(S,S)-1,2-Bis(1-methyl­benzimidazol-2-yl)-1′,2′-bis­(methoxy)ethane

The title compound, C₂₀H₂₂N₄O₂, exhibits twofold site symmetry and adopts a stepped or kinked conformation in the solid state, with the approximately planar N-methyl benz­imidazole fragments corresponding to the run and the 1′,2′-bis­(methoxy)ethane fragment to the rise. When viewed along the b axis, the mol­ecules stack in a herringbone pattern as layers along a. Intermolecular distances suggest that the mol­ecules are held in the lattice largely by C—H...π interactions with little, if any, π...π bonding. Examination of the displacement parameters suggests that the mol­ecules librate about axes approximately parallel to the a axis and passing near the center of mass of the mol­ecules. Bond distances in the imidazole group lie within one s.u. of the average reported for 19 structures containing comparable benz­imidazole fragments.

Key indicators

• Single-crystal X-ray study
• T = 296 K
• Mean [sigma](C-C) = 0.006 Å
• R factor = 0.048
• wR factor = 0.120
• Data-to-parameter ratio = 11.5

checkCIF/PLATON results

No syntax errors found



Alert level B
ABSTM02_ALERT_3_B  The ratio of expected to reported Tmax/Tmin(RR') is < 0.75
            Tmin and Tmax reported:      0.684     0.998
            Tmin' and Tmax expected:      0.959     0.998
            RR' =      0.713
            Please check that your absorption correction is appropriate.
PLAT061_ALERT_3_B Tmax/Tmin Range Test RR' too Large .............       0.71

Alert level C
PLAT024_ALERT_4_C Merging of Friedel Data Preferred for Z<=Si ....          !
PLAT029_ALERT_3_C _diffrn_measured_fraction_theta_full Low .......       0.99
PLAT220_ALERT_2_C Large Non-Solvent    C     Ueq(max)/Ueq(min) ...       2.51 Ratio
PLAT222_ALERT_3_C Large Non-Solvent    H     Ueq(max)/Ueq(min) ...       3.05 Ratio
PLAT340_ALERT_3_C Low Bond Precision on C-C bonds (x 1000) Ang ...          6

Alert level G
REFLT03_ALERT_4_G  ALERT: MoKa measured Friedel data cannot be used to
                   determine absolute structure in a light-atom
                   study EXCEPT under VERY special conditions.
                   It is preferred that Friedel data is merged in such cases.
           From the CIF: _diffrn_reflns_theta_max           25.10
           From the CIF: _reflns_number_total               1607
           Count of symmetry unique reflns          973
           Completeness (_total/calc)            165.16%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured       634
           Fraction of Friedel pairs measured     0.652
           Are heavy atom types Z>Si present           no

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

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 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
   2 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

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

(S,S)-1,2-bis(1-hydrobenzimidazol-2-yl)-1,2-ethanediol

Crystal data

C20H22N4O2	Dx = 1.239 Mg m^−3
Mr = 350.41	Melting point: 146-147 ^oC K
Orthorhombic, C2221	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: C 2c 2	Cell parameters from 664 reflections
a = 6.7980 (6) Å	θ = 3.5–22.8°
b = 10.9084 (9) Å	µ = 0.08 mm^−1
c = 25.331 (2) Å	T = 296 K
V = 1878.4 (3) Å^3	Plate, colorless
Z = 4	0.50 × 0.45 × 0.03 mm
F(000) = 744

Data collection

Bruker CCD area detector diffractometer	1607 independent reflections
Radiation source: fine-focus sealed tube	1228 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.032
φ and ω scans	θmax = 25.1°, θmin = 3.2°
Absorption correction: multi-scan (SADABS, Blessing, 1995)	h = −7→8
Tmin = 0.684, Tmax = 0.998	k = −12→12
3653 measured reflections	l = −30→29

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)] = 0.048	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.120	w = 1/[σ^2(Fo^2) + (0.0665P)^2 + 0.3025P] where P = (Fo^2 + 2Fc^2)/3
S = 1.00	(Δ/σ)max < 0.001
1607 reflections	Δρmax = 0.13 e Å^−3
140 parameters	Δρmin = −0.12 e Å^−3
0 restraints	Absolute structure: Flack (1983)
Primary atom site location: structure-invariant direct methods

