = 0.144
Data-to-parameter ratio = 18.5

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT234_ALERT_4_B Large Hirshfeld Difference N3     --  C7      ..       0.25 Ang.

Alert level C
PLAT241_ALERT_2_C Check High      Ueq as Compared to Neighbors for         C7
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for         N1
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for         N4
PLAT342_ALERT_3_C Low Bond Precision on  C-C Bonds (x 1000) Ang ..         19
PLAT234_ALERT_4_C Large Hirshfeld Difference N2     --  C5      ..       0.16 Ang.
PLAT234_ALERT_4_C Large Hirshfeld Difference C5     --  C6      ..       0.19 Ang.
PLAT234_ALERT_4_C Large Hirshfeld Difference C6     --  C7      ..       0.21 Ang.
PLAT234_ALERT_4_C Large Hirshfeld Difference C8     --  C9      ..       0.21 Ang.
PLAT244_ALERT_4_C Low   'Solvent' Ueq as Compared to Neighbors of         Cd1

Alert level G
PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_G Check the Reported   _diffrn_ambient_temperature        293 K

   0 ALERT level A = In general: serious problem
   1 ALERT level B = Potentially serious problem
   9 ALERT level C = Check and explain
   2 ALERT level G = General alerts; check

   2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   3 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   6 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

Comment top

Ionic liquids (ILs) are generally formed by an organic cation and a weakly coordinating anion. They have enjoyed considerable research interests in recent years because of their unique properties such as high thermal stability, non-volatility, non-flammability, high ionic conductivity, wide electrochemical window and miscibility with organic compounds (Welton, 1999; Nicholas et al., 2004; Yu et al., 2007). Geminal dicationic ionic liquids have been shown to possess superior physical properties in terms of thermal stability and volatility compared to traditional ionic liquids (ILs) (Jared et al., 2005; Liang et al., 2008; Song et al., 2009). As part of our ongoing studies on new Geminal dicationic ionic liquids (Geng et al., 2010), we report here the crystal structure of the title compound (I).

In (I) (Fig. 1), the bond lengths and angles are within normal ranges (Allen et al., 1987). The two imidazolium rings are of course planar but make a dihedral angle of 74.4 (4)° which is much larger than the values reported for related compound as C₁₁H₁₈N_4.Br₂, 21.5° (Jared et al., 2005) or C₁₁H₁₈N_4.2PF₆ ,6.1 (2)°(Liang et al., 2008). The dication of the title structure has a highly twisted conformation with the two imidazolium rings almost perpendicular to the C₃ plane (angles of C5C6C7-N2C4N1C2C3 and C5C6C7-C8C9N4C10N3 are 79.4 (8)° and 86.1 (6)°, respectively), which are significantly lower than those observed in C₁₁H₁₈N_4.Br₂ (106.8 (7)° and 92.6 (6)°, respectively) (Jared et al., 2005).

Weak intermolecular C—H···Br hydrogen bonds between tetrabromide cadmium anions and imidazolium cations build up a three dimensionnal network. (Table 1, Fig.2).

Related literature top

For the properties and applications of ionic liquids, see: Welton (1999); Nicholas et al. (2004); Yu et al. (2007). For dicationic ionic liquids, see: Jared et al. (2005); Liang et al. (2008); Song et al. (2009); Geng et al. (2010). For related structures, see: Jared et al. (2005); Liang et al. (2008). For bond-length data, see: Allen et al. (1987).

Experimental top

A solution of 1,3-dibromide propane(10.1 g, 0.05 mol) in methanol(30 ml) was slowly added to a solution of 1-methylimidazole(9.4 g, 0.11 mol) in methanol(30 ml) at room temperature. The reaction mixture was then refluxed for 6 h. After evaporation of the solvent, the residue was washed with diethyl ether and dichloromethane, then dried in vacuum to obtain ionic liquid 3,3-dimethyl-1,1-(propane-1,3-diyl)- diimidazol-1-ium dibromide (a white solid ionic liquid).

