organic compounds
3,3′-Dibenzyl-1,1′-(2,4,6-trimethyl-m-phenylenedimethylene)diimidazol-3-ium dibromide
aSchool of Chemical Sciences, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia, and bX-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia
*Correspondence e-mail: hkfun@usm.my
In the title molecular salt, C31H34N42+·2Br−, the central benzene ring makes dihedral angles of 80.47 (12) and 82.78 (12)° with the adjacent imidazole rings. The dihedral angle between the two terminal phenyl rings is 79.16 (13)°. In the crystal, the cations and anions are linked via C—H⋯Br hydrogen bonds, forming supramolecular chains along the c axis.
Related literature
For applications of N-heterocyclic (NHCs), see: Winkelmann & Navarro (2010); Papini et al. (2008); Marion et al. (2007); Burstein & Glorius (2004); Sohn et al. (2004); Grasa et al. (2002); Singh & Nolan (2005). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986).
Experimental
Crystal data
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Refinement
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Data collection: APEX2 (Bruker, 2009); cell SAINT (Bruker, 2009); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009).
Supporting information
10.1107/S1600536811005204/wn2422sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536811005204/wn2422Isup2.hkl
A mixture of imidazole (1.0 g, 14.0 mmol) and sodium hydroxide (0.6 g, 15.0 mmol) in DMSO (20 ml) was heated to 363 K for 2 h. The mixture was cooled at room temperature then 1,3-bis(bromomethyl)mesitylene (2.0 g, 6.5 mmol) in 10 ml of DMSO was added, heated to 413 K for 1 h and poured into water (200 ml), then cooled in an ice bath. The resulting precipitate was collected by filtration, washed with water (3x10 ml), and recrystallised from methanol/water to give 1,3-bis(N-imidazole-1-ylmethyl)mesitylene as an off-white solid (1.45 g, 79 %). Further, a mixture of 1,3-bis(N-imidazole-1-ylmethyl)mesitylene (0.7 g, 2.5 mmol) and benzyl bromide (1.0 g, 5.8 mmol) in 30 ml of acetonitrile, was refluxed for 24 h, then cooled to room temperature and left standing overnight, giving the title compound as light brown crystals which were isolated by decantation and washed with diethyl ether (2x5 ml) and placed in a desiccator. The yield was (1.15 g, 74%). The resulting crystals were suitable for X-ray diffraction.
All H atoms were positioned geometrically [C–H = 0.93–0.97 Å] and were refined using a riding model, with Uiso(H) = xUeq(C), where x = 1.5 for methyl H and 1.2 for all other H atoms. The highest peak in the final difference map was found at a distance of 0.77 Å from Br1.
Data collection: APEX2 (Bruker, 2009); cell
SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).Fig. 1. The asymmetric unit of the title compound, showing 30% probability displacement ellipsoids. H atoms have been omitted for clarity. | |
