1,4-Bis(1H-benzimidazol-1-yl)benzene

Sun, G.-F.; Hu, J.-P.; Tang, D.-Y.; Zhang, Y.-Q.

doi:10.1107/S1600536811031278

organic compounds

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ISSN: 2056-9890

Volume 67| Part 9| September 2011| Page o2286

doi:10.1107/S1600536811031278

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1,4-Bis(1H-benzimidazol-1-yl)benzene

Guo-Feng Sun,^a ^* Jian-Ping Hu,^a Dian-Yong Tang ^a and Yuan-Qin Zhang ^a

^aMolecular Design Center, College of Chemistry and Life Science, Leshan Normal University, Leshan 614000, Sichuan Province, People's Republic of China
^*Correspondence e-mail: sunguofeng03@163.com

(Received 28 July 2011; accepted 3 August 2011; online 11 August 2011)

In the title compound, C₂₀H₁₄N₄, the dihedral angles between the central benzene ring and the pendant benzimidazole ring systems are 46.60 (15) and 47.89 (16)°. The dihedral angle between the benzimidazole ring systems is 85.62 (12)° and the N atoms lie to the same side of the molecule. In the crystal, molecules are linked by C—H⋯N interactions and weak aromatic π–π stacking [shortest centroid–centroid separation = 3.770 (2) Å] is observed.

Related literature

For background to benzimidazole derivatives as ligands in crystal engineering, see: Li et al. (2009 ); Vijayan et al. (2006 ).

Experimental

Crystal data

C₂₀H₁₄N₄
M_r = 310.35
Orthorhombic, P n a 2₁
a = 9.5458 (19) Å
b = 20.499 (4) Å
c = 7.9283 (16) Å
V = 1551.4 (5) Å³
Z = 4
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 293 K
0.25 × 0.22 × 0.18 mm

Data collection

Rigaku Mercury CCD diffractometer
Absorption correction: multi-scan (CrystalClear; Rigaku/MSC, 2005 ) T_min = 0.980, T_max = 0.985
12744 measured reflections
1479 independent reflections
1298 reflections with I > 2σ(I)
R_int = 0.075

Refinement

R[F² > 2σ(F²)] = 0.051
wR(F²) = 0.104
S = 1.17
1479 reflections
231 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 0.14 e Å⁻³
Δρ_min = −0.16 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C1—H1⋯N4ⁱ	0.93	2.50	3.359 (5)	153
C6—H6⋯N4ⁱⁱ	0.93	2.56	3.447 (5)	159
Symmetry codes: (i) x-1, y, z; (ii) $[-x+2, -y+1, z-{\script{1\over 2}}]$ .

Data collection: CrystalClear (Rigaku/MSC, 2005); cell refinement: CrystalClear; data reduction: CrystalClear; 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).

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811031278/hb6340sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536811031278/hb6340Isup2.hkl

Supporting information file. DOI: 10.1107/S1600536811031278/hb6340Isup3.cml

checkCIF report

Comment top

In recent years, benzimidazole has been well used in crystal engineering, because they exhibit a strong networking ability (Vijayan et al., 2006). To our knowledge, the research on benzimidazole ligands bearing rigid spacers is still less developed (Li et al., 2009), and the title compound was well designed for building polymer architecture. We report here the structure and conformation of a rigid benzimidazole derivative, and further explore the ligand coordination. As shown in Fig. 1, the title compound is trans-conformation and tends to trans-coordination. The molecule has no inversion centre because two benzimidazole rings are not coplanar.

Related literature top

For background to benzimidazole derivatives as ligands in crystal engineering, see: Li et al. (2009); Vijayan et al. (2006).

