5,6-Di­chloro-1-propylbenz­imidazole

The title compound, C₁₀H₁₀Cl₂N₂, forms centrosymmetric head-to-tail face-to-face dimers with the n-propyl groups exo to the di­chloro­benz­imidazole groups, which are effectively planar. Within a dimer, the least-squares planes are neces­sarily parallel and exhibit an interplanar spacing of 3.412 (2) Å, which lies near the short end of the range (3.3–3.8 Å) generally accepted to indicate π–π interactions. When viewed normal to the (100) planes, the structure appears as slanted columns of dimers arranged so as to form alternating –aromatic–aliphatic– layers parallel to the (001) planes.

Key indicators

• Single-crystal X-ray study
• T = 297 K
• Mean [sigma](C-C) = 0.005 Å
• R factor = 0.064
• wR factor = 0.195
• Data-to-parameter ratio = 12.9

checkCIF/PLATON results

No syntax errors found



Alert level C
ABSTM02_ALERT_3_C  The ratio of expected to reported Tmax/Tmin(RR') is < 0.90
            Tmin and Tmax reported:      0.663     0.936
            Tmin' and Tmax expected:      0.794     0.936
            RR' =      0.835
            Please check that your absorption correction is appropriate.
PLAT029_ALERT_3_C _diffrn_measured_fraction_theta_full Low .......       0.97
PLAT061_ALERT_3_C Tmax/Tmin Range Test RR' too Large .............       0.83
PLAT094_ALERT_2_C Ratio of Maximum / Minimum Residual Density ....       2.16
PLAT220_ALERT_2_C Large Non-Solvent    C     Ueq(max)/Ueq(min) ...       2.69 Ratio
PLAT222_ALERT_3_C Large Non-Solvent    H     Ueq(max)/Ueq(min) ...       3.13 Ratio
PLAT340_ALERT_3_C Low Bond Precision on C-C bonds (x 1000) Ang ...          5

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   7 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   2 ALERT type 2 Indicator that the structure model may be wrong or deficient
   5 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

Data collection: SMART (Bruker, 2000); cell refinement: SAINT-Plus (Bruker, 2000); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPIII (Burnett & Johnson, 1996) and ORTEP-32 (Farrugia, 1997); software used to prepare material for publication: SHELXTL (Bruker, 2000).

5,6-Dichloro-1-propyl-1H-benzimidazole

Crystal data

C10H10Cl2N2	Z = 2
Mr = 229.11	F(000) = 236
Triclinic, P1	Dx = 1.392 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 6.2342 (6) Å	Cell parameters from 1011 reflections
b = 9.4516 (8) Å	θ = 3.4–25.0°
c = 9.8012 (9) Å	µ = 0.56 mm^−1
α = 104.207 (7)°	T = 297 K
β = 91.138 (8)°	Rod, colorless
γ = 101.849 (7)°	0.41 × 0.22 × 0.12 mm
V = 546.42 (9) Å^3

Data collection

Bruker SMART APEX CCD area-detector diffractometer	1905 independent reflections
Radiation source: fine-focus sealed tube	1690 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.045
ω scans	θmax = 25.1°, θmin = 2.7°
Absorption correction: multi-scan (SADABS; Blessing, 1995)	h = −7→7
Tmin = 0.663, Tmax = 0.936	k = −11→11
5615 measured reflections	l = −10→11

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.064	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.195	All H-atom parameters refined
S = 1.00	w = 1/[σ^2(Fo^2) + (0.1415P)^2 + 0.179P] where P = (Fo^2 + 2Fc^2)/3
1905 reflections	(Δ/σ)max < 0.001
148 parameters	Δρmax = 0.60 e Å^−3
0 restraints	Δρmin = −0.28 e Å^−3