Fig. 2. The crystal packing of the title compound, showing hydrogen-bonded (dashed lines) one-dimensional supramolecular chains along the c-axis. |
C31H34N42+·2Br− | F(000) = 1272 |
Mr = 622.44 | Dx = 1.436 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 9955 reflections |
a = 8.9851 (2) Å | θ = 2.3–29.9° |
b = 12.8044 (2) Å | µ = 2.84 mm−1 |
c = 25.6419 (5) Å | T = 100 K |
β = 102.611 (1)° | Plate, colourless |
V = 2878.90 (10) Å3 | 0.49 × 0.43 × 0.21 mm |
Z = 4 |
Bruker SMART APEXII CCD area-detector diffractometer | 8490 independent reflections |
Radiation source: fine-focus sealed tube | 6550 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.036 |
ϕ and ω scans | θmax = 30.2°, θmin = 2.3° |
Absorption correction: multi-scan (SADABS; Bruker, 2009) | h = −12→12 |
Tmin = 0.337, Tmax = 0.585 | k = −17→18 |
32884 measured reflections | l = −30→36 |
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)] = 0.040 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.101 | H-atom parameters constrained |
S = 1.04 | w = 1/[σ2(Fo2) + (0.0549P)2 + 0.6972P] where P = (Fo2 + 2Fc2)/3 |
8490 reflections | (Δ/σ)max = 0.003 |
337 parameters | Δρmax = 1.28 e Å−3 |
0 restraints | Δρmin = −0.40 e Å−3 |
C31H34N42+·2Br− | V = 2878.90 (10) Å3 |
Mr = 622.44 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 8.9851 (2) Å | µ = 2.84 mm−1 |
b = 12.8044 (2) Å | T = 100 K |
c = 25.6419 (5) Å | 0.49 × 0.43 × 0.21 mm |
β = 102.611 (1)° |
Bruker SMART APEXII CCD area-detector diffractometer | 8490 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2009) | 6550 reflections with I > 2σ(I) |
Tmin = 0.337, Tmax = 0.585 | Rint = 0.036 |
32884 measured reflections |
R[F2 > 2σ(F2)] = 0.040 | 0 restraints |
wR(F2) = 0.101 | H-atom parameters constrained |
S = 1.04 | Δρmax = 1.28 e Å−3 |
8490 reflections | Δρmin = −0.40 e Å−3 |
337 parameters |
Experimental. The crystal was placed in the cold stream of an Oxford Cryosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) K. |
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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. |
x | y | z | Uiso*/Ueq | ||
N1 | 0.6565 (2) | 0.78480 (15) | 0.80723 (7) | 0.0240 (4) | |
N2 | 0.4998 (2) | 0.82215 (14) | 0.85747 (8) | 0.0235 (4) | |
N3 | 0.9596 (2) | 0.88648 (15) | 1.09775 (8) | 0.0244 (4) | |
N4 | 1.1823 (2) | 0.82656 (14) | 1.09554 (8) | 0.0242 (4) | |
C1 | 0.9744 (3) | 0.8645 (3) | 0.74204 (12) | 0.0452 (7) | |
H1A | 1.0412 | 0.8088 | 0.7517 | 0.054* | |
C2 | 1.0150 (4) | 0.9467 (3) | 0.71276 (14) | 0.0591 (9) | |
H2A | 1.1091 | 0.9461 | 0.7033 | 0.071* | |
C3 | 0.9160 (4) | 1.0297 (3) | 0.69757 (12) | 0.0504 (8) | |
H3A | 0.9425 | 1.0845 | 0.6776 | 0.060* | |
C4 | 0.7775 (3) | 1.0297 (2) | 0.71252 (11) | 0.0395 (6) | |
