1,1'-Butane-1,4-diylbis(1H-benzimidazole)

The mol­ecule of the title compound, C₁₈H₁₈N₄, is disposed about a center of inversion. The dihedral angle between the five- and six-membered rings is 1.23 (6)°, showing almost exact coplanarity.

Key indicators

• Single-crystal X-ray study
• T = 296 K
• Mean [sigma](C-C)= 0.002 Å
• R factor = 0.031
• wR factor = 0.085
• Data-to-parameter ratio = 17.8

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Computing details

Data collection: X-AREA (Stoe & Cie, 2002); cell refinement: X-AREA; data reduction: X-RED32 (Stoe & Cie, 2002); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).

1,1'-Butane-1,4-diylbis(1H-benzimidazole)

Crystal data

C18H18N4	F(000) = 308
Mr = 290.36	Dx = 1.272 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 11055 reflections
a = 5.6495 (4) Å	θ = 2.5–28.0°
b = 10.6323 (7) Å	µ = 0.08 mm^−1
c = 12.7814 (9) Å	T = 296 K
β = 99.042 (6)°	Prism, colourless
V = 758.20 (9) Å^3	0.43 × 0.35 × 0.27 mm
Z = 2

Data collection

Stoe IPDS-2 diffractometer	1354 reflections with I > 2σ(I)
Radiation source: sealed X-ray tube, 12 x 0.4 mm long-fine focus	Rint = 0.062
Plane graphite monochromator	θmax = 27.9°, θmin = 2.5°
Detector resolution: 6.67 pixels mm^-1	h = −7→6
ω scans	k = −13→13
11438 measured reflections	l = −16→16
1795 independent reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.031	H-atom parameters constrained
wR(F^2) = 0.085	w = 1/[σ^2(Fo^2) + (0.0449P)^2 + 0.023P] where P = (Fo^2 + 2Fc^2)/3
S = 1.04	(Δ/σ)max < 0.001
1795 reflections	Δρmax = 0.13 e Å^−3
101 parameters	Δρmin = −0.11 e Å^−3
0 restraints	Extinction correction: SHELXL97, fc^*=kfc[1+0.001xfc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.086 (8)

Special details

Experimental. ¹H NMR (CDCl₃): δ 2.37 (m, –CH₂–CH₂–, 2H), 4.69 (t, –CH₂–N, 2H), 7.83–7.98 (m, Ar–H, 4H), 8.63 (s, N–CH–N, 1H). ¹³C NMR (CDCl₃): δ 27.15, 52.13, 114.26, 123.14, 137.34 142.43. Analysis calculated for C₁₈H₁₈N₄: C 74.48, H 6.21, N 19.31%; found: C 74.52, H 6.21, N 19.43%.

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

Refinement. Refinement on F² for ALL reflections except those flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The observed criterion of F² > σ(F²) is used only for calculating -R-factor-obs 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 (Ų)

	x	y	z	Uiso*/Ueq
N1	0.48136 (15)	0.17964 (7)	0.69126 (6)	0.0532 (3)
N2	0.39719 (18)	0.19249 (9)	0.85641 (6)	0.0627 (3)
C1	0.5364 (2)	0.14428 (10)	0.79418 (8)	0.0602 (3)
C2	0.23568 (19)	0.26504 (9)	0.78921 (7)	0.0533 (3)
C3	0.0445 (2)	0.33833 (10)	0.81037 (8)	0.0636 (3)
C4	−0.0839 (2)	0.40365 (10)	0.72842 (10)	0.0686 (4)
C5	−0.0281 (2)	0.39835 (10)	0.62576 (9)	0.0660 (4)
C6	0.1589 (2)	0.32610 (9)	0.60215 (8)	0.0578 (3)
C7	0.28726 (18)	0.25912 (8)	0.68555 (7)	0.0489 (3)
C8	0.5877 (2)	0.13255 (9)	0.60193 (8)	0.0571 (3)
C9	0.44837 (18)	0.02256 (9)	0.54801 (7)	0.0527 (3)
H1	0.66270	0.09030	0.81850	0.0720*
H3	0.00540	0.34270	0.87830	0.0760*
H4	−0.21210	0.45300	0.74130	0.0820*
H5	−0.11920	0.44460	0.57220	0.0790*
H6	0.19710	0.32240	0.53400	0.0690*
H8A	0.75140	0.10650	0.62690	0.0690*
H8B	0.59200	0.19980	0.55100	0.0690*
H9A	0.28280	0.04750	0.52620	0.0630*
H9B	0.45060	−0.04610	0.59810	0.0630*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.0630 (5)	0.0523 (4)	0.0463 (4)	−0.0016 (4)	0.0151 (3)	−0.0082 (3)
N2	0.0781 (7)	0.0670 (5)	0.0439 (4)	0.0001 (4)	0.0124 (4)	−0.0035 (4)
C1	0.0689 (7)	0.0593 (6)	0.0520 (5)	0.0017 (5)	0.0079 (5)	−0.0029 (4)
C2	0.0657 (6)	0.0521 (5)	0.0443 (4)	−0.0066 (4)	0.0155 (4)	−0.0079 (4)
C3	0.0744 (7)	0.0657 (6)	0.0559 (5)	−0.0027 (5)	0.0260 (5)	−0.0112 (5)
C4	0.0701 (7)	0.0626 (6)	0.0771 (7)	0.0061 (5)	0.0240 (6)	−0.0058 (5)
C5	0.0732 (7)	0.0596 (6)	0.0656 (6)	0.0028 (5)	0.0126 (5)	0.0047 (5)
C6	0.0724 (7)	0.0567 (5)	0.0459 (5)	−0.0053 (5)	0.0144 (4)	−0.0025 (4)
C7	0.0590 (6)	0.0446 (4)	0.0453 (4)	−0.0059 (4)	0.0149 (4)	−0.0076 (3)
C8	0.0633 (6)	0.0573 (5)	0.0552 (5)	−0.0036 (4)	0.0231 (5)	−0.0097 (4)
C9	0.0616 (6)	0.0506 (5)	0.0493 (5)	0.0002 (4)	0.0194 (4)	−0.0044 (4)

