1,4-Bis­(benzimidazol-2-yl)­butane

The title compound, C₁₈H₁₈N₄, lies on an inversion center. The benzimidazolyl moiety is essentially planar. Intermolecular N—H...N hydrogen bonds give rise to an infinite helical chain structure, with the chains stacked by C—H...π and π...π interactions.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.039
• wR factor = 0.106
• Data-to-parameter ratio = 16.1

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry

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Computing details

Data collection: SMART (Bruker,1998); cell refinement: SMART; data reduction: SAINT (Bruker, 1999); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 1998); software used to prepare material for publication: SHELXTL.

1,4-Bis(2-benzimidazolyl)butane

Crystal data

C18H18N4	Dx = 1.31 Mg m^−3
Mr = 290.36	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, Pbca	Cell parameters from 4154 reflections
a = 8.793 (5) Å	θ = 3.3–27.2°
b = 9.366 (5) Å	µ = 0.08 mm^−1
c = 17.881 (10) Å	T = 293 K
V = 1472.6 (14) Å^3	Block, purple
Z = 4	0.5 × 0.3 × 0.27 mm
F(000) = 616

Data collection

Bruker SMART CCD diffractometer	1344 reflections with I > 2σ(I)
φ and ω scans	Rint = 0.019
Absorption correction: empirical (using intensity measurements) (Blessing, 1995)	θmax = 27.2°, θmin = 3.3°
Tmin = 0.897, Tmax = 0.978	h = −9→11
7990 measured reflections	k = −11→11
1614 independent reflections	l = −16→22

Refinement

Refinement on F^2	0 restraints
Least-squares matrix: full	H-atom parameters constrained
R[F^2 > 2σ(F^2)] = 0.039	w = 1/[σ^2(Fo^2) + (0.045P)^2 + 0.5071P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.106	(Δ/σ)max < 0.001
S = 1.05	Δρmax = 0.15 e Å^−3
1614 reflections	Δρmin = −0.17 e Å^−3
100 parameters

Special details

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. The structure was solved by direct methods and all non-H atoms were refined the full-matrix least-squares method with anisotropic displacement parameters. The H atoms were placed in calculated postions and refined using a riding model.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
N1	0.19151 (12)	0.43457 (11)	0.07042 (6)	0.0369 (3)
H1A	0.241	0.3582	0.0594	0.044*
N2	0.11986 (12)	0.66223 (11)	0.06746 (6)	0.0366 (3)
C1	0.08017 (14)	0.44761 (13)	0.12406 (7)	0.0343 (3)
C2	0.01507 (16)	0.35052 (14)	0.17258 (8)	0.0432 (3)
H2B	0.0466	0.2558	0.174	0.052*
C3	−0.09861 (18)	0.40031 (17)	0.21875 (8)	0.0488 (4)
H3A	−0.1444	0.338	0.2524	0.059*
C4	−0.14626 (18)	0.54169 (16)	0.21612 (8)	0.0494 (4)
H4A	−0.2244	0.5716	0.2475	0.059*
C5	−0.08006 (16)	0.63847 (15)	0.16802 (8)	0.0436 (3)
H5A	−0.112	0.7331	0.1668	0.052*
C6	0.03555 (14)	0.59065 (13)	0.12148 (7)	0.0342 (3)
C7	0.20861 (14)	0.56470 (13)	0.03810 (7)	0.0344 (3)
C8	0.30912 (15)	0.58992 (15)	−0.02747 (8)	0.0407 (3)
H8A	0.3451	0.6877	−0.0257	0.049*
H8B	0.2492	0.5794	−0.0727	0.049*
C9	0.44584 (15)	0.49136 (14)	−0.03266 (7)	0.0391 (3)
H9A	0.5	0.5108	−0.0788	0.047*
H9B	0.4108	0.3932	−0.0345	0.047*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.0358 (6)	0.0284 (5)	0.0465 (6)	0.0034 (4)	0.0033 (5)	0.0025 (4)
N2	0.0355 (6)	0.0303 (5)	0.0439 (6)	0.0016 (4)	0.0019 (5)	0.0027 (4)
C1	0.0316 (6)	0.0329 (6)	0.0384 (7)	−0.0017 (5)	−0.0020 (5)	0.0006 (5)
C2	0.0463 (8)	0.0359 (7)	0.0475 (8)	−0.0037 (6)	−0.0014 (6)	0.0073 (6)
C3	0.0496 (8)	0.0532 (8)	0.0436 (8)	−0.0095 (7)	0.0053 (6)	0.0074 (6)
C4	0.0469 (8)	0.0572 (9)	0.0441 (8)	−0.0003 (7)	0.0101 (6)	−0.0031 (7)
C5	0.0444 (8)	0.0404 (7)	0.0461 (8)	0.0047 (6)	0.0040 (6)	−0.0028 (6)
C6	0.0335 (6)	0.0325 (6)	0.0367 (7)	−0.0011 (5)	−0.0020 (5)	0.0004 (5)
C7	0.0295 (6)	0.0316 (6)	0.0420 (7)	−0.0006 (5)	−0.0021 (5)	0.0039 (5)
C8	0.0369 (7)	0.0413 (7)	0.0438 (7)	0.0011 (6)	0.0028 (5)	0.0068 (6)
C9	0.0351 (7)	0.0396 (7)	0.0425 (7)	0.0000 (5)	0.0051 (5)	−0.0019 (6)

