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Acta Cryst. (2009). E65, o522    [ doi:10.1107/S1600536809004759 ]

1,4-Bis(benzimidazol-2-yl)benzene dimethylformamide disolvate

D.-H. Wu and L. Hu

Abstract top

The aromatic molecule of the title compound, C20H14N4·2C3H7NO, occupies a special position on an inversion center. The benzimidazole unit (planar to within 0.008 Å) forms a dihedral angle of 9.1 (2)° with the central benzene ring. The benzimidazole H atom participates in a hydrogen bond with the dimethylformamide solvent molecule, thus giving rise to the title 1:2 aggregate. These aggregates are further linked in the crystal structure by aromatic [pi]-[pi] stacking interactions [centroid-centroid distance = 6.356 (2) Å].

Comment top

Benzimidazole systems continue to attract considerable attention in chemical synthesis, structural science and applied medicinal research (Zarrinmayeh et al., 1998; Gallagher et al., 2001; Howarth & Hanlon, 2001). Here we report the crystal structure of the title compound, 1,4-bis(2-benzimidazolyl)benzene bis(dimethylformamide) solvate.

The 1,4-bis(2-benzimidazolyl)benzene molecule occupies a special position on the inversion center, and benzimidazole moiety (planar within 0.0078 Å) forms dihedral angle of 9.1 (2)° with the plane of the central benzene ring (Fig. 1). This shows that 1,4-(2-benzimidazolyl)benzene molecule in the structure of the title compound deviates from planarity to a much lesser degree than in the unsolvated structure, wherein the corresponding dihedral angle is equal to 31.0° (Bei et al., 2000; Dudd et al., 2003).

The only `active' hydrogen atom H2 participates in the H-bond with the carbonyl atom of the dimethylformamide molecule (H2···O1 1.95 Å, N2—H2···O1 165.1°) thus giving rise to the 1,4-bis(2-benzimidazolyl)benzene:DMFA (1:2) complexes, which are further linked in crystal through the π—π stacking interactions.

Related literature top

For background literature concerning benzimidazole compounds, see: Zarrinmayeh et al. (1998); Gallagher et al. (2001); Howarth & Hanlon (2001). For the unsolvated structure, see: Bei et al. (2000); Dudd et al. (2003).

Experimental top

The title compound was synthesized by refluxing terephthalaldehyde (0.53 g, 4 mmol) and benzene-1,2-diamine (0.86 g, 8 mmol) in absolute methanol (50 ml) for 8 h. After cooling to room temperature, the yellow solid thus formed was isolated and dried under vacuum (1.13 g, yield 80 %). Single crystals suitable for X-ray structure analysis were obtained by the slow evaporation of a dimethylformamide solution in air.

Refinement top

H atoms were placed in calculated positions (N—H = 0.86 Å; C—H = 0.93 Å and 0.96 Å for Csp2 and Csp3 atoms, respectively), assigned fixed Uiso values [Uiso = 1.2Ueq(Csp2/N) and 1.5Ueq(Csp3)] and allowed to ride.