H4A | 0.7102 | 1.0850 | 0.7024 | 0.047* | |
C5 | 0.7372 (3) | 0.94820 (19) | 0.74249 (10) | 0.0309 (5) | |
H5A | 0.6441 | 0.9499 | 0.7527 | 0.037* | |
C6 | 0.8349 (3) | 0.86441 (19) | 0.75719 (9) | 0.0274 (5) | |
C7 | 0.7989 (3) | 0.77211 (19) | 0.78865 (9) | 0.0268 (5) | |
H7A | 0.7912 | 0.7101 | 0.7665 | 0.032* | |
H7B | 0.8822 | 0.7616 | 0.8193 | 0.032* | |
C8 | 0.5118 (3) | 0.76704 (19) | 0.77738 (10) | 0.0292 (5) | |
H8A | 0.4861 | 0.7428 | 0.7424 | 0.035* | |
C9 | 0.4139 (3) | 0.79170 (19) | 0.80890 (10) | 0.0298 (5) | |
H9A | 0.3080 | 0.7886 | 0.7993 | 0.036* | |
C10 | 0.6473 (2) | 0.81899 (16) | 0.85554 (9) | 0.0216 (4) | |
H10A | 0.7289 | 0.8374 | 0.8830 | 0.026* | |
C11 | 0.4391 (2) | 0.85726 (18) | 0.90348 (9) | 0.0248 (4) | |
H11A | 0.3343 | 0.8340 | 0.8989 | 0.030* | |
H11B | 0.4393 | 0.9330 | 0.9046 | 0.030* | |
C12 | 0.5310 (2) | 0.81582 (16) | 0.95579 (9) | 0.0226 (4) | |
C13 | 0.6366 (2) | 0.87950 (16) | 0.98984 (9) | 0.0225 (4) | |
C14 | 0.7047 (2) | 0.84395 (17) | 1.04123 (9) | 0.0236 (4) | |
C15 | 0.6774 (3) | 0.74111 (18) | 1.05665 (9) | 0.0261 (5) | |
C16 | 0.5809 (3) | 0.67784 (17) | 1.02034 (10) | 0.0272 (5) | |
H16A | 0.5668 | 0.6090 | 1.0298 | 0.033* | |
C17 | 0.5045 (2) | 0.71272 (17) | 0.97056 (9) | 0.0249 (5) | |
C18 | 0.7980 (3) | 0.91657 (17) | 1.08167 (10) | 0.0269 (5) | |
H18A | 0.7914 | 0.9865 | 1.0668 | 0.032* | |
H18B | 0.7547 | 0.9183 | 1.1132 | 0.032* | |
C19 | 1.0401 (2) | 0.83681 (17) | 1.06739 (9) | 0.0236 (4) | |
H19A | 1.0032 | 0.8134 | 1.0326 | 0.028* | |
C20 | 1.0534 (3) | 0.90914 (19) | 1.14621 (10) | 0.0322 (5) | |
H20A | 1.0258 | 0.9440 | 1.1745 | 0.039* | |
C21 | 1.1933 (3) | 0.87145 (19) | 1.14526 (10) | 0.0315 (5) | |
H21A | 1.2800 | 0.8750 | 1.1727 | 0.038* | |
C22 | 1.3042 (3) | 0.76808 (17) | 1.07770 (10) | 0.0268 (5) | |
H22A | 1.4030 | 0.7916 | 1.0976 | 0.032* | |
H22B | 1.2985 | 0.7816 | 1.0401 | 0.032* | |
C23 | 1.2878 (2) | 0.65205 (18) | 1.08634 (9) | 0.0236 (4) | |
C24 | 1.1996 (3) | 0.59206 (19) | 1.04611 (10) | 0.0307 (5) | |
H24A | 1.1554 | 0.6224 | 1.0134 | 0.037* | |
C25 | 1.1774 (3) | 0.4869 (2) | 1.05463 (12) | 0.0395 (6) | |
H25A | 1.1199 | 0.4464 | 1.0274 | 0.047* | |
C26 | 1.2404 (3) | 0.44214 (19) | 1.10336 (12) | 0.0385 (6) | |
H26A | 1.2218 | 0.3723 | 1.1095 | 0.046* | |
C27 | 1.3312 (3) | 0.5008 (2) | 1.14307 (11) | 0.0360 (6) | |
H27A | 1.3760 | 0.4701 | 1.1756 | 0.043* | |
C28 | 1.3553 (3) | 0.6056 (2) | 1.13442 (10) | 0.0304 (5) | |
H28A | 1.4171 | 0.6450 | 1.1611 | 0.036* | |
C29 | 0.6784 (3) | 0.98590 (17) | 0.97157 (10) | 0.0263 (5) | |
H29A | 0.7857 | 0.9975 | 0.9843 | 0.039* | |
H29B | 0.6224 | 1.0388 | 0.9856 | 0.039* | |
H29C | 0.6535 | 0.9888 | 0.9332 | 0.039* | |
C30 | 0.3955 (3) | 0.64136 (19) | 0.93407 (11) | 0.0315 (5) | |