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. 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 (Ų)

	x	y	z	Uiso*/Ueq
Cl15	0.18363 (14)	0.07662 (8)	0.39227 (9)	0.0632 (4)
Cl16	0.63275 (17)	0.10886 (10)	0.24992 (14)	0.0878 (5)
N11	0.5513 (4)	0.6519 (3)	0.2826 (2)	0.0459 (6)
N13	0.2228 (4)	0.6263 (3)	0.3750 (3)	0.0573 (7)
C10	0.9570 (9)	0.7665 (7)	0.0254 (5)	0.1108 (18)
H10A	0.9807	0.8728	0.0631	0.166*
H10B	0.9476	0.7435	−0.0758	0.166*
H10C	1.0773	0.7311	0.0579	0.166*
C11	0.4967 (4)	0.5068 (3)	0.2952 (3)	0.0412 (6)
C12	0.3805 (5)	0.7148 (4)	0.3314 (3)	0.0544 (8)
C13	0.2930 (4)	0.4925 (3)	0.3531 (3)	0.0440 (7)
C14	0.1950 (5)	0.3600 (3)	0.3846 (3)	0.0464 (7)
C15	0.3019 (5)	0.2436 (3)	0.3526 (3)	0.0449 (7)
C16	0.5041 (5)	0.2589 (3)	0.2915 (3)	0.0501 (7)
C17	0.6058 (5)	0.3909 (3)	0.2630 (3)	0.0482 (7)
C18	0.7521 (5)	0.7248 (4)	0.2318 (3)	0.0503 (7)
C19	0.7480 (7)	0.6922 (5)	0.0736 (4)	0.0811 (11)
H19A	0.7236	0.5850	0.0343	0.097*
H19B	0.6265	0.7264	0.0386	0.097*
H12	0.392 (6)	0.814 (5)	0.336 (4)	0.064 (10)*
H14	0.066 (7)	0.346 (4)	0.420 (4)	0.077 (12)*
H17	0.730 (6)	0.395 (4)	0.228 (4)	0.062 (10)*
H18A	0.869 (5)	0.694 (4)	0.268 (3)	0.053 (8)*
H18B	0.773 (5)	0.829 (4)	0.283 (3)	0.053 (8)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl15	0.0666 (6)	0.0436 (5)	0.0829 (7)	0.0032 (4)	0.0168 (4)	0.0289 (4)
Cl16	0.0820 (7)	0.0511 (6)	0.1471 (11)	0.0323 (5)	0.0489 (7)	0.0386 (6)
N11	0.0470 (13)	0.0422 (13)	0.0554 (13)	0.0095 (10)	0.0080 (11)	0.0249 (10)
N13	0.0527 (14)	0.0513 (15)	0.0787 (18)	0.0204 (12)	0.0172 (13)	0.0280 (13)
C10	0.109 (4)	0.139 (4)	0.068 (2)	−0.019 (3)	0.027 (3)	0.034 (3)
C11	0.0430 (14)	0.0427 (15)	0.0415 (13)	0.0074 (11)	0.0041 (11)	0.0189 (11)
C12	0.0577 (18)	0.0460 (17)	0.0701 (19)	0.0186 (14)	0.0114 (15)	0.0280 (15)
C13	0.0413 (14)	0.0468 (15)	0.0478 (14)	0.0107 (12)	0.0056 (11)	0.0182 (12)
C14	0.0406 (15)	0.0518 (17)	0.0497 (15)	0.0069 (13)	0.0111 (13)	0.0203 (13)
C15	0.0461 (14)	0.0403 (15)	0.0489 (15)	0.0042 (11)	0.0062 (12)	0.0165 (12)
C16	0.0550 (16)	0.0388 (15)	0.0609 (17)	0.0147 (12)	0.0104 (13)	0.0164 (13)
C17	0.0425 (15)	0.0490 (17)	0.0586 (17)	0.0119 (12)	0.0182 (13)	0.0210 (13)
C18	0.0511 (17)	0.0468 (17)	0.0564 (17)	0.0039 (13)	0.0061 (13)	0.0247 (14)
C19	0.078 (2)	0.098 (3)	0.058 (2)	−0.007 (2)	0.0105 (17)	0.026 (2)

Geometric parameters (Å, º)