Experimental top

The ligand 1,4-di(1H-benzimidazol-1-yl)benzene was prepared by a modified method (Li et al., 2009). A mixture of 1,4-dibromophenyl (3.72 g, 12.0 mmol), benzimidazole (4.25 g, 36.0 mmol), CuI (0.38 g, 2.0 mmol), 1,10-phenanthroline (0.72 g, 4.0 mmol), and Cs₂CO₃ (2.48 g, 18.0 mmol) was suspended in DMF (50 ml) and refluxed for 48 h to afford (I) as off-white powder, yield: 25% (based on 1,4-dibromophenyl), Mp: 291°C. Colourless blocks of (I) were obtained by recrystallizing from a mixed solvent of methanol and water (1:1).

Computing details top

Data collection: CrystalClear (Rigaku/MSC, 2005); cell refinement: CrystalClear (Rigaku/MSC, 2005); data reduction: CrystalClear (Rigaku/MSC, 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

	Fig. 1. The molecular structure of (I). Displacement ellipsoids are drawn at the 30% probability level and H atoms are shown as small spheres of arbitrary radius.
	Fig. 2. The crystal packing for (I).

1,4-Bis(1H-benzimidazol-1-yl)benzene top

Crystal data top

C₂₀H₁₄N₄	D_x = 1.329 Mg m⁻³
M_r = 310.35	Melting point: 564 K
Orthorhombic, Pna2₁	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2n	Cell parameters from 13068 reflections
a = 9.5458 (19) Å	θ = 3.3–27.6°
b = 20.499 (4) Å	µ = 0.08 mm⁻¹
c = 7.9283 (16) Å	T = 293 K
V = 1551.4 (5) Å³	Block, colorless
Z = 4	0.25 × 0.22 × 0.18 mm
F(000) = 648

Data collection top

Rigaku Mercury CCD diffractometer	1479 independent reflections
Radiation source: fine-focus sealed tube	1298 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.075
Detector resolution: 9 pixels mm^-1	θ_max = 25.0°, θ_min = 3.5°
ω scans	h = −11→11
Absorption correction: multi-scan (CrystalClear; Rigaku/MSC, 2005)	k = −24→24
T_min = 0.980, T_max = 0.985	l = −9→9
12744 measured reflections

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.051	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.104	H-atom parameters constrained
S = 1.17	w = 1/[σ²(F_o²) + (0.0488P)² + 0.1271P] where P = (F_o² + 2F_c²)/3
1479 reflections	(Δ/σ)_max < 0.001
231 parameters	Δρ_max = 0.14 e Å⁻³
1 restraint	Δρ_min = −0.16 e Å⁻³
0 constraints

Crystal data top

C₂₀H₁₄N₄	V = 1551.4 (5) Å³
M_r = 310.35	Z = 4
Orthorhombic, Pna2₁	Mo Kα radiation
a = 9.5458 (19) Å	µ = 0.08 mm⁻¹
b = 20.499 (4) Å	T = 293 K
c = 7.9283 (16) Å	0.25 × 0.22 × 0.18 mm

Data collection top

Rigaku Mercury CCD diffractometer	1479 independent reflections
Absorption correction: multi-scan (CrystalClear; Rigaku/MSC, 2005)	1298 reflections with I > 2σ(I)
T_min = 0.980, T_max = 0.985	R_int = 0.075
12744 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.051	1 restraint
wR(F²) = 0.104	H-atom parameters constrained
S = 1.17	Δρ_max = 0.14 e Å⁻³
1479 reflections	Δρ_min = −0.16 e Å⁻³
231 parameters