H30A | 0.3917 | 0.5752 | 0.9513 | 0.047* | |
H30B | 0.4297 | 0.6314 | 0.9015 | 0.047* | |
H30C | 0.2956 | 0.6721 | 0.9262 | 0.047* | |
C31 | 0.7495 (3) | 0.69928 (19) | 1.11128 (10) | 0.0336 (5) | |
H31A | 0.7026 | 0.6341 | 1.1168 | 0.050* | |
H31B | 0.7352 | 0.7485 | 1.1380 | 0.050* | |
H31C | 0.8566 | 0.6887 | 1.1138 | 0.050* | |
Br1 | 0.03325 (2) | 0.815324 (18) | 0.928724 (9) | 0.02679 (7) | |
Br2 | 0.59309 (3) | 0.572410 (19) | 0.692096 (9) | 0.03010 (7) |
U11 | U22 | U33 | U12 | U13 | U23 | |
N1 | 0.0227 (9) | 0.0246 (9) | 0.0250 (9) | 0.0029 (7) | 0.0060 (7) | −0.0007 (7) |
N2 | 0.0216 (9) | 0.0207 (9) | 0.0288 (10) | 0.0030 (7) | 0.0070 (7) | 0.0024 (7) |
N3 | 0.0271 (9) | 0.0217 (9) | 0.0264 (10) | 0.0038 (7) | 0.0100 (7) | 0.0010 (8) |
N4 | 0.0245 (9) | 0.0191 (9) | 0.0306 (10) | 0.0010 (7) | 0.0095 (7) | 0.0012 (7) |
C1 | 0.0230 (12) | 0.066 (2) | 0.0476 (16) | −0.0013 (13) | 0.0093 (11) | 0.0009 (15) |
C2 | 0.0332 (15) | 0.089 (3) | 0.060 (2) | −0.0205 (16) | 0.0208 (14) | 0.0009 (19) |
C3 | 0.0549 (19) | 0.0547 (19) | 0.0431 (17) | −0.0281 (16) | 0.0142 (14) | −0.0028 (14) |
C4 | 0.0529 (17) | 0.0309 (14) | 0.0354 (14) | −0.0077 (12) | 0.0111 (12) | −0.0017 (11) |
C5 | 0.0350 (13) | 0.0304 (13) | 0.0296 (12) | −0.0032 (10) | 0.0118 (10) | −0.0056 (10) |
C6 | 0.0244 (11) | 0.0336 (13) | 0.0242 (11) | −0.0037 (9) | 0.0050 (9) | −0.0073 (9) |
C7 | 0.0245 (11) | 0.0302 (12) | 0.0265 (11) | 0.0061 (9) | 0.0071 (9) | −0.0041 (9) |
C8 | 0.0279 (11) | 0.0306 (13) | 0.0274 (12) | −0.0010 (9) | 0.0025 (9) | −0.0031 (10) |
C9 | 0.0224 (11) | 0.0298 (12) | 0.0361 (13) | −0.0006 (9) | 0.0038 (9) | −0.0004 (10) |
C10 | 0.0224 (10) | 0.0192 (10) | 0.0234 (10) | 0.0019 (8) | 0.0055 (8) | 0.0009 (8) |
C11 | 0.0228 (10) | 0.0236 (11) | 0.0307 (12) | 0.0053 (8) | 0.0119 (9) | 0.0026 (9) |
C12 | 0.0235 (10) | 0.0201 (10) | 0.0281 (11) | 0.0066 (8) | 0.0140 (8) | 0.0039 (9) |
C13 | 0.0243 (10) | 0.0171 (10) | 0.0311 (12) | 0.0048 (8) | 0.0167 (9) | 0.0025 (8) |
C14 | 0.0226 (10) | 0.0220 (11) | 0.0304 (12) | 0.0052 (8) | 0.0149 (9) | 0.0035 (9) |
C15 | 0.0272 (11) | 0.0234 (11) | 0.0316 (12) | 0.0078 (9) | 0.0152 (9) | 0.0069 (9) |
C16 | 0.0326 (12) | 0.0173 (11) | 0.0361 (13) | 0.0053 (9) | 0.0171 (10) | 0.0052 (9) |
C17 | 0.0248 (10) | 0.0186 (10) | 0.0356 (12) | 0.0029 (8) | 0.0160 (9) | 0.0003 (9) |
C18 | 0.0278 (11) | 0.0222 (11) | 0.0339 (12) | 0.0064 (9) | 0.0136 (9) | 0.0017 (9) |
C19 | 0.0256 (11) | 0.0205 (11) | 0.0267 (11) | 0.0010 (8) | 0.0102 (9) | 0.0015 (8) |
C20 | 0.0388 (13) | 0.0311 (13) | 0.0274 (12) | 0.0054 (10) | 0.0089 (10) | −0.0037 (10) |
C21 | 0.0336 (13) | 0.0279 (13) | 0.0314 (13) | 0.0051 (10) | 0.0032 (10) | −0.0044 (10) |
C22 | 0.0230 (10) | 0.0221 (11) | 0.0386 (13) | 0.0011 (8) | 0.0138 (9) | 0.0012 (9) |