A solution of above mentioned dibromide ionic liquid (3.66 g, 0.01 mol) in methanol(20 ml) was slowly added to a methanol solution of cadmium dibromide (3.44 g, 0.02 mol). The reaction mixture was stirred at room temperature for 3 h. After evaporation of the solvent, the residue was washed with methanol, then dried in vacuum to obtain title compound (I), 3,3-dimethyl-1,1-(propane-1,3-diyl)- diimidazol-1-ium tetrabromide cadmium(II)(yield 84%). M.p. 452–454 K.

Crystals of (I) suitable for X-ray diffraction were obtained by slow evaporation of methanol. ¹H NMR (DMSO, δ, p.p.m.) 8.82 (s, 2 H), 7.49 (d, 4 H), 4.37 (t, 4 H), 3.93 (s,6 H), 2.57 (t, 4 H).

Structure description top

Weak intermolecular C—H···Br hydrogen bonds between tetrabromide cadmium anions and imidazolium cations build up a three dimensionnal network. (Table 1, Fig.2).

Computing details top

Data collection: CAD-4 Software (Enraf–Nonius, 1989); cell refinement: CAD-4 Software (Enraf–Nonius, 1989); data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEPIII (Burnett & Johnson, 1996), ORTEP-3 for Windows (Farrugia, 1997) and PLATON (Spek, 2009); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top

	Fig. 1. A view of the molecular structure of (I) showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level. Hydrogen are represented as small spheres of arbitrary radii. Hydrogen bond is shown as dashed line.
	Fig. 2. Partial packing view showing the C-H···Br Hydrogen bonding pattern. Hydrogen bonds are drawn as dashed lines. H atoms not involved in hydrogen bonding have been omitted for clarity. [Symmetry codes : (i) -x+1, -y, -z+1; (ii) -x+1, y+1/2, -z+3/2; (iii) x-1, -y+1/2, z-1/2.

3,3-Dimethyl-1,1-(propane-1,3-diyl)diimidazol-1-ium tetrabromidocadmate(II) top

Crystal data top

(C₁₁H₁₈N₄)[CdBr₄]	F(000) = 1200
M_r = 638.33	D_x = 2.282 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 25 reflections
a = 8.5050 (17) Å	θ = 9–13°
b = 15.876 (3) Å	µ = 9.78 mm⁻¹
c = 13.836 (3) Å	T = 293 K
β = 96.07 (3)°	Block, white
V = 1857.7 (6) Å³	0.20 × 0.10 × 0.10 mm
Z = 4

Data collection top

Enraf–Nonius CAD-4 diffractometer	1874 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	R_int = 0.000
Graphite monochromator	θ_max = 25.3°, θ_min = 2.0°
ω/2θ scans	h = −10→10
Absorption correction: ψ scan (North et al., 1968)	k = 0→19
T_min = 0.245, T_max = 0.442	l = 0→16
3383 measured reflections	3 standard reflections every 200 reflections
3383 independent reflections	intensity decay: 1%

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)] = 0.062	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.144	H-atom parameters constrained
S = 0.95	w = 1/[σ²(F_o²) + (0.066P)²] where P = (F_o² + 2F_c²)/3
3383 reflections	(Δ/σ)_max < 0.001
183 parameters	Δρ_max = 0.72 e Å⁻³
0 restraints	Δρ_min = −0.77 e Å⁻³

Crystal data top

(C₁₁H₁₈N₄)[CdBr₄]	V = 1857.7 (6) Å³
M_r = 638.33	Z = 4
Monoclinic, P2₁/c	Mo Kα radiation
a = 8.5050 (17) Å	µ = 9.78 mm⁻¹
b = 15.876 (3) Å	T = 293 K
c = 13.836 (3) Å	0.20 × 0.10 × 0.10 mm
β = 96.07 (3)°