Special details top

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 (Å²) top

	x	y	z	U_iso*/U_eq
N1	0.2140 (3)	0.55131 (15)	0.6320 (4)	0.0462 (8)
N2	0.4461 (3)	0.53457 (14)	0.6010 (4)	0.0411 (8)
N3	0.9643 (3)	0.40659 (14)	0.6681 (4)	0.0383 (7)
N4	1.1632 (3)	0.37523 (15)	0.7980 (4)	0.0479 (9)
C1	0.3178 (4)	0.51125 (18)	0.6527 (5)	0.0452 (9)
H1	0.3065	0.4699	0.6993	0.043 (10)*
C2	0.2750 (3)	0.60700 (16)	0.5602 (4)	0.0361 (8)
C3	0.2141 (4)	0.66544 (17)	0.5108 (5)	0.0427 (9)
H3	0.1189	0.6729	0.5263	0.036 (9)*
C4	0.2986 (4)	0.71179 (17)	0.4385 (5)	0.0421 (9)
H4	0.2598	0.7513	0.4047	0.063 (13)*
C5	0.4412 (4)	0.70086 (17)	0.4146 (5)	0.0442 (10)
H5	0.4948	0.7331	0.3629	0.046 (11)*
C6	0.5059 (4)	0.64388 (17)	0.4649 (5)	0.0431 (9)
H6	0.6014	0.6371	0.4499	0.045 (10)*
C7	0.4197 (3)	0.59693 (16)	0.5399 (5)	0.0364 (8)
C8	0.5788 (3)	0.50222 (17)	0.6151 (4)	0.0379 (9)
C9	0.5905 (4)	0.43768 (17)	0.5667 (5)	0.0419 (9)
H9	0.5134	0.4158	0.5226	0.058 (12)*
C10	0.7177 (3)	0.40549 (17)	0.5842 (5)	0.0408 (9)
H10	0.7256	0.3618	0.5539	0.037 (9)*
C11	0.8327 (3)	0.43899 (17)	0.6469 (5)	0.0366 (8)
C12	0.8204 (4)	0.50358 (17)	0.6927 (5)	0.0421 (9)
H12	0.8982	0.5260	0.7330	0.047 (11)*
C13	0.6930 (4)	0.53532 (18)	0.6794 (5)	0.0455 (10)
H13	0.6843	0.5786	0.7130	0.037 (10)*
C14	1.0470 (4)	0.40901 (19)	0.8087 (5)	0.0443 (9)
H14	1.0229	0.4329	0.9042	0.046 (11)*
C15	1.0353 (3)	0.36720 (16)	0.5527 (5)	0.0391 (9)
C16	1.0063 (4)	0.3484 (2)	0.3891 (6)	0.0523 (11)
H16	0.9241	0.3610	0.3355	0.064 (13)*
C17	1.1043 (4)	0.3103 (2)	0.3088 (6)	0.0662 (12)
H17	1.0880	0.2971	0.1983	0.086 (16)*
C18	1.2279 (5)	0.2907 (2)	0.3899 (6)	0.0650 (13)
H18	1.2914	0.2644	0.3325	0.055 (12)*
C19	1.2571 (4)	0.30983 (19)	0.5533 (6)	0.0525 (10)
H19	1.3397	0.2973	0.6065	0.065 (13)*
C20	1.1584 (4)	0.34847 (17)	0.6357 (5)	0.0423 (9)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
N1	0.0327 (17)	0.0505 (18)	0.056 (2)	0.0003 (15)	0.0048 (16)	0.0058 (17)
N2	0.0318 (16)	0.0426 (18)	0.049 (2)	0.0027 (13)	0.0035 (15)	0.0057 (15)
N3	0.0292 (15)	0.0410 (16)	0.0448 (18)	0.0019 (13)	−0.0052 (14)	0.0046 (16)
N4	0.040 (2)	0.058 (2)	0.046 (2)	0.0025 (16)	−0.0089 (16)	0.0052 (18)
C1	0.041 (2)	0.038 (2)	0.057 (2)	−0.0039 (17)	0.010 (2)	0.009 (2)
C2	0.0285 (17)	0.0417 (19)	0.038 (2)	−0.0029 (16)	0.0033 (17)	−0.0012 (17)
C3	0.034 (2)	0.047 (2)	0.047 (2)	0.0072 (17)	0.0010 (17)	−0.0050 (19)
C4	0.039 (2)	0.0353 (18)	0.052 (2)	0.0059 (17)	0.0013 (19)	0.0000 (19)
C5	0.044 (2)	0.038 (2)	0.051 (2)	−0.0019 (18)	0.0041 (19)	0.003 (2)
C6	0.031 (2)	0.047 (2)	0.052 (2)	−0.0003 (17)	0.0011 (19)	−0.0041 (19)
C7	0.0305 (18)	0.0354 (19)	0.043 (2)	0.0001 (15)	0.0014 (17)	−0.0035 (19)
C8	0.0363 (19)	0.041 (2)	0.036 (2)	0.0057 (15)	0.0021 (16)	0.0033 (17)
C9	0.0316 (19)	0.042 (2)	0.052 (2)	−0.0021 (16)	−0.0049 (18)	0.0017 (19)
C10	0.039 (2)	0.038 (2)	0.046 (2)	0.0017 (17)	−0.0042 (17)	−0.0015 (18)
C11	0.0318 (19)	0.044 (2)	0.0339 (19)	0.0024 (15)	−0.0022 (17)	0.0042 (18)
C12	0.034 (2)	0.043 (2)	0.049 (2)	−0.0014 (17)	−0.0066 (17)	−0.0030 (19)
C13	0.044 (2)	0.039 (2)	0.054 (3)	0.0039 (17)	−0.0021 (19)	−0.0105 (19)
C14	0.039 (2)	0.053 (2)	0.041 (2)	−0.0013 (19)	−0.0063 (19)	0.001 (2)
C15	0.0338 (19)	0.0346 (18)	0.049 (2)	0.0030 (15)	−0.0013 (18)	0.0040 (18)
C16	0.048 (2)	0.061 (3)	0.048 (2)	0.013 (2)	−0.013 (2)	−0.007 (2)
C17	0.064 (3)	0.079 (3)	0.056 (3)	0.024 (2)	−0.004 (2)	−0.015 (3)
C18	0.057 (3)	0.068 (3)	0.070 (3)	0.024 (2)	0.003 (2)	−0.010 (3)
C19	0.042 (2)	0.056 (2)	0.060 (3)	0.011 (2)	−0.005 (2)	0.006 (2)
C20	0.037 (2)	0.041 (2)	0.049 (2)	0.0012 (16)	−0.0034 (19)	0.005 (2)

