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Acta Cryst. (2008). E64, m1198    [ doi:10.1107/S1600536808026937 ]

Bis[3-allyl-1-(4-cyanobenzyl)-2-methylbenzimidazolium] di-[mu]-bromido-bis[bromidocuprate(I)]

G.-H. Xu and W. Wang

Abstract top

The asymmetric unit of the title compound, (C19H18N3)2[Cu2Br4], contains one cation and one half-anion; there is a centre of symmetry mid-way between the two Cu atoms. In the cation, the nearly planar benzimidazole ring system is oriented at dihedral angles of 75.31 (3) and 21.39 (3)° with respect to the cyanobenzyl and allyl groups, respectively. The dihedral angle between cyanobenzyl and allyl groups is 87.94 (3)°. In the crystal structure, intermolecular C-H...Br hydrogen bonds link the molecules. There is a C-H...[pi] contact between the cyanobenzyl ring and the anion; [pi]-[pi] contacts also exist between the benzimidazole ring systems as well as between the anion and the cyanobenzyl ring [centroid-centroid distances = 4.024 (1) and 4.617 (1) Å, respectively].

Comment top

The asymmetric unit of the title compound contains one cation and one-half anion (Fig. 1). In the cation, rings A (N2/N3/C9/C14/C19), B (C14—C19) and C (C2—C7) are, of course, planar and the dihedral angles between them are A/B = 1.47 (3)°, A/C = 75.18 (4)° and B/C = 75.46 (4)°. So, the benzimidazole ring system is nearly planar, and it is oriented with respect to the cyanobenzyl and allyl groups at dihedral angles of 75.31 (3)° and 21.39 (3)°, respectively. The dihedral angle between cyanobenzyl and allyl groups is 87.94 (3)°.

In the crystal structure, intermolecular C—H···Br hydrogen bonds link the molecules (Fig. 2), in which they may be effective in the stabilization of the structure. There also exists a C—H···π contact (Table 1) between the cyanobenzyl ring and the anion. The π—π contacts between the rings A and B as well as the anion and the ring C, Cg2···Cg4i and Cg3···Cg1ii [symmetry codes: (i) -x, 1 - y, 1 - z; (ii) x, y, z - 1, where Cg1, Cg2, Cg3 and Cg4 are centroids of the anion, the rings A, C and B, respectively] further stabilize the structure, with centroid-centroid distances of 4.024 (1) and 4.617 (1) Å, respectively.

Related literature top

For related literature, see: Aaker et al. (2005). Cg1 is the centroid of the anion.

Experimental top

The synthesis of (1) (Scheme 1) was reported, previously (Aaker et al., 2005). The mixture of (1) (2.47 g, 10 mmol), allyl bromide (1.21 g, 10 mmol) and Na2CO3 (0.53 g, 5 mmol) was stirred in THF (50 ml) under reflux for 24 h to obtain (2) (Scheme 1) with high yield (90%). The colorless crystals suitable for X-ray analysis were obtained from the mixture of (2) (73.6 mg, 0.2 mmol), CuBr (28.8 mg, 0.2 mmol) and methanol (2 ml) sealed in a glass tube maintaining at 353 K for 5 d.

Refinement top

H atoms were positioned geometrically, with C—H = 0.93, 0.97 and 0.96 Å for aromatic and methylene (for allyl C13 atom), methylene and methyl H, respectively, and constrained to ride on their parent atoms with Uiso(H) = xUeq(C), where x = 1.5 for methyl H and x = 1.2 for all other H atoms.