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
N13	0.1034 (3)	0.8534 (3)	0.15061 (9)	0.0544 (6)
N11	0.1330 (3)	0.6485 (3)	0.15224 (9)	0.0528 (6)
C12	0.0586 (3)	0.7520 (3)	0.17554 (9)	0.0453 (6)
C1	−0.0632 (3)	0.7514 (3)	0.22506 (9)	0.0455 (6)
O1	−0.1995 (2)	0.65471 (19)	0.22694 (7)	0.0549 (5)
C11	0.2369 (4)	0.6885 (4)	0.10867 (11)	0.0602 (9)
C13	0.2181 (4)	0.8163 (4)	0.10822 (10)	0.0603 (9)
C17	0.3457 (5)	0.6257 (5)	0.07106 (15)	0.0887 (14)
C2	−0.3528 (4)	0.6667 (3)	0.18888 (12)	0.0700 (9)
H2A	−0.4317	0.7371	0.1972	0.105*
H2B	−0.4336	0.5946	0.1894	0.105*
H2C	−0.2964	0.6766	0.1544	0.105*
C18	0.1200 (5)	0.5205 (3)	0.16879 (12)	0.0692 (9)
H18A	0.1295	0.5158	0.2066	0.104*
H18B	0.2254	0.4747	0.1531	0.104*
H18C	−0.0037	0.4869	0.1576	0.104*
C15	0.4206 (6)	0.8229 (9)	0.03198 (16)	0.1101 (18)
C14	0.3107 (6)	0.8855 (5)	0.06901 (14)	0.0856 (13)
C16	0.4373 (7)	0.6962 (8)	0.03325 (18)	0.114 (2)
H16	0.513 (7)	0.660 (5)	0.0053 (18)	0.125 (14)*
H14	0.301 (5)	0.974 (3)	0.0688 (15)	0.075 (12)*
H15	0.487 (6)	0.884 (4)	0.0056 (18)	0.116 (15)*
H17	0.365 (5)	0.539 (4)	0.0736 (15)	0.076 (11)*
H1	−0.128 (3)	0.830 (3)	0.2246 (9)	0.041 (6)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N13	0.0551 (12)	0.0536 (16)	0.0545 (12)	−0.0028 (13)	−0.0038 (11)	0.0041 (13)
N11	0.0517 (11)	0.0524 (15)	0.0542 (12)	0.0077 (13)	−0.0090 (10)	−0.0107 (13)
C12	0.0429 (11)	0.0418 (14)	0.0514 (11)	0.0003 (15)	−0.0078 (10)	−0.0008 (17)
C1	0.0434 (11)	0.0357 (13)	0.0576 (12)	0.0025 (15)	−0.0043 (11)	−0.0010 (17)
O1	0.0464 (9)	0.0550 (12)	0.0633 (9)	−0.0084 (10)	−0.0123 (9)	0.0067 (10)
C11	0.0454 (14)	0.086 (3)	0.0491 (15)	0.0104 (16)	−0.0103 (13)	−0.0098 (18)
C13	0.0479 (14)	0.084 (3)	0.0491 (15)	−0.0029 (18)	−0.0081 (13)	0.0064 (18)
C17	0.066 (2)	0.132 (5)	0.068 (2)	0.032 (3)	−0.0049 (19)	−0.028 (3)
C2	0.0530 (15)	0.079 (2)	0.0783 (18)	−0.0068 (17)	−0.0218 (14)	0.0015 (19)
C18	0.0752 (18)	0.0431 (18)	0.089 (2)	0.0133 (16)	−0.0199 (16)	−0.0145 (16)
C15	0.063 (2)	0.206 (6)	0.061 (2)	−0.002 (4)	0.007 (2)	0.023 (4)
C14	0.069 (2)	0.125 (4)	0.062 (2)	−0.014 (2)	−0.0101 (19)	0.021 (2)
C16	0.072 (2)	0.211 (7)	0.060 (2)	0.035 (4)	0.006 (2)	−0.015 (4)

Geometric parameters (Å, º)