Geometric parameters (Å, º) top

N1—C1	1.298 (5)	C8—C13	1.381 (5)
N1—C2	1.402 (4)	C8—C9	1.382 (5)
N2—C1	1.377 (4)	C9—C10	1.389 (5)
N2—C7	1.390 (4)	C9—H9	0.9300
N2—C8	1.434 (4)	C10—C11	1.387 (5)
N3—C14	1.367 (4)	C10—H10	0.9301
N3—C15	1.396 (5)	C11—C12	1.378 (5)
N3—C11	1.431 (4)	C12—C13	1.384 (5)
N4—C14	1.310 (4)	C12—H12	0.9299
N4—C20	1.400 (5)	C13—H13	0.9301
C1—H1	0.9301	C14—H14	0.9299
C2—C3	1.388 (5)	C15—C16	1.381 (6)
C2—C7	1.406 (4)	C15—C20	1.400 (5)
C3—C4	1.372 (5)	C16—C17	1.374 (6)
C3—H3	0.9300	C16—H16	0.9299
C4—C5	1.393 (5)	C17—C18	1.402 (6)
C4—H4	0.9299	C17—H17	0.9300
C5—C6	1.380 (5)	C18—C19	1.382 (6)
C5—H5	0.9301	C18—H18	0.9300
C6—C7	1.399 (5)	C19—C20	1.394 (5)
C6—H6	0.9300	C19—H19	0.9301