Data collection top

Enraf–Nonius CAD-4 diffractometer	1874 reflections with I > 2σ(I)
Absorption correction: ψ scan (North et al., 1968)	R_int = 0.000
T_min = 0.245, T_max = 0.442	3 standard reflections every 200 reflections
3383 measured reflections	intensity decay: 1%
3383 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.062	0 restraints
wR(F²) = 0.144	H-atom parameters constrained
S = 0.95	Δρ_max = 0.72 e Å⁻³
3383 reflections	Δρ_min = −0.77 e Å⁻³
183 parameters

Special details top

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 > 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) top

	x	y	z	U_iso*/U_eq
N1	0.2634 (10)	0.0761 (6)	0.4518 (6)	0.045 (2)
N2	0.2576 (10)	0.2095 (6)	0.4221 (7)	0.052 (2)
N3	0.5789 (10)	0.3667 (6)	0.6079 (7)	0.060 (3)
N4	0.8099 (10)	0.3936 (6)	0.6694 (6)	0.047 (2)
C1	0.2360 (16)	−0.0015 (9)	0.4950 (10)	0.095 (5)
H1A	0.2116	0.0075	0.5604	0.142*
H1B	0.3289	−0.0360	0.4959	0.142*
H1C	0.1488	−0.0293	0.4584	0.142*
C2	0.3518 (14)	0.0926 (9)	0.3730 (9)	0.066 (4)
H2A	0.4038	0.0519	0.3400	0.079*
C3	0.3505 (13)	0.1739 (8)	0.3527 (9)	0.064 (4)
H3A	0.3989	0.2014	0.3045	0.076*
C4	0.2128 (11)	0.1516 (8)	0.4794 (8)	0.050 (3)
H4A	0.1545	0.1609	0.5315	0.060*
C5	0.2341 (14)	0.3012 (8)	0.4287 (9)	0.068 (4)
H5A	0.1515	0.3121	0.4704	0.081*
H5B	0.1983	0.3228	0.3646	0.081*
C6	0.3818 (15)	0.3485 (8)	0.4682 (9)	0.074 (4)
H6A	0.4681	0.3349	0.4304	0.089*
H6B	0.3630	0.4087	0.4637	0.089*
C7	0.4240 (18)	0.3240 (9)	0.5717 (11)	0.096 (5)
H7A	0.4352	0.2634	0.5770	0.115*
H7B	0.3414	0.3416	0.6106	0.115*
C8	0.5739 (14)	0.4410 (8)	0.6537 (8)	0.057 (3)
H8A	0.4833	0.4729	0.6583	0.068*
C9	0.7154 (16)	0.4612 (8)	0.6906 (9)	0.067 (4)
H9A	0.7468	0.5103	0.7240	0.080*
C10	0.7192 (13)	0.3354 (8)	0.6172 (8)	0.055 (3)
H10A	0.7515	0.2842	0.5934	0.065*
C11	0.9894 (14)	0.3870 (10)	0.7007 (12)	0.107 (6)
H11A	1.0261	0.4384	0.7320	0.160*
H11B	1.0442	0.3778	0.6444	0.160*
H11C	1.0094	0.3408	0.7450	0.160*
Cd1	0.77770 (8)	0.15445 (5)	0.80145 (6)	0.0423 (2)
Br1	0.79089 (15)	0.29343 (8)	0.89683 (10)	0.0652 (4)
Br2	0.50899 (14)	0.13451 (8)	0.69780 (10)	0.0643 (4)
Br3	1.00029 (15)	0.14239 (11)	0.69122 (10)	0.0832 (5)
Br4	0.8109 (2)	0.04053 (11)	0.92709 (13)	0.1013 (6)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
N1	0.048 (6)	0.046 (6)	0.043 (5)	−0.003 (5)	0.011 (4)	−0.003 (4)
N2	0.040 (6)	0.056 (6)	0.061 (6)	0.011 (5)	0.004 (5)	−0.009 (5)
N3	0.046 (6)	0.034 (6)	0.092 (8)	−0.013 (4)	−0.031 (5)	0.002 (5)
N4	0.044 (5)	0.057 (6)	0.042 (5)	−0.002 (5)	0.010 (4)	0.021 (5)
C1	0.097 (11)	0.091 (11)	0.094 (11)	−0.056 (9)	0.004 (9)	0.006 (10)
C2	0.062 (9)	0.070 (9)	0.070 (9)	−0.008 (7)	0.029 (7)	−0.016 (7)
C3	0.054 (8)	0.077 (10)	0.063 (8)	−0.019 (7)	0.020 (6)	−0.018 (7)
C4	0.031 (6)	0.081 (9)	0.037 (6)	0.006 (6)	0.005 (5)	−0.009 (7)
C5	0.064 (9)	0.077 (10)	0.055 (8)	−0.001 (7)	−0.027 (6)	0.004 (7)
C6	0.094 (10)	0.073 (9)	0.056 (8)	0.005 (8)	0.009 (7)	0.000 (8)
C7	0.122 (14)	0.065 (10)	0.099 (12)	−0.021 (9)	0.005 (10)	−0.013 (8)
C8	0.054 (8)	0.062 (9)	0.052 (7)	0.002 (6)	−0.001 (6)	−0.003 (6)
C9	0.103 (11)	0.043 (7)	0.052 (7)	0.010 (8)	0.004 (7)	−0.009 (6)
C10	0.045 (7)	0.061 (8)	0.057 (7)	−0.006 (6)	0.001 (6)	0.015 (6)
C11	0.053 (9)	0.080 (11)	0.183 (18)	−0.017 (8)	−0.009 (10)	0.034 (11)
Cd1	0.0313 (4)	0.0491 (5)	0.0475 (5)	−0.0006 (4)	0.0080 (3)	−0.0051 (4)
Br1	0.0724 (9)	0.0536 (8)	0.0706 (9)	−0.0055 (6)	0.0119 (7)	−0.0081 (6)
Br2	0.0457 (7)	0.0684 (9)	0.0760 (9)	−0.0047 (6)	−0.0061 (6)	−0.0025 (7)
Br3	0.0583 (8)	0.1260 (14)	0.0684 (9)	0.0112 (9)	0.0214 (7)	−0.0020 (9)
Br4	0.1088 (13)	0.0956 (12)	0.1011 (12)	0.0178 (10)	0.0180 (10)	0.0049 (10)