Computing details top

Data collection: CrystalClear (Rigaku, 2005); cell refinement: CrystalClear (Rigaku, 2005); data reduction: CrystalClear (Rigaku, 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 structure of 1,4-bis(2-benzimidazolyl)benzene and dimethylformamide molecules in the crystal of the title compound, showing the atomic numbering scheme and 30% probability displacement ellipsoids. Unlabelled atoms are related to the labelled atoms by the (1 - x, -y, 1 - z) symmetry transformation.
1,4-Bis(benzimidazol-2-yl)benzene dimethylformamide disolvate top
Crystal data top
C20H14N4·2C3H7NOF(000) = 484
Mr = 456.54Dx = 1.278 Mg m−3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 9216 reflections
a = 6.3556 (13) Åθ = 3.0–27.7°
b = 20.931 (2) ŵ = 0.08 mm−1
c = 9.0097 (18) ÅT = 291 K
β = 98.26 (2)°Block, yellow
V = 1186.1 (4) Å30.32 × 0.26 × 0.24 mm
Z = 2
Data collection top
Rigaku Mercury2
diffractometer		2723 independent reflections
Radiation source: fine-focus sealed tube1718 reflections with I > 2σ(I)
graphiteRint = 0.054
Detector resolution: 13.6612 pixels mm-1θmax = 27.5°, θmin = 3.0°
CCD profile fitting scansh = −8→8
Absorption correction: multi-scan
(CrystalClear; Rigaku, 2005)		k = −27→27
Tmin = 0.970, Tmax = 0.990l = −11→11
12310 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.057Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.158H-atom parameters constrained
S = 1.00 w = 1/[σ2(Fo2) + (0.0615P)2 + 0.4757P]
where P = (Fo2 + 2Fc2)/3
2723 reflections(Δ/σ)max < 0.001
154 parametersΔρmax = 0.24 e Å−3
0 restraintsΔρmin = −0.21 e Å−3
Crystal data top
C20H14N4·2C3H7NOV = 1186.1 (4) Å3
Mr = 456.54Z = 2
Monoclinic, P21/nMo Kα radiation
a = 6.3556 (13) ŵ = 0.08 mm−1
b = 20.931 (2) ÅT = 291 K
c = 9.0097 (18) Å0.32 × 0.26 × 0.24 mm
β = 98.26 (2)°
Data collection top
Rigaku Mercury2
diffractometer		2723 independent reflections
Absorption correction: multi-scan
(CrystalClear; Rigaku, 2005)		1718 reflections with I > 2σ(I)
Tmin = 0.970, Tmax = 0.990Rint = 0.054
12310 measured reflectionsθmax = 27.5°
Refinement top
R[F2 > 2σ(F2)] = 0.057H-atom parameters constrained
wR(F2) = 0.158Δρmax = 0.24 e Å−3
S = 1.00Δρmin = −0.21 e Å−3
2723 reflectionsAbsolute structure: ?
154 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
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 > 2sigma(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
C10.4424 (3)0.03145 (10)0.6222 (2)0.0442 (5)
H1A0.40270.05270.70450.053*
C20.6334 (3)0.04722 (9)0.5722 (2)0.0394 (5)
C30.6877 (3)0.01491 (10)0.4482 (2)0.0454 (5)
H3A0.81400.02490.41260.054*
C40.7705 (3)0.09548 (9)0.6530 (2)0.0396 (5)
C50.9076 (3)0.16201 (10)0.8206 (2)0.0431 (5)
C61.0397 (3)0.16157 (9)0.7099 (2)0.0425 (5)
C71.2235 (4)0.19770 (11)0.7212 (3)0.0563 (6)
H7A1.31190.19660.64740.068*
C81.2694 (4)0.23526 (12)0.8464 (3)0.0655 (7)
H8A1.39140.26040.85750.079*
C91.1379 (4)0.23673 (12)0.9574 (3)0.0638 (7)
H9A1.17340.26301.04040.077*
C100.9577 (4)0.20035 (11)0.9471 (3)0.0578 (6)
H10A0.87130.20121.02210.069*
C110.7511 (4)0.87860 (14)0.7174 (3)0.0663 (7)
H11A0.66680.84860.66070.080*
C120.7988 (5)0.95068 (16)0.9240 (3)0.0905 (10)
H12A0.93050.95840.88650.136*
H12B0.82770.93571.02550.136*
H12C0.71870.98970.92100.136*
C130.4746 (5)0.88579 (18)0.8728 (4)0.0984 (11)
H13A0.40930.85400.80420.148*
H13B0.38500.92290.86810.148*
H13C0.49370.86890.97280.148*
N10.7398 (3)0.12012 (9)0.78322 (19)0.0470 (5)