Geometric parameters (Å, º)

N1—C1	1.3564 (13)	C8—C9	1.5138 (14)
N1—C7	1.3772 (13)	C9—C9^i	1.5171 (13)
N1—C8	1.4597 (13)	C1—H1	0.9300
N2—C1	1.3079 (14)	C3—H3	0.9300
N2—C2	1.3853 (13)	C4—H4	0.9300
C2—C3	1.3924 (15)	C5—H5	0.9300
C2—C7	1.4020 (13)	C6—H6	0.9300
C3—C4	1.3663 (16)	C8—H8A	0.9700
C4—C5	1.3980 (17)	C8—H8B	0.9700
C5—C6	1.3775 (16)	C9—H9A	0.9700
C6—C7	1.3879 (14)	C9—H9B	0.9700
N1···C4^ii	3.4006 (14)	H1···C5^viii	2.9100
N2···H9B^iii	2.9400	H3···H9A^iv	2.5400
N2···H6^iv	2.6900	H4···C1^vii	2.7300
N2···H8B^iv	2.8000	H6···C8	3.0200
C1···C3^ii	3.5147 (16)	H6···H8B	2.5600
C1···C4^v	3.5961 (16)	H6···N2^ix	2.6900
C3···C1^vi	3.5147 (16)	H8A···H1	2.5800
C4···N1^vi	3.4006 (14)	H8A···H9A^i	2.5400
C4···C1^vii	3.5961 (16)	H8B···C5^ii	3.0500
C5···C8^vi	3.5472 (15)	H8B···C6	2.9500
C8···C5^ii	3.5472 (15)	H8B···H6	2.5600
C1···H4^v	2.7300	H8B···H9B^i	2.4900
C2···H9B^iii	2.9100	H8B···N2^ix	2.8000
C5···H8B^vi	3.0500	H9A···C7	3.0300
C5···H1^iii	2.9100	H9A···H8A^i	2.5400
C6···H8B	2.9500	H9A···H3^ix	2.5400
C7···H9A	3.0300	H9B···N2^viii	2.9400
C8···H6	3.0200	H9B···C2^viii	2.9100
H1···H8A	2.5800	H9B···H8B^i	2.4900
C1—N1—C7	106.30 (8)	C2—C3—H3	121.00
C1—N1—C8	127.13 (9)	C4—C3—H3	121.00
C7—N1—C8	126.24 (8)	C3—C4—H4	119.00
C1—N2—C2	103.98 (8)	C5—C4—H4	119.00
N1—C1—N2	114.40 (9)	C4—C5—H5	119.00
N2—C2—C3	130.29 (9)	C6—C5—H5	119.00
N2—C2—C7	110.27 (9)	C5—C6—H6	122.00
C3—C2—C7	119.44 (9)	C7—C6—H6	122.00
C2—C3—C4	118.04 (10)	N1—C8—H8A	109.00
C3—C4—C5	121.88 (10)	N1—C8—H8B	109.00
C4—C5—C6	121.46 (10)	C9—C8—H8A	109.00
C5—C6—C7	116.36 (10)	C9—C8—H8B	109.00
N1—C7—C2	105.04 (8)	H8A—C8—H8B	108.00
N1—C7—C6	132.15 (9)	C8—C9—H9A	109.00
C2—C7—C6	122.80 (9)	C8—C9—H9B	109.00
N1—C8—C9	111.88 (9)	H9A—C9—H9B	108.00
C8—C9—C9^i	111.96 (8)	C9^i—C9—H9A	109.00
N1—C1—H1	123.00	C9^i—C9—H9B	109.00
N2—C1—H1	123.00
C7—N1—C1—N2	0.16 (12)	N2—C2—C7—C6	−177.86 (9)
C8—N1—C1—N2	−173.59 (9)	N2—C2—C3—C4	178.38 (11)
C8—N1—C7—C2	173.15 (9)	C7—C2—C3—C4	−0.99 (15)
C1—N1—C7—C6	177.99 (11)	C3—C2—C7—N1	−179.56 (9)
C8—N1—C7—C6	−8.19 (16)	C3—C2—C7—C6	1.63 (15)
C1—N1—C8—C9	92.02 (12)	C2—C3—C4—C5	0.03 (17)
C7—N1—C8—C9	−80.54 (11)	C3—C4—C5—C6	0.40 (17)
C1—N1—C7—C2	−0.66 (10)	C4—C5—C6—C7	0.17 (16)
C2—N2—C1—N1	0.43 (12)	C5—C6—C7—C2	−1.18 (15)
C1—N2—C2—C3	179.74 (11)	C5—C6—C7—N1	−179.64 (10)
C1—N2—C2—C7	−0.85 (12)	N1—C8—C9—C9^i	177.28 (8)
N2—C2—C7—N1	0.96 (11)	C8—C9—C9^i—C8^i	179.98 (10)

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