Computing details top

Data collection: CrystalClear (Rigaku/MSC, 2005); cell refinement: CrystalClear (Rigaku/MSC, 2005); data reduction: CrystalStructure (Rigaku/MSC, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title molecule, with the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level [symmetry code: (A) -x, 1 - y, 2 - z].
[Figure 2] Fig. 2. A partial packing diagram of the title compound, viewed along the a axis. Hydrogen bonds are shown as dashed lines.
[Figure 3] Fig. 3. The formation of the title compound.
Bis[3-allyl-1-(4-cyanobenzyl)-2-methylbenzimidazolium] di-µ-bromido-bis[bromidocuprate(I)] top
Crystal data top
(C19H18N3)2[Cu2Br4]Z = 1
Mr = 1023.44F000 = 504
Triclinic, P1Dx = 1.701 Mg m−3
Hall symbol: -P 1Mo Kα radiation
λ = 0.71073 Å
a = 9.6407 (5) ÅCell parameters from 2257 reflections
b = 10.1029 (11) Åθ = 2.8–27.5º
c = 11.0389 (6) ŵ = 5.10 mm−1
α = 87.27 (2)ºT = 294 (2) K
β = 69.990 (17)ºPrism, colorless
γ = 81.41 (2)º0.20 × 0.20 × 0.20 mm
V = 998.93 (18) Å3
Data collection top
Rigaku, SCXmini
diffractometer		4517 independent reflections
Radiation source: fine-focus sealed tube2765 reflections with I > 2σ(I)
Monochromator: graphiteRint = 0.052
Detector resolution: 13.6612 pixels mm-1θmax = 27.5º
T = 294(2) Kθmin = 2.8º
ω scansh = −12→12
Absorption correction: multi-scan
(CrystalClear; Rigaku/MSC, 2005)		k = −13→13
Tmin = 0.361, Tmax = 0.375l = −14→14
10227 measured reflections
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.052H-atom parameters constrained
wR(F2) = 0.134  w = 1/[σ2(Fo2) + (0.0636P)2]
where P = (Fo2 + 2Fc2)/3
S = 0.97(Δ/σ)max < 0.001
4517 reflectionsΔρmax = 1.07 e Å−3
226 parametersΔρmin = −0.76 e Å−3
Primary atom site location: structure-invariant direct methodsExtinction correction: none
Crystal data top
(C19H18N3)2[Cu2Br4]γ = 81.41 (2)º
Mr = 1023.44V = 998.93 (18) Å3
Triclinic, P1Z = 1
a = 9.6407 (5) ÅMo Kα
b = 10.1029 (11) ŵ = 5.10 mm−1
c = 11.0389 (6) ÅT = 294 (2) K
α = 87.27 (2)º0.20 × 0.20 × 0.20 mm
β = 69.990 (17)º
Data collection top
Rigaku, SCXmini
diffractometer		4517 independent reflections
Absorption correction: multi-scan
(CrystalClear; Rigaku/MSC, 2005)		2765 reflections with I > 2σ(I)
Tmin = 0.361, Tmax = 0.375Rint = 0.052
10227 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.052226 parameters
wR(F2) = 0.134H-atom parameters constrained
S = 0.97Δρmax = 1.07 e Å−3
4517 reflectionsΔρmin = −0.76 e Å−3
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.