Geometric parameters (Å, º)

N1—C1	1.3759 (17)	C4—C5	1.378 (2)
N1—C7	1.3573 (17)	C4—H4A	0.93
N1—H1A	0.86	C5—C6	1.3880 (19)
N2—C7	1.3112 (17)	C5—H5A	0.93
N2—C6	1.3900 (16)	C7—C8	1.4871 (19)
C1—C6	1.3968 (19)	C8—C9	1.5185 (19)
C1—C2	1.3811 (18)	C8—H8A	0.97
C2—C3	1.378 (2)	C8—H8B	0.97
C2—H2B	0.93	C9—C9^i	1.516 (3)
C3—C4	1.390 (2)	C9—H9A	0.97
C3—H3A	0.93	C9—H9B	0.97
C1—N1—C7	107.22 (10)	C5—C6—C1	119.70 (12)
C1—N1—H1A	126.4	C5—C6—N2	130.66 (12)
C7—N1—H1A	126.4	C1—C6—N2	109.62 (11)
C7—N2—C6	105.04 (11)	N2—C7—N1	112.90 (12)
N1—C1—C6	105.18 (11)	N2—C7—C8	123.96 (12)
N1—C1—C2	132.41 (12)	N1—C7—C8	122.98 (11)
C6—C1—C2	122.41 (13)	C7—C8—C9	114.96 (11)
C3—C2—C1	117.02 (13)	C7—C8—H8A	108.5
C3—C2—H2B	121.5	C9—C8—H8A	108.5
C1—C2—H2B	121.5	C7—C8—H8B	108.5
C2—C3—C4	121.40 (13)	C9—C8—H8B	108.5
C2—C3—H3A	119.3	H8A—C8—H8B	107.5
C4—C3—H3A	119.3	C8—C9—C9^i	112.67 (14)
C5—C4—C3	121.36 (14)	C8—C9—H9A	109.1
C5—C4—H4A	119.3	C9^i—C9—H9A	109.1
C3—C4—H4A	119.3	C8—C9—H9B	109.1
C6—C5—C4	118.11 (13)	C9^i—C9—H9B	109.1
C6—C5—H5A	120.9	H9A—C9—H9B	107.8
C4—C5—H5A	120.9
C7—N1—C1—C6	−0.54 (14)	N1—C1—C6—N2	−0.45 (14)
C7—N1—C1—C2	178.69 (14)	C2—C1—C6—N2	−179.77 (12)
N1—C1—C2—C3	−178.50 (14)	C7—N2—C6—C5	−177.14 (14)
C6—C1—C2—C3	0.6 (2)	C7—N2—C6—C1	1.28 (14)
C1—C2—C3—C4	0.5 (2)	C6—N2—C7—N1	−1.67 (15)
C2—C3—C4—C5	−1.0 (2)	C6—N2—C7—C8	173.90 (12)
C3—C4—C5—C6	0.5 (2)	C1—N1—C7—N2	1.44 (15)
C4—C5—C6—C1	0.6 (2)	C1—N1—C7—C8	−174.19 (11)
C4—C5—C6—N2	178.86 (13)	N2—C7—C8—C9	155.35 (13)
N1—C1—C6—C5	178.17 (12)	N1—C7—C8—C9	−29.51 (18)
C2—C1—C6—C5	−1.2 (2)	C7—C8—C9—C9^i	−63.00 (19)

Symmetry code: (i) −x+1, −y+1, −z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···N2^ii	0.86	2.21	3.0431 (19)	163

Symmetry code: (ii) −x+1/2, y−1/2, z.