N13—C12	1.310 (4)	C17—C16	1.377 (8)
N13—C13	1.387 (4)	C17—H17	0.95 (4)
N11—C12	1.371 (4)	C2—H2A	0.9600
N11—C11	1.381 (4)	C2—H2B	0.9600
C11—C13	1.400 (4)	C2—H2C	0.9600
N11—C18	1.460 (4)	C18—H18A	0.9600
C12—C1	1.503 (3)	C18—H18B	0.9600
C1—O1	1.404 (3)	C18—H18C	0.9600
C1—C1^i	1.528 (4)	C15—C14	1.380 (7)
C1—H1	0.96 (3)	C15—C16	1.387 (8)
O1—C2	1.426 (3)	C15—H15	1.04 (5)
C11—C17	1.387 (4)	C14—H14	0.97 (3)
C13—C14	1.397 (5)	C16—H16	0.96 (5)
C12—N13—C13	104.9 (3)	C11—C17—H17	121 (2)
C12—N11—C11	105.8 (3)	O1—C2—H2A	109.5
C12—N11—C18	129.9 (2)	O1—C2—H2B	109.5
C11—N11—C18	124.3 (3)	H2A—C2—H2B	109.5
N13—C12—N11	113.7 (2)	O1—C2—H2C	109.5
N13—C12—C1	122.3 (3)	H2A—C2—H2C	109.5
N11—C12—C1	124.0 (3)	H2B—C2—H2C	109.5
O1—C1—C12	113.3 (2)	N11—C18—H18A	109.5
O1—C1—C1^i	110.07 (17)	N11—C18—H18B	109.5
C12—C1—C1^i	112.3 (2)	H18A—C18—H18B	109.5
O1—C1—H1	111.7 (14)	N11—C18—H18C	109.5
C12—C1—H1	103.6 (14)	H18A—C18—H18C	109.5
C1^i—C1—H1	105.5 (14)	H18B—C18—H18C	109.5
C1—O1—C2	113.0 (2)	C14—C15—C16	121.5 (5)
N11—C11—C17	131.7 (4)	C14—C15—H15	111 (3)
N11—C11—C13	105.9 (3)	C16—C15—H15	128 (2)
C17—C11—C13	122.3 (4)	C15—C14—C13	117.4 (5)
N13—C13—C14	130.2 (4)	C15—C14—H14	122 (2)
N13—C13—C11	109.6 (3)	C13—C14—H14	121 (2)
C14—C13—C11	120.2 (4)	C17—C16—C15	122.4 (5)
C16—C17—C11	116.3 (6)	C17—C16—H16	121 (3)
C16—C17—H17	123 (2)	C15—C16—H16	116 (3)
C13—N13—C12—N11	−1.0 (3)	C18—N11—C11—C13	−177.6 (2)
C13—N13—C12—C1	178.96 (19)	C12—N13—C13—C14	−178.4 (3)
C11—N11—C12—N13	0.7 (3)	C12—N13—C13—C11	0.9 (3)
C18—N11—C12—N13	178.0 (3)	N11—C11—C13—N13	−0.4 (3)
C11—N11—C12—C1	−179.2 (2)	C17—C11—C13—N13	−179.4 (2)
C18—N11—C12—C1	−1.9 (4)	N11—C11—C13—C14	178.9 (2)
N13—C12—C1—O1	139.8 (2)	C17—C11—C13—C14	−0.1 (5)
N11—C12—C1—O1	−40.3 (3)	N11—C11—C17—C16	−177.8 (3)
N13—C12—C1—C1^i	−94.7 (2)	C13—C11—C17—C16	0.8 (5)
N11—C12—C1—C1^i	85.2 (2)	C16—C15—C14—C13	0.6 (6)
C12—C1—O1—C2	−68.1 (3)	N13—C13—C14—C15	178.5 (3)
C1^i—C1—O1—C2	165.3 (2)	C11—C13—C14—C15	−0.6 (5)
C12—N11—C11—C17	178.6 (3)	C11—C17—C16—C15	−0.9 (6)
C18—N11—C11—C17	1.1 (4)	C14—C15—C16—C17	0.2 (8)
C12—N11—C11—C13	−0.1 (3)

Symmetry code: (i) −x, y, −z+1/2.