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
xyzUiso*/Ueq
Br10.37052 (6)0.42643 (5)0.73582 (5)0.05337 (18)
Br2−0.06239 (6)0.34357 (6)0.94360 (6)0.0684 (2)
Cu10.14770 (8)0.47171 (8)0.90578 (7)0.0703 (3)
N10.5950 (7)0.0085 (5)−0.2925 (5)0.0873 (18)
N20.2273 (4)0.3449 (4)0.3653 (4)0.0413 (9)
N30.1992 (4)0.2221 (4)0.5394 (3)0.0406 (9)
C10.5454 (7)0.0689 (6)−0.1995 (6)0.0586 (14)
C20.4844 (6)0.1517 (5)−0.0842 (5)0.0486 (12)
C30.3336 (6)0.1632 (5)−0.0149 (5)0.0554 (14)
H3A0.27290.1148−0.03960.067*
C40.2729 (6)0.2476 (5)0.0920 (5)0.0511 (13)
H4A0.17140.25620.13860.061*
C50.3641 (5)0.3188 (5)0.1291 (4)0.0428 (11)
C60.5157 (5)0.3059 (5)0.0593 (5)0.0522 (13)
H6A0.57710.35290.08470.063*
C70.5758 (6)0.2230 (6)−0.0484 (5)0.0551 (13)
H7A0.67700.2155−0.09600.066*
C80.2982 (6)0.4137 (5)0.2437 (4)0.0468 (12)
H8A0.37670.45800.25290.056*
H8B0.22460.48190.22740.056*
C90.2985 (5)0.2755 (5)0.4384 (4)0.0411 (11)
C100.4630 (5)0.2599 (6)0.4119 (5)0.0538 (13)
H10A0.50950.30720.33450.081*
H10B0.50340.16670.40140.081*
H10C0.48180.29590.48290.081*
C110.2307 (6)0.1405 (5)0.6424 (5)0.0511 (12)
H11A0.17530.18480.72430.061*
H11B0.33600.13470.63010.061*
C120.1921 (7)0.0028 (6)0.6483 (6)0.0634 (15)
H12A0.2200−0.04430.57130.076*
C130.1227 (9)−0.0555 (7)0.7528 (8)0.105 (3)
H13C0.0932−0.01120.83140.126*
H13A0.1019−0.14210.74980.126*
C140.0569 (5)0.2589 (5)0.5305 (4)0.0397 (10)
C15−0.0827 (5)0.2331 (5)0.6120 (5)0.0496 (12)
H15A−0.09470.18180.68610.060*
C16−0.2025 (6)0.2887 (6)0.5754 (5)0.0563 (14)
H16A−0.29800.27380.62610.068*
C17−0.1844 (6)0.3659 (5)0.4657 (5)0.0539 (13)
H17A−0.26860.40110.44560.065*
C18−0.0473 (5)0.3928 (5)0.3850 (5)0.0497 (12)
H18A−0.03650.44490.31140.060*
C190.0746 (5)0.3368 (5)0.4208 (4)0.0404 (11)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Br10.0453 (3)0.0604 (3)0.0527 (3)−0.0150 (2)−0.0116 (2)0.0021 (3)
Br20.0466 (3)0.0807 (4)0.0750 (4)−0.0173 (3)−0.0105 (3)−0.0237 (3)
Cu10.0549 (5)0.0929 (6)0.0560 (4)−0.0042 (4)−0.0119 (3)−0.0038 (4)
N10.114 (5)0.076 (4)0.059 (3)−0.020 (3)−0.007 (3)−0.020 (3)
N20.037 (2)0.048 (2)0.037 (2)−0.0122 (17)−0.0077 (16)−0.0018 (18)
N30.040 (2)0.047 (2)0.035 (2)−0.0093 (17)−0.0115 (17)−0.0010 (18)
C10.071 (4)0.054 (3)0.053 (3)−0.016 (3)−0.021 (3)0.001 (3)
C20.061 (3)0.045 (3)0.039 (3)−0.008 (2)−0.015 (2)−0.002 (2)
C30.068 (4)0.058 (3)0.052 (3)−0.025 (3)−0.029 (3)0.002 (3)
C40.044 (3)0.062 (3)0.046 (3)−0.015 (2)−0.011 (2)−0.004 (3)
C50.049 (3)0.045 (3)0.036 (2)−0.016 (2)−0.013 (2)0.004 (2)