Geometric parameters (Å, º) top

N1—C4	1.342 (13)	C5—C6	1.514 (16)
N1—C1	1.400 (15)	C5—H5A	0.9700
N1—C2	1.412 (13)	C5—H5B	0.9700
N2—C4	1.297 (13)	C6—C7	1.490 (17)
N2—C3	1.423 (14)	C6—H6A	0.9700
N2—C5	1.475 (15)	C6—H6B	0.9700
N3—C10	1.286 (13)	C7—H7A	0.9700
N3—C8	1.341 (14)	C7—H7B	0.9700
N3—C7	1.519 (15)	C8—C9	1.297 (15)
N4—C10	1.362 (13)	C8—H8A	0.9300
N4—C9	1.391 (13)	C9—H9A	0.9300
N4—C11	1.545 (14)	C10—H10A	0.9300
C1—H1A	0.9600	C11—H11A	0.9600
C1—H1B	0.9600	C11—H11B	0.9600
C1—H1C	0.9600	C11—H11C	0.9600
C2—C3	1.321 (17)	Cd1—Br4	2.5036 (19)
C2—H2A	0.9300	Cd1—Br3	2.5608 (16)
C3—H3A	0.9300	Cd1—Br1	2.5673 (15)
C4—H4A	0.9300	Cd1—Br2	2.5858 (16)