C23 | 0.0212 (10) | 0.0224 (11) | 0.0296 (11) | 0.0034 (8) | 0.0106 (8) | 0.0024 (9) |
C24 | 0.0291 (12) | 0.0268 (12) | 0.0345 (13) | 0.0019 (9) | 0.0031 (10) | 0.0031 (10) |
C25 | 0.0333 (13) | 0.0279 (13) | 0.0540 (17) | −0.0006 (10) | 0.0022 (12) | −0.0048 (12) |
C26 | 0.0368 (14) | 0.0186 (12) | 0.0631 (19) | 0.0061 (10) | 0.0175 (13) | 0.0087 (11) |
C27 | 0.0382 (14) | 0.0359 (14) | 0.0366 (14) | 0.0139 (11) | 0.0142 (11) | 0.0137 (11) |
C28 | 0.0283 (12) | 0.0329 (13) | 0.0304 (12) | 0.0089 (10) | 0.0074 (9) | −0.0010 (10) |
C29 | 0.0306 (11) | 0.0195 (11) | 0.0322 (12) | 0.0034 (9) | 0.0143 (9) | 0.0045 (9) |
C30 | 0.0342 (13) | 0.0211 (11) | 0.0415 (14) | 0.0000 (10) | 0.0135 (11) | −0.0001 (10) |
C31 | 0.0408 (14) | 0.0254 (12) | 0.0356 (14) | 0.0047 (10) | 0.0100 (11) | 0.0089 (10) |
Br1 | 0.02077 (11) | 0.03140 (13) | 0.02841 (12) | 0.00005 (9) | 0.00584 (8) | 0.00150 (9) |
Br2 | 0.03523 (13) | 0.02893 (13) | 0.02839 (13) | −0.00436 (9) | 0.01185 (9) | −0.00585 (9) |
N1—C10 | 1.333 (3) | C14—C15 | 1.412 (3) |
N1—C8 | 1.376 (3) | C14—C18 | 1.504 (3) |
N1—C7 | 1.468 (3) | C15—C16 | 1.387 (4) |
N2—C10 | 1.337 (3) | C15—C31 | 1.507 (3) |
N2—C9 | 1.371 (3) | C16—C17 | 1.385 (3) |
N2—C11 | 1.474 (3) | C16—H16A | 0.9300 |
N3—C19 | 1.334 (3) | C17—C30 | 1.506 (3) |
N3—C20 | 1.371 (3) | C18—H18A | 0.9700 |
N3—C18 | 1.472 (3) | C18—H18B | 0.9700 |
N4—C19 | 1.330 (3) | C19—H19A | 0.9300 |
N4—C21 | 1.382 (3) | C20—C21 | 1.352 (3) |
N4—C22 | 1.479 (3) | C20—H20A | 0.9300 |
C1—C2 | 1.387 (4) | C21—H21A | 0.9300 |
C1—C6 | 1.391 (3) | C22—C23 | 1.514 (3) |
C1—H1A | 0.9300 | C22—H22A | 0.9700 |
C2—C3 | 1.386 (5) | C22—H22B | 0.9700 |
C2—H2A | 0.9300 | C23—C28 | 1.384 (3) |
C3—C4 | 1.380 (4) | C23—C24 | 1.388 (3) |
C3—H3A | 0.9300 | C24—C25 | 1.385 (3) |
C4—C5 | 1.390 (4) | C24—H24A | 0.9300 |
C4—H4A | 0.9300 | C25—C26 | 1.379 (4) |
C5—C6 | 1.385 (3) | C25—H25A | 0.9300 |
C5—H5A | 0.9300 | C26—C27 | 1.380 (4) |
C6—C7 | 1.505 (3) | C26—H26A | 0.9300 |
C7—H7A | 0.9700 | C27—C28 | 1.384 (4) |
C7—H7B | 0.9700 | C27—H27A | 0.9300 |
C8—C9 | 1.355 (3) | C28—H28A | 0.9300 |
C8—H8A | 0.9300 | C29—H29A | 0.9600 |
C9—H9A | 0.9300 | C29—H29B | 0.9600 |
C10—H10A | 0.9300 | C29—H29C | 0.9600 |
C11—C12 | 1.510 (3) | C30—H30A | 0.9600 |
C11—H11A | 0.9700 | C30—H30B | 0.9600 |
C11—H11B | 0.9700 | C30—H30C | 0.9600 |
C12—C13 | 1.402 (3) | C31—H31A | 0.9600 |
C12—C17 | 1.408 (3) | C31—H31B | 0.9600 |
C13—C14 | 1.402 (3) | C31—H31C | 0.9600 |
C13—C29 | 1.515 (3) | ||
C10—N1—C8 | 109.14 (18) | C17—C16—C15 | 122.8 (2) |
C10—N1—C7 | 124.97 (19) | C17—C16—H16A | 118.6 |
C8—N1—C7 | 125.85 (19) | C15—C16—H16A | 118.6 |
C10—N2—C9 | 108.90 (18) | C16—C17—C12 | 118.1 (2) |
C10—N2—C11 | 125.60 (19) | C16—C17—C30 | 120.1 (2) |
C9—N2—C11 | 125.44 (19) | C12—C17—C30 | 121.8 (2) |
C19—N3—C20 | 109.00 (19) | N3—C18—C14 | 113.49 (18) |