C60.039 (3)0.070 (4)0.049 (3)−0.020 (2)−0.011 (2)−0.009 (3)
C70.046 (3)0.071 (4)0.046 (3)−0.014 (3)−0.010 (2)−0.008 (3)
C80.051 (3)0.049 (3)0.038 (3)−0.014 (2)−0.010 (2)−0.001 (2)
C90.042 (3)0.044 (3)0.039 (3)−0.007 (2)−0.014 (2)−0.005 (2)
C100.037 (3)0.072 (4)0.053 (3)−0.014 (2)−0.013 (2)−0.001 (3)
C110.050 (3)0.054 (3)0.055 (3)−0.013 (2)−0.023 (2)0.009 (3)
C120.075 (4)0.057 (3)0.060 (4)−0.007 (3)−0.027 (3)0.003 (3)
C130.132 (7)0.075 (5)0.116 (7)−0.046 (5)−0.041 (6)0.022 (5)
C140.035 (2)0.044 (3)0.039 (3)−0.005 (2)−0.0107 (19)−0.007 (2)
C150.039 (3)0.056 (3)0.046 (3)−0.005 (2)−0.005 (2)−0.002 (2)
C160.033 (3)0.068 (4)0.060 (3)−0.009 (2)−0.002 (2)−0.010 (3)
C170.043 (3)0.059 (3)0.062 (3)−0.003 (2)−0.022 (3)−0.004 (3)
C180.044 (3)0.057 (3)0.051 (3)−0.006 (2)−0.019 (2)−0.002 (3)
C190.038 (3)0.040 (3)0.042 (3)−0.007 (2)−0.011 (2)−0.006 (2)
Geometric parameters (Å, °) top
Br1—Cu12.3181 (10)C8—H8A0.9700
Br2—Cu1i2.4134 (11)C8—H8B0.9700
Br2—Cu12.4710 (10)C9—C101.496 (6)
Cu1—Br2i2.4134 (11)C10—H10A0.9600
Cu1—Cu1i2.8874 (15)C10—H10B0.9600
N1—C11.136 (7)C10—H10C0.9600
N2—C81.476 (6)C11—C121.486 (7)
N2—C91.340 (6)C11—H11A0.9700
N2—C191.401 (5)C11—H11B0.9700
N3—C91.347 (6)C12—C131.285 (8)
N3—C111.462 (6)C12—H12A0.9300
N3—C141.402 (6)C13—H13C0.9300
C2—C11.452 (7)C13—H13A0.9300
C2—C31.381 (7)C14—C151.394 (6)
C2—C71.381 (7)C15—H15A0.9300
C3—C41.392 (7)C16—C151.384 (7)
C3—H3A0.9300C16—C171.382 (7)
C4—H4A0.9300C16—H16A0.9300
C5—C41.385 (6)C17—H17A0.9300
C5—C61.389 (6)C18—C171.376 (7)
C5—C81.519 (6)C18—H18A0.9300
C6—H6A0.9300C19—C141.387 (6)
C7—C61.389 (7)C19—C181.398 (7)
C7—H7A0.9300
Cu1i—Br2—Cu172.46 (3)N2—C9—C10125.1 (4)
Br1—Cu1—Br2i129.22 (4)N3—C9—C10125.3 (4)
Br1—Cu1—Br2122.83 (4)C9—C10—H10A109.5
Br2i—Cu1—Br2107.54 (3)C9—C10—H10B109.5
Br1—Cu1—Cu1i172.96 (5)H10A—C10—H10B109.5
Br2i—Cu1—Cu1i54.69 (3)C9—C10—H10C109.5
Br2—Cu1—Cu1i52.85 (3)H10A—C10—H10C109.5
C9—N2—C19108.6 (4)H10B—C10—H10C109.5
C9—N2—C8125.8 (4)N3—C11—C12113.8 (4)
C19—N2—C8125.5 (4)N3—C11—H11A108.8
C9—N3—C14108.3 (4)C12—C11—H11A108.8
C9—N3—C11127.0 (4)N3—C11—H11B108.8
C14—N3—C11124.8 (4)C12—C11—H11B108.8
N1—C1—C2177.3 (6)H11A—C11—H11B107.7
C7—C2—C3120.7 (4)C13—C12—C11124.3 (6)
C7—C2—C1119.9 (5)C13—C12—H12A117.8
C3—C2—C1119.4 (5)C11—C12—H12A117.8
C2—C3—C4119.8 (5)C12—C13—H13C120.0
C2—C3—H3A120.1C12—C13—H13A120.0
C4—C3—H3A120.1H13C—C13—H13A120.0
C5—C4—C3119.9 (5)C19—C14—C15122.2 (4)
C5—C4—H4A120.1C19—C14—N3106.8 (4)
C3—C4—H4A120.1C15—C14—N3130.9 (5)
C4—C5—C6119.9 (4)C16—C15—C14115.7 (5)
C4—C5—C8120.3 (4)C16—C15—H15A122.2