Cl15—C15	1.738 (3)	C10—C19	1.492 (6)
Cl16—C16	1.737 (3)	C10—H10A	0.9600
N11—C12	1.363 (4)	C10—H10B	0.9600
N13—C12	1.305 (4)	C10—H10C	0.9600
N11—C11	1.380 (3)	C12—H12	0.92 (4)
N13—C13	1.391 (4)	C14—H14	0.88 (4)
C11—C13	1.396 (4)	C17—H17	0.85 (4)
C13—C14	1.385 (4)	C18—C19	1.503 (5)
C14—C15	1.375 (4)	C18—H18A	0.93 (3)
C15—C16	1.403 (4)	C18—H18B	0.97 (3)
C16—C17	1.375 (4)	C19—H19A	0.9700
C11—C17	1.381 (4)	C19—H19B	0.9700
N11—C18	1.459 (4)
C12—N11—C11	105.5 (2)	C14—C15—C16	121.1 (3)
C12—N11—C18	126.9 (3)	C14—C15—Cl15	118.7 (2)
C11—N11—C18	127.5 (2)	C16—C15—Cl15	120.2 (2)
C12—N13—C13	103.9 (3)	C17—C16—C15	121.7 (3)
C19—C10—H10A	109.5	C17—C16—Cl16	118.3 (2)
C19—C10—H10B	109.5	C15—C16—Cl16	120.0 (2)
H10A—C10—H10B	109.5	C16—C17—C11	116.6 (3)
C19—C10—H10C	109.5	C16—C17—H17	118 (2)
H10A—C10—H10C	109.5	C11—C17—H17	126 (2)
H10B—C10—H10C	109.5	N11—C18—C19	113.5 (3)
N11—C11—C17	131.8 (3)	N11—C18—H18A	107 (2)
N11—C11—C13	105.7 (2)	C19—C18—H18A	111 (2)
C17—C11—C13	122.5 (3)	N11—C18—H18B	104.1 (19)
N13—C12—N11	114.8 (3)	C19—C18—H18B	116.7 (19)
N13—C12—H12	127 (2)	H18A—C18—H18B	104 (3)
N11—C12—H12	118 (2)	C10—C19—C18	112.0 (3)
C14—C13—N13	129.6 (3)	C10—C19—H19A	109.2
C14—C13—C11	120.3 (3)	C18—C19—H19A	109.2
N13—C13—C11	110.1 (2)	C10—C19—H19B	109.2
C15—C14—C13	117.7 (3)	C18—C19—H19B	109.2
C15—C14—H14	119 (3)	H19A—C19—H19B	107.9
C13—C14—H14	123 (3)
C12—N11—C11—C17	−179.8 (3)	C11—C13—C14—C15	−2.0 (4)
C18—N11—C11—C17	−1.4 (5)	C13—C14—C15—C16	0.6 (4)
C12—N11—C11—C13	−0.5 (3)	C13—C14—C15—Cl15	179.5 (2)
C18—N11—C11—C13	177.9 (3)	C14—C15—C16—C17	1.1 (5)
C13—N13—C12—N11	−0.3 (4)	Cl15—C15—C16—C17	−177.9 (2)
C11—N11—C12—N13	0.5 (4)	C14—C15—C16—Cl16	−179.0 (2)
C18—N11—C12—N13	−177.9 (3)	Cl15—C15—C16—Cl16	2.1 (4)
C12—N13—C13—C14	177.5 (3)	C15—C16—C17—C11	−1.2 (4)
C12—N13—C13—C11	−0.1 (3)	Cl16—C16—C17—C11	178.9 (2)
N11—C11—C13—C14	−177.5 (2)	N11—C11—C17—C16	178.9 (3)
C17—C11—C13—C14	1.9 (4)	C13—C11—C17—C16	−0.3 (4)
N11—C11—C13—N13	0.4 (3)	C12—N11—C18—C19	−99.2 (4)
C17—C11—C13—N13	179.8 (3)	C11—N11—C18—C19	82.7 (4)
N13—C13—C14—C15	−179.4 (3)	N11—C18—C19—C10	−179.1 (4)