C19—N3—C18 | 126.1 (2) | N3—C18—H18A | 108.9 |
C20—N3—C18 | 124.88 (19) | C14—C18—H18A | 108.9 |
C19—N4—C21 | 109.05 (19) | N3—C18—H18B | 108.9 |
C19—N4—C22 | 124.8 (2) | C14—C18—H18B | 108.9 |
C21—N4—C22 | 125.9 (2) | H18A—C18—H18B | 107.7 |
C2—C1—C6 | 120.8 (3) | N4—C19—N3 | 108.0 (2) |
C2—C1—H1A | 119.6 | N4—C19—H19A | 126.0 |
C6—C1—H1A | 119.6 | N3—C19—H19A | 126.0 |
C3—C2—C1 | 120.4 (3) | C21—C20—N3 | 107.3 (2) |
C3—C2—H2A | 119.8 | C21—C20—H20A | 126.3 |
C1—C2—H2A | 119.8 | N3—C20—H20A | 126.3 |
C4—C3—C2 | 119.0 (3) | C20—C21—N4 | 106.6 (2) |
C4—C3—H3A | 120.5 | C20—C21—H21A | 126.7 |
C2—C3—H3A | 120.5 | N4—C21—H21A | 126.7 |
C3—C4—C5 | 120.9 (3) | N4—C22—C23 | 110.43 (17) |
C3—C4—H4A | 119.6 | N4—C22—H22A | 109.6 |
C5—C4—H4A | 119.6 | C23—C22—H22A | 109.6 |
C6—C5—C4 | 120.4 (2) | N4—C22—H22B | 109.6 |
C6—C5—H5A | 119.8 | C23—C22—H22B | 109.6 |
C4—C5—H5A | 119.8 | H22A—C22—H22B | 108.1 |
C5—C6—C1 | 118.7 (2) | C28—C23—C24 | 119.5 (2) |
C5—C6—C7 | 123.8 (2) | C28—C23—C22 | 121.0 (2) |
C1—C6—C7 | 117.5 (2) | C24—C23—C22 | 119.5 (2) |
N1—C7—C6 | 113.04 (19) | C25—C24—C23 | 119.9 (2) |
N1—C7—H7A | 109.0 | C25—C24—H24A | 120.0 |
C6—C7—H7A | 109.0 | C23—C24—H24A | 120.0 |
N1—C7—H7B | 109.0 | C26—C25—C24 | 120.2 (3) |
C6—C7—H7B | 109.0 | C26—C25—H25A | 119.9 |
H7A—C7—H7B | 107.8 | C24—C25—H25A | 119.9 |
C9—C8—N1 | 106.7 (2) | C25—C26—C27 | 120.1 (2) |
C9—C8—H8A | 126.6 | C25—C26—H26A | 119.9 |
N1—C8—H8A | 126.6 | C27—C26—H26A | 119.9 |
C8—C9—N2 | 107.3 (2) | C26—C27—C28 | 119.8 (2) |
C8—C9—H9A | 126.3 | C26—C27—H27A | 120.1 |
N2—C9—H9A | 126.3 | C28—C27—H27A | 120.1 |
N1—C10—N2 | 107.92 (19) | C23—C28—C27 | 120.4 (2) |
N1—C10—H10A | 126.0 | C23—C28—H28A | 119.8 |
N2—C10—H10A | 126.0 | C27—C28—H28A | 119.8 |
N2—C11—C12 | 112.17 (17) | C13—C29—H29A | 109.5 |
N2—C11—H11A | 109.2 | C13—C29—H29B | 109.5 |
C12—C11—H11A | 109.2 | H29A—C29—H29B | 109.5 |
N2—C11—H11B | 109.2 | C13—C29—H29C | 109.5 |
C12—C11—H11B | 109.2 | H29A—C29—H29C | 109.5 |
H11A—C11—H11B | 107.9 | H29B—C29—H29C | 109.5 |
C13—C12—C17 | 120.6 (2) | C17—C30—H30A | 109.5 |
C13—C12—C11 | 120.90 (19) | C17—C30—H30B | 109.5 |
C17—C12—C11 | 118.5 (2) | H30A—C30—H30B | 109.5 |
C12—C13—C14 | 119.6 (2) | C17—C30—H30C | 109.5 |
C12—C13—C29 | 120.7 (2) | H30A—C30—H30C | 109.5 |
C14—C13—C29 | 119.7 (2) | H30B—C30—H30C | 109.5 |
C13—C14—C15 | 119.9 (2) | C15—C31—H31A | 109.5 |
C13—C14—C18 | 120.7 (2) | C15—C31—H31B | 109.5 |
C15—C14—C18 | 119.2 (2) | H31A—C31—H31B | 109.5 |
C16—C15—C14 | 118.6 (2) | C15—C31—H31C | 109.5 |
C16—C15—C31 | 119.7 (2) | H31A—C31—H31C | 109.5 |
C14—C15—C31 | 121.7 (2) | H31B—C31—H31C | 109.5 |
C6—C1—C2—C3 | −0.7 (5) | C13—C14—C15—C31 | 179.4 (2) |
C1—C2—C3—C4 | 0.7 (5) | C18—C14—C15—C31 | −5.0 (3) |
C2—C3—C4—C5 | 0.2 (4) | C14—C15—C16—C17 | −3.1 (3) |