C1—N1—C2	104.4 (3)	C10—C9—H9	120.0
C1—N2—C7	105.2 (3)	C11—C10—C9	119.5 (3)
C1—N2—C8	127.0 (3)	C11—C10—H10	120.3
C7—N2—C8	127.8 (3)	C9—C10—H10	120.2
C14—N3—C15	106.0 (3)	C12—C11—C10	120.2 (3)
C14—N3—C11	125.8 (3)	C12—C11—N3	119.3 (3)
C15—N3—C11	128.2 (3)	C10—C11—N3	120.5 (3)
C14—N4—C20	103.8 (3)	C11—C12—C13	120.4 (3)
N1—C1—N2	115.0 (3)	C11—C12—H12	119.8
N1—C1—H1	122.5	C13—C12—H12	119.8
N2—C1—H1	122.5	C8—C13—C12	119.4 (3)
C3—C2—N1	130.0 (3)	C8—C13—H13	120.3
C3—C2—C7	120.4 (3)	C12—C13—H13	120.3
N1—C2—C7	109.6 (3)	N4—C14—N3	114.6 (4)
C4—C3—C2	118.0 (3)	N4—C14—H14	122.7
C4—C3—H3	121.0	N3—C14—H14	122.7
C2—C3—H3	120.9	C16—C15—N3	132.8 (3)
C3—C4—C5	121.3 (3)	C16—C15—C20	122.2 (4)
C3—C4—H4	119.3	N3—C15—C20	104.9 (3)
C5—C4—H4	119.4	C17—C16—C15	117.2 (4)
C6—C5—C4	122.3 (4)	C17—C16—H16	121.4
C6—C5—H5	118.9	C15—C16—H16	121.4
C4—C5—H5	118.9	C16—C17—C18	121.5 (5)
C5—C6—C7	116.2 (3)	C16—C17—H17	119.2
C5—C6—H6	121.9	C18—C17—H17	119.3
C7—C6—H6	121.9	C19—C18—C17	121.2 (4)
N2—C7—C6	132.4 (3)	C19—C18—H18	119.4
N2—C7—C2	105.9 (3)	C17—C18—H18	119.4
C6—C7—C2	121.7 (3)	C18—C19—C20	117.7 (4)
C13—C8—C9	120.6 (3)	C18—C19—H19	121.2
C13—C8—N2	119.9 (3)	C20—C19—H19	121.1
C9—C8—N2	119.5 (3)	C19—C20—N4	129.2 (3)
C8—C9—C10	119.8 (3)	C19—C20—C15	120.2 (4)
C8—C9—H9	120.1	N4—C20—C15	110.6 (3)