N20.9489 (3)0.11884 (8)0.60413 (19)0.0442 (4)
H2A0.99570.10870.52230.053*
N30.6781 (3)0.90317 (9)0.8324 (2)0.0526 (5)
O10.9230 (3)0.89199 (11)0.6780 (2)0.0845 (6)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0431 (11)0.0534 (13)0.0382 (11)0.0016 (10)0.0135 (9)−0.0061 (9)
C20.0390 (11)0.0442 (11)0.0355 (10)0.0044 (9)0.0071 (8)0.0028 (8)
C30.0397 (11)0.0537 (12)0.0451 (12)−0.0003 (10)0.0144 (9)−0.0011 (10)
C40.0386 (11)0.0425 (11)0.0385 (10)0.0033 (9)0.0088 (9)0.0043 (9)
C50.0431 (11)0.0414 (11)0.0457 (12)0.0015 (9)0.0088 (9)0.0011 (9)
C60.0441 (11)0.0398 (11)0.0440 (11)0.0015 (9)0.0080 (9)0.0061 (9)
C70.0494 (13)0.0570 (14)0.0655 (15)−0.0081 (11)0.0183 (11)0.0020 (12)
C80.0543 (15)0.0584 (15)0.0827 (19)−0.0146 (12)0.0066 (13)−0.0018 (13)
C90.0672 (16)0.0582 (15)0.0649 (16)−0.0106 (13)0.0052 (13)−0.0125 (12)
C100.0635 (15)0.0580 (14)0.0537 (14)−0.0070 (12)0.0146 (12)−0.0107 (11)
C110.0706 (17)0.0797 (18)0.0501 (14)0.0029 (14)0.0129 (13)−0.0001 (13)
C120.112 (3)0.085 (2)0.0701 (19)0.0047 (19)−0.0020 (18)−0.0122 (16)
C130.078 (2)0.126 (3)0.101 (2)−0.001 (2)0.0443 (19)0.023 (2)
N10.0467 (10)0.0530 (10)0.0439 (10)−0.0042 (8)0.0158 (8)−0.0052 (8)
N20.0454 (10)0.0488 (10)0.0414 (9)−0.0018 (8)0.0166 (8)−0.0012 (8)
N30.0540 (11)0.0625 (12)0.0438 (10)0.0004 (9)0.0153 (9)0.0007 (9)
O10.0695 (12)0.1293 (18)0.0613 (12)0.0077 (12)0.0318 (10)0.0092 (11)
Geometric parameters (Å, °) top
C1—C3i1.370 (3)C8—H8A0.9300
C1—C21.394 (3)C9—C101.367 (3)
C1—H1A0.9300C9—H9A0.9300
C2—C31.391 (3)C10—H10A0.9300
C2—C41.459 (3)C11—O11.229 (3)
C3—C1i1.370 (3)C11—N31.300 (3)
C3—H3A0.9300C11—H11A0.9300
C4—N11.322 (2)C12—N31.441 (3)
C4—N21.364 (2)C12—H12A0.9600
C5—N11.384 (3)C12—H12B0.9600
C5—C101.393 (3)C12—H12C0.9600
C5—C61.393 (3)C13—N31.440 (3)
C6—N21.372 (3)C13—H13A0.9600
C6—C71.383 (3)C13—H13B0.9600
C7—C81.372 (4)C13—H13C0.9600
C7—H7A0.9300N2—H2A0.8600
C8—C91.393 (4)
C3i—C1—C2120.91 (18)C8—C9—H9A119.3
C3i—C1—H1A119.5C9—C10—C5117.9 (2)
C2—C1—H1A119.5C9—C10—H10A121.1
C3—C2—C1118.20 (19)C5—C10—H10A121.1
C3—C2—C4122.55 (18)O1—C11—N3125.0 (3)
C1—C2—C4119.23 (17)O1—C11—H11A117.5
C1i—C3—C2120.89 (19)N3—C11—H11A117.5
C1i—C3—H3A119.6N3—C12—H12A109.5
C2—C3—H3A119.6N3—C12—H12B109.5
N1—C4—N2112.48 (18)H12A—C12—H12B109.5
N1—C4—C2124.01 (18)N3—C12—H12C109.5
N2—C4—C2123.48 (17)H12A—C12—H12C109.5
N1—C5—C10129.9 (2)H12B—C12—H12C109.5
N1—C5—C6110.11 (18)N3—C13—H13A109.5
C10—C5—C6120.0 (2)N3—C13—H13B109.5
N2—C6—C7132.4 (2)H13A—C13—H13B109.5
N2—C6—C5105.38 (17)N3—C13—H13C109.5
C7—C6—C5122.2 (2)H13A—C13—H13C109.5
C8—C7—C6116.9 (2)H13B—C13—H13C109.5
C8—C7—H7A121.6C4—N1—C5104.84 (16)
C6—C7—H7A121.6C4—N2—C6107.19 (16)
C7—C8—C9121.6 (2)C4—N2—H2A126.4
C7—C8—H8A119.2C6—N2—H2A126.4
C9—C8—H8A119.2C11—N3—C13122.5 (3)
C10—C9—C8121.5 (2)C11—N3—C12120.5 (2)
C10—C9—H9A119.3C13—N3—C12117.0 (2)
Symmetry codes: (i) −x+1, −y, −z+1.
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
N2—H2A···O1ii0.861.952.787 (3)165
Symmetry codes: (ii) −x+2, −y+1, −z+1.
Table 1
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
N2—H2A···O1i0.861.952.787 (3)165
Symmetry codes: (i) −x+2, −y+1, −z+1.
Acknowledgements top

The authors appreciate the help of Professor Dr Rengen Xiong and the financial support of Jiangsu Planned Projects for Postdoctoral Research Funds (grant No. 0802003B).

references
References top

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