C3—C4—C5—C6 | −1.0 (4) | C31—C15—C16—C17 | 176.5 (2) |
C4—C5—C6—C1 | 0.9 (4) | C15—C16—C17—C12 | 2.4 (3) |
C4—C5—C6—C7 | −178.8 (2) | C15—C16—C17—C30 | −177.1 (2) |
C2—C1—C6—C5 | −0.1 (4) | C13—C12—C17—C16 | 2.5 (3) |
C2—C1—C6—C7 | 179.7 (3) | C11—C12—C17—C16 | −175.25 (18) |
C10—N1—C7—C6 | −96.1 (3) | C13—C12—C17—C30 | −178.02 (19) |
C8—N1—C7—C6 | 81.5 (3) | C11—C12—C17—C30 | 4.2 (3) |
C5—C6—C7—N1 | −6.2 (3) | C19—N3—C18—C14 | 30.3 (3) |
C1—C6—C7—N1 | 174.1 (2) | C20—N3—C18—C14 | −152.4 (2) |
C10—N1—C8—C9 | 0.2 (3) | C13—C14—C18—N3 | −116.1 (2) |
C7—N1—C8—C9 | −177.8 (2) | C15—C14—C18—N3 | 68.3 (3) |
N1—C8—C9—N2 | −1.0 (3) | C21—N4—C19—N3 | −0.3 (3) |
C10—N2—C9—C8 | 1.6 (3) | C22—N4—C19—N3 | 174.75 (19) |
C11—N2—C9—C8 | 179.0 (2) | C20—N3—C19—N4 | 0.5 (3) |
C8—N1—C10—N2 | 0.8 (2) | C18—N3—C19—N4 | 178.19 (19) |
C7—N1—C10—N2 | 178.76 (19) | C19—N3—C20—C21 | −0.6 (3) |
C9—N2—C10—N1 | −1.5 (2) | C18—N3—C20—C21 | −178.2 (2) |
C11—N2—C10—N1 | −178.90 (19) | N3—C20—C21—N4 | 0.4 (3) |
C10—N2—C11—C12 | −42.9 (3) | C19—N4—C21—C20 | 0.0 (3) |
C9—N2—C11—C12 | 140.1 (2) | C22—N4—C21—C20 | −175.0 (2) |
N2—C11—C12—C13 | 101.9 (2) | C19—N4—C22—C23 | −79.9 (3) |
N2—C11—C12—C17 | −80.3 (2) | C21—N4—C22—C23 | 94.4 (3) |
C17—C12—C13—C14 | −6.5 (3) | N4—C22—C23—C28 | −88.0 (3) |
C11—C12—C13—C14 | 171.21 (18) | N4—C22—C23—C24 | 89.8 (3) |
C17—C12—C13—C29 | 173.11 (18) | C28—C23—C24—C25 | 1.2 (3) |
C11—C12—C13—C29 | −9.2 (3) | C22—C23—C24—C25 | −176.7 (2) |
C12—C13—C14—C15 | 5.7 (3) | C23—C24—C25—C26 | 1.2 (4) |
C29—C13—C14—C15 | −173.94 (18) | C24—C25—C26—C27 | −2.7 (4) |
C12—C13—C14—C18 | −169.92 (18) | C25—C26—C27—C28 | 1.8 (4) |
C29—C13—C14—C18 | 10.4 (3) | C24—C23—C28—C27 | −2.1 (3) |
C13—C14—C15—C16 | −1.0 (3) | C22—C23—C28—C27 | 175.7 (2) |
C18—C14—C15—C16 | 174.71 (19) | C26—C27—C28—C23 | 0.6 (4) |
D—H···A | D—H | H···A | D···A | D—H···A |
C7—H7A···Br2 | 0.97 | 2.90 | 3.754 (2) | 147 |
C7—H7B···Br1i | 0.97 | 2.92 | 3.787 (2) | 149 |
C8—H8A···Br2 | 0.93 | 2.81 | 3.496 (3) | 132 |
C10—H10A···Br1i | 0.93 | 2.74 | 3.565 (2) | 148 |
C18—H18B···Br2ii | 0.97 | 2.74 | 3.702 (2) | 172 |
C19—H19A···Br1i | 0.93 | 2.74 | 3.553 (2) | 147 |
C21—H21A···Br2iii | 0.93 | 2.83 | 3.603 (3) | 141 |
Symmetry codes: (i) x+1, y, z; (ii) x, −y+3/2, z+1/2; (iii) x+1, −y+3/2, z+1/2. |
Experimental details
Crystal data | |
Chemical formula | C31H34N42+·2Br− |
Mr | 622.44 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 100 |
a, b, c (Å) | 8.9851 (2), 12.8044 (2), 25.6419 (5) |
β (°) | 102.611 (1) |
V (Å3) | 2878.90 (10) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 2.84 |
Crystal size (mm) | 0.49 × 0.43 × 0.21 |
Data collection | |
Diffractometer | Bruker SMART APEXII CCD area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Bruker, 2009) |
Tmin, Tmax | 0.337, 0.585 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 32884, 8490, 6550 |