C2—N1—C1—N2	−0.1 (4)	C14—N3—C11—C12	46.4 (5)
C7—N2—C1—N1	−0.1 (5)	C15—N3—C11—C12	−133.0 (4)
C8—N2—C1—N1	177.2 (4)	C14—N3—C11—C10	−132.3 (4)
C1—N1—C2—C3	179.9 (4)	C15—N3—C11—C10	48.3 (5)
C1—N1—C2—C7	0.2 (4)	C10—C11—C12—C13	1.1 (6)
N1—C2—C3—C4	−178.1 (4)	N3—C11—C12—C13	−177.6 (4)
C7—C2—C3—C4	1.5 (5)	C9—C8—C13—C12	0.9 (6)
C2—C3—C4—C5	0.2 (6)	N2—C8—C13—C12	179.9 (3)
C3—C4—C5—C6	−1.4 (6)	C11—C12—C13—C8	−1.8 (6)
C4—C5—C6—C7	0.8 (6)	C20—N4—C14—N3	0.6 (4)
C1—N2—C7—C6	−177.3 (4)	C15—N3—C14—N4	−0.5 (4)
C8—N2—C7—C6	5.4 (7)	C11—N3—C14—N4	−179.9 (3)
C1—N2—C7—C2	0.2 (4)	C14—N3—C15—C16	−178.0 (4)
C8—N2—C7—C2	−177.1 (3)	C11—N3—C15—C16	1.4 (6)
C5—C6—C7—N2	178.1 (4)	C14—N3—C15—C20	0.1 (4)
C5—C6—C7—C2	1.0 (6)	C11—N3—C15—C20	179.6 (3)
C3—C2—C7—N2	180.0 (3)	N3—C15—C16—C17	177.6 (4)
N1—C2—C7—N2	−0.3 (4)	C20—C15—C16—C17	−0.3 (6)
C3—C2—C7—C6	−2.2 (6)	C15—C16—C17—C18	0.6 (7)
N1—C2—C7—C6	177.6 (4)	C16—C17—C18—C19	−1.0 (7)
C1—N2—C8—C13	−131.9 (4)	C17—C18—C19—C20	1.0 (6)
C7—N2—C8—C13	44.8 (5)	C18—C19—C20—N4	−178.6 (4)
C1—N2—C8—C9	47.1 (5)	C18—C19—C20—C15	−0.6 (5)
C7—N2—C8—C9	−136.2 (4)	C14—N4—C20—C19	177.6 (4)
C13—C8—C9—C10	0.7 (6)	C14—N4—C20—C15	−0.5 (4)
N2—C8—C9—C10	−178.3 (3)	C16—C15—C20—C19	0.3 (5)
C8—C9—C10—C11	−1.4 (6)	N3—C15—C20—C19	−178.1 (3)
C9—C10—C11—C12	0.5 (5)	C16—C15—C20—N4	178.6 (4)
C9—C10—C11—N3	179.2 (3)	N3—C15—C20—N4	0.3 (4)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C1—H1···N4ⁱ	0.93	2.50	3.359 (5)	153
C6—H6···N4ⁱⁱ	0.93	2.56	3.447 (5)	159

Symmetry codes: (i) x−1, y, z; (ii) −x+2, −y+1, z−1/2.

Experimental details

Crystal data
Chemical formula	C₂₀H₁₄N₄
M_r	310.35
Crystal system, space group	Orthorhombic, Pna2₁
Temperature (K)	293
a, b, c (Å)	9.5458 (19), 20.499 (4), 7.9283 (16)
V (Å³)	1551.4 (5)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.08
Crystal size (mm)	0.25 × 0.22 × 0.18

Data collection
Diffractometer	Rigaku Mercury CCD diffractometer
Absorption correction	Multi-scan (CrystalClear; Rigaku/MSC, 2005)
T_min, T_max	0.980, 0.985
No. of measured, independent and observed [I > 2σ(I)] reflections	12744, 1479, 1298
R_int	0.075
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.051, 0.104, 1.17
No. of reflections	1479
No. of parameters	231
No. of restraints	1
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.14, −0.16

Computer programs: CrystalClear (Rigaku/MSC, 2005), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C1—H1···N4ⁱ	0.93	2.50	3.359 (5)	153
C6—H6···N4ⁱⁱ	0.93	2.56	3.447 (5)	159

Symmetry codes: (i) x−1, y, z; (ii) −x+2, −y+1, z−1/2.

References

Li, Z. X., Xu, Y., Zuo, Y., Li, L., Pan, Q., Hu, T. L. & Bu, X. H. (2009). Cryst. Growth Des. 9, 3904–3909. Web of Science CSD CrossRef CAS Google Scholar
Rigaku/MSC (2005). CrystalClear. Rigaku/MSC Inc., The Woodlands, Texas, USA. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Vijayan, N., Bhagavannarayana, G., Balamurugan, N., Babu, R. R., Maurya, K. K., Gopalakrishnan, R. & Ramasamy, P. (2006). J. Cryst. Growth, 293, 318–323. Web of Science CrossRef CAS Google Scholar

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ISSN: 2056-9890

Volume 67| Part 9| September 2011| Page o2286

doi:10.1107/S1600536811031278

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