C4—N1—C1	126.2 (10)	C7—C6—C5	108.9 (11)
C4—N1—C2	105.5 (9)	C7—C6—H6A	109.9
C1—N1—C2	128.3 (11)	C5—C6—H6A	109.9
C4—N2—C3	110.5 (10)	C7—C6—H6B	109.9
C4—N2—C5	127.7 (11)	C5—C6—H6B	109.9
C3—N2—C5	121.5 (11)	H6A—C6—H6B	108.3
C10—N3—C8	111.6 (9)	C6—C7—N3	108.2 (11)
C10—N3—C7	128.6 (11)	C6—C7—H7A	110.0
C8—N3—C7	118.6 (11)	N3—C7—H7A	110.0
C10—N4—C9	109.1 (10)	C6—C7—H7B	110.0
C10—N4—C11	126.2 (11)	N3—C7—H7B	110.0
C9—N4—C11	124.7 (12)	H7A—C7—H7B	108.4
N1—C1—H1A	109.5	C9—C8—N3	109.2 (11)
N1—C1—H1B	109.5	C9—C8—H8A	125.4
H1A—C1—H1B	109.5	N3—C8—H8A	125.4
N1—C1—H1C	109.5	C8—C9—N4	105.0 (11)
H1A—C1—H1C	109.5	C8—C9—H9A	127.5
H1B—C1—H1C	109.5	N4—C9—H9A	127.5
C3—C2—N1	110.6 (11)	N3—C10—N4	105.0 (10)
C3—C2—H2A	124.7	N3—C10—H10A	127.5
N1—C2—H2A	124.7	N4—C10—H10A	127.5
C2—C3—N2	103.7 (11)	N4—C11—H11A	109.5
C2—C3—H3A	128.1	N4—C11—H11B	109.5
N2—C3—H3A	128.1	H11A—C11—H11B	109.5
N2—C4—N1	109.6 (9)	N4—C11—H11C	109.5
N2—C4—H4A	125.2	H11A—C11—H11C	109.5
N1—C4—H4A	125.2	H11B—C11—H11C	109.5
N2—C5—C6	113.6 (10)	Br4—Cd1—Br3	108.87 (6)
N2—C5—H5A	108.9	Br4—Cd1—Br1	105.57 (6)
C6—C5—H5A	108.9	Br3—Cd1—Br1	112.06 (6)
N2—C5—H5B	108.9	Br4—Cd1—Br2	108.95 (6)
C6—C5—H5B	108.9	Br3—Cd1—Br2	109.04 (6)
H5A—C5—H5B	107.7	Br1—Cd1—Br2	112.23 (5)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C7—H7A···Br2	0.97	2.67	3.515 (15)	145
C1—H1C···Br3ⁱ	0.96	2.93	3.819 (13)	155
C4—H4A···Br3ⁱⁱ	0.93	2.70	3.606 (11)	164
C5—H5B···Br3ⁱⁱⁱ	0.97	2.84	3.765 (11)	161
C8—H8A···Br4^iv	0.93	2.86	3.699 (12)	151

Symmetry codes: (i) −x+1, −y, −z+1; (ii) x−1, y, z; (iii) x−1, −y+1/2, z−1/2; (iv) −x+1, y+1/2, −z+3/2.

Experimental details

Crystal data
Chemical formula	(C₁₁H₁₈N₄)[CdBr₄]
M_r	638.33
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	293
a, b, c (Å)	8.5050 (17), 15.876 (3), 13.836 (3)
β (°)	96.07 (3)
V (Å³)	1857.7 (6)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	9.78
Crystal size (mm)	0.20 × 0.10 × 0.10

Data collection
Diffractometer	Enraf–Nonius CAD-4
Absorption correction	ψ scan (North et al., 1968)
T_min, T_max	0.245, 0.442
No. of measured, independent and observed [I > 2σ(I)] reflections	3383, 3383, 1874
R_int	0.000
(sin θ/λ)_max (Å⁻¹)	0.601

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.062, 0.144, 0.95
No. of reflections	3383
No. of parameters	183
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.72, −0.77

Computer programs: CAD-4 Software (Enraf–Nonius, 1989), XCAD4 (Harms & Wocadlo, 1995), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEPIII (Burnett & Johnson, 1996), ORTEP-3 for Windows (Farrugia, 1997) and PLATON (Spek, 2009).