Rint | 0.036 |
(sin θ/λ)max (Å−1) | 0.708 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.040, 0.101, 1.04 |
No. of reflections | 8490 |
No. of parameters | 337 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 1.28, −0.40 |
Computer programs: APEX2 (Bruker, 2009), SAINT (Bruker, 2009), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).
D—H···A | D—H | H···A | D···A | D—H···A |
C7—H7A···Br2 | 0.97 | 2.90 | 3.754 (2) | 147 |
C7—H7B···Br1i | 0.97 | 2.92 | 3.787 (2) | 149 |
C8—H8A···Br2 | 0.93 | 2.81 | 3.496 (3) | 132 |
C10—H10A···Br1i | 0.93 | 2.74 | 3.565 (2) | 148 |
C18—H18B···Br2ii | 0.97 | 2.74 | 3.702 (2) | 172 |
C19—H19A···Br1i | 0.93 | 2.74 | 3.553 (2) | 147 |
C21—H21A···Br2iii | 0.93 | 2.83 | 3.603 (3) | 141 |
Symmetry codes: (i) x+1, y, z; (ii) x, −y+3/2, z+1/2; (iii) x+1, −y+3/2, z+1/2. |
Footnotes
‡Thomson Reuters ResearcherID: A-3561-2009.
Acknowledgements
RAH thanks Universiti Sains Malaysia (USM) for the FRGS fund (203/PKIMIA/671115), short term grant (304/PKIMIA/639001) and RU grants (1001/PKIMIA/813023 and 1001/PKIMIA/811157). AWS thanks USM for the RU grant (1001/PKIMIA/843090). HKF and MH thank the Malaysian Government and USM for the Research University grant No. 1001/PFIZIK/811160. MH also thanks Universiti Sains Malaysia for a post-doctoral research fellowship.
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This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
N-Heterocyclic carbenes (NHCs) have found widespread applications as ligands in organometallic chemistry during recent years (Winkelmann & Navarro, 2010). They typically have strong σ-donor properties but poor π-acceptor character and have been widely employed as alternatives to phosphine ligands to stabilise transition metal complexes. NHCs are relatively inexpensive, non-toxic and easily prepared from azolium salts (Papini et al., 2008). Notably, NHCs also exhibit excellent catalytic activity in metal-free organocatalysis (Marion et al., 2007) including umpolung and condensation of carbonyl compounds (Burstein & Glorius, 2004; Sohn et al., 2004) and transesterification reactions (Grasa et al., 2002; Singh & Nolan, 2005).
The asymmetric unit of the title compound, (Fig. 1), consists of one 1,3-bis(3-benzylimidazolium-1-ylmethyl)mesitylene cation and two bromide anions. The central benzene ring (C12–C17) makes dihedral angles of 80.47 (12)° and 82.78 (12)° with the adjacent imidazole rings (N1/N2/C8–C10) and (N3/N4/C19–C21). The dihedral angle between the two terminal phenyl rings (C1–C6) and (C23–C28) is 79.16 (13)°.
In the crystal structure (Fig. 2), the cations and anions are linked together via intermolecular C—H···Br (Table 1) hydrogen bonds, forming one-dimensional supramolecular chains along the c-axis.