C6—C5—C8119.8 (4)C14—C15—H15A122.2
C7—C6—C5120.1 (4)C17—C16—C15121.9 (5)
C7—C6—H6A119.9C17—C16—H16A119.0
C5—C6—H6A119.9C15—C16—H16A119.0
C2—C7—C6119.6 (5)C18—C17—C16122.9 (5)
C2—C7—H7A120.2C18—C17—H17A118.5
C6—C7—H7A120.2C16—C17—H17A118.5
N2—C8—C5112.7 (4)C17—C18—C19115.6 (5)
N2—C8—H8A109.0C17—C18—H18A122.2
C5—C8—H8A109.0C19—C18—H18A122.2
N2—C8—H8B109.0C14—C19—C18121.6 (4)
C5—C8—H8B109.0C14—C19—N2106.7 (4)
H8A—C8—H8B107.8C18—C19—N2131.7 (4)
N2—C9—N3109.6 (4)
Cu1i—Br2—Cu1—Br1−173.22 (6)C7—C2—C3—C40.1 (8)
Cu1i—Br2—Cu1—Br2i0.0C1—C2—C7—C6177.6 (5)
C9—N2—C8—C579.9 (6)C3—C2—C7—C60.7 (8)
C19—N2—C8—C5−97.3 (5)C2—C3—C4—C5−0.5 (8)
C8—N2—C9—N3−177.6 (4)C6—C5—C4—C30.1 (8)
C19—N2—C9—N30.0 (5)C8—C5—C4—C3178.5 (5)
C8—N2—C9—C102.5 (7)C4—C5—C6—C70.7 (8)
C19—N2—C9—C10−179.9 (4)C8—C5—C6—C7−177.7 (5)
C8—N2—C19—C14177.4 (4)C4—C5—C8—N261.6 (6)
C9—N2—C19—C14−0.2 (5)C6—C5—C8—N2−119.9 (5)
C8—N2—C19—C18−3.9 (8)C2—C7—C6—C5−1.1 (8)
C9—N2—C19—C18178.5 (5)N3—C11—C12—C13−135.1 (7)
C11—N3—C9—N2−179.4 (4)N3—C14—C15—C16178.1 (5)
C14—N3—C9—N20.2 (5)C19—C14—C15—C160.8 (7)
C11—N3—C9—C100.5 (7)C15—C16—C17—C180.2 (8)
C14—N3—C9—C10−179.9 (5)C17—C16—C15—C14−0.6 (8)
C9—N3—C11—C12−117.9 (5)N2—C19—C14—N30.3 (5)
C14—N3—C11—C1262.6 (6)N2—C19—C14—C15178.1 (4)
C9—N3—C14—C15−177.9 (5)C18—C19—C14—N3−178.5 (4)
C11—N3—C14—C151.7 (8)C18—C19—C14—C15−0.7 (7)
C9—N3—C14—C19−0.3 (5)C19—C18—C17—C160.0 (8)
C11—N3—C14—C19179.3 (4)N2—C19—C18—C17−178.3 (5)
C1—C2—C3—C4−176.8 (5)C14—C19—C18—C170.2 (7)
Symmetry codes: (i) −x, −y+1, −z+2.
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
C8—H8A···Br1ii0.972.903.863 (5)175
C10—H10C···Br10.962.933.788 (5)150
C17—H17A···Br1iii0.932.923.707 (5)143
C4—H4a···Cg1iv0.933.363.746 (2)107.5 (2)
Symmetry codes: (ii) −x+1, −y+1, −z+1; (iii) −x, −y+1, −z+1; (iv) x, y, z−1.
Table 1
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
C8—H8A···Br1i0.972.903.863 (5)175
C10—H10C···Br10.962.933.788 (5)150
C17—H17A···Br1ii0.932.923.707 (5)143
C4—H4a···Cg1iii0.933.363.746 (2)107.5 (2)
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) −x, −y+1, −z+1; (iii) x, y, z−1.
Acknowledgements top

The authors are grateful to the Starter Fund of Southeast University for financial support to purchase the CCD X-ray diffractometer.

references
References top

Aaker, C. B., Desper, J. & Urbinam, J. F. (2005). Cryst. Growth Des. 5, 1283–1293.

Rigaku/MSC. (2005). CrystalClear and CrystalStructure. Rigaku/MSC, The Woodlands, Texas, USA.

Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.