N,N′-Bis(2,3-dimeth­oxy­benzyl­idene)ethane-1,2-diamine

Xue, H.; Li, W.; Han, H.

doi:10.1107/S1600536811033423

organic compounds

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ISSN: 2056-9890

Volume 67| Part 9| September 2011| Page o2431

doi:10.1107/S1600536811033423

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N,N′-Bis(2,3-dimethoxybenzylidene)ethane-1,2-diamine

Hua Xue,^a Wenjuan Li ^b and Hongfei Han ^b ^*

^aInstitute of Applied Chemistry, Taiyuan Normal University, Taiyuan 030031, People's Republic of China, and ^bDepartment of Chemistry, Taiyuan Normal University, Taiyuan 030031, People's Republic of China
^*Correspondence e-mail: hhf_2222@yahoo.com.cn

(Received 15 August 2011; accepted 17 August 2011; online 27 August 2011)

The title compound, C₂₀H₂₄N₂O₄, crystallizes with two half (centrosymmetric) molecules in the asymmetric unit. There are only minor differences between the geometric parameters between these two molecules. The two aromatic rings in both molecules are mutually coplanar.

Related literature

For general background to the properties of Schiff bases, see: Layer (1963 ); Chen et al. (2008 ); May et al. (2004 ). For related structures, see: Harada et al. (2004 ); Tariq et al. (2010 ).

Experimental

Crystal data

C₂₀H₂₄N₂O₄
M_r = 356.41
Triclinic, $[P \overline 1]$
a = 5.0491 (5) Å
b = 13.5803 (15) Å
c = 13.5803 (15) Å
α = 89.866 (2)°
β = 88.863 (1)°
γ = 88.863 (1)°
V = 930.81 (17) Å³
Z = 2
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 298 K
0.47 × 0.41 × 0.40 mm

Data collection

Bruker SMART CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ) T_min = 0.959, T_max = 0.965
4767 measured reflections
3207 independent reflections
1811 reflections with I > 2σ(I)
R_int = 0.034

Refinement

R[F² > 2σ(F²)] = 0.062
wR(F²) = 0.184
S = 1.04
3207 reflections
239 parameters
H-atom parameters constrained
Δρ_max = 0.23 e Å⁻³
Δρ_min = −0.26 e Å⁻³

Data collection: SMART (Bruker, 2007 ); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT; 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.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811033423/bt5615sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536811033423/bt5615Isup2.hkl

Supporting information file. DOI: 10.1107/S1600536811033423/bt5615Isup3.cml

checkCIF report

Comment top

Schiff bases containing the C═N bond have been receiving considerable attention for many years, primarily due to their importance as ligands in metal complexes with special biological (May et al., 2004), and catalytic properties (Chen et al., 2008).

As a part of our studies on synthesis and structural peculiarities of Schiff bases derived from 1,2-diaminoethane and 2,3-dimethoxybenzaldehyde, we determined the structure of the title compound (Fig. 1). The molecule includes two C═N bonds, which are coplanar. The distance between the C atom and the N atom in the C═N bond is 1.254 (4) Å. The two benzene rings in the structure are parallel each other.

Related literature top

For general background to the properties of Schiff bases, see: Layer (1963); Chen et al. (2008); May et al. (2004). For related structures, see: Harada et al. (2004); Tariq et al. (2010).

Experimental top

1,2-Diaminoethane (0.180 g, 3 mmol) was added dropwise with stirring at 0°C to a solution of 2,3-dimethoxybenzaldehyde (0.997 g, 6 mmol) in ethanol. The mixture was warmed to room temperature and stirred for 2 h. The reaction mixture was filtered and the filter cake was recrystallized from ethanol (yield 80%). Crystals of the title compound suitable for X-ray diffraction were obtained by slow evaporation of a tetrahydrofuran solution.

Computing details top

Data collection: SMART (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 20077); 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 the title compound, showing the atom–numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.

N,N'-Bis(2,3-dimethoxybenzylidene)ethane-1,2-diamine top

Crystal data top

C₂₀H₂₄N₂O₄	Z = 2
M_r = 356.41	F(000) = 380
Triclinic, P1	D_x = 1.272 Mg m⁻³
a = 5.0491 (5) Å	Mo Kα radiation, λ = 0.71073 Å
b = 13.5803 (15) Å	Cell parameters from 1477 reflections
c = 13.5803 (15) Å	θ = 3.0–25.3°
α = 89.866 (2)°	µ = 0.09 mm⁻¹
β = 88.863 (1)°	T = 298 K
γ = 88.863 (1)°	Block, colorless
V = 930.81 (17) Å³	0.47 × 0.41 × 0.40 mm

Data collection top

Bruker SMART CCD area-detector diffractometer	3207 independent reflections
Radiation source: fine-focus sealed tube	1811 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.034
ϕ and ω scans	θ_max = 25.0°, θ_min = 3.0°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −5→6
T_min = 0.959, T_max = 0.965	k = −11→16
4767 measured reflections	l = −16→15

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)] = 0.062	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.184	H-atom parameters constrained
S = 1.04	w = 1/[σ²(F_o²) + (0.087P)² + 0.1177P] where P = (F_o² + 2F_c²)/3
3207 reflections	(Δ/σ)_max < 0.001
239 parameters	Δρ_max = 0.23 e Å⁻³
0 restraints	Δρ_min = −0.26 e Å⁻³

Crystal data top

C₂₀H₂₄N₂O₄	γ = 88.863 (1)°
M_r = 356.41	V = 930.81 (17) Å³
Triclinic, P1	Z = 2
a = 5.0491 (5) Å	Mo Kα radiation
b = 13.5803 (15) Å	µ = 0.09 mm⁻¹
c = 13.5803 (15) Å	T = 298 K
α = 89.866 (2)°	0.47 × 0.41 × 0.40 mm
β = 88.863 (1)°

Data collection top

Bruker SMART CCD area-detector diffractometer	3207 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	1811 reflections with I > 2σ(I)
T_min = 0.959, T_max = 0.965	R_int = 0.034
4767 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.062	0 restraints
wR(F²) = 0.184	H-atom parameters constrained
S = 1.04	Δρ_max = 0.23 e Å⁻³
3207 reflections	Δρ_min = −0.26 e Å⁻³
239 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	0.8830 (5)	0.89133 (19)	0.93288 (19)	0.0473 (7)
N2	−0.3832 (5)	0.39082 (19)	0.56712 (18)	0.0465 (7)
O1	0.3838 (4)	0.91237 (15)	0.70797 (15)	0.0485 (6)
O2	0.0726 (4)	0.76450 (16)	0.65165 (16)	0.0531 (6)
O3	0.1160 (4)	0.41215 (15)	0.79204 (15)	0.0485 (6)
O4	0.4260 (4)	0.26460 (16)	0.84843 (16)	0.0530 (6)
C1	0.7533 (6)	0.8916 (2)	0.8551 (2)	0.0412 (8)
H1	0.7668	0.9451	0.8126	0.049*
C2	0.5804 (6)	0.8102 (2)	0.8286 (2)	0.0382 (7)
C3	0.4037 (6)	0.8220 (2)	0.7529 (2)	0.0376 (7)
C4	0.2413 (6)	0.7449 (2)	0.7263 (2)	0.0403 (8)
C5	0.2564 (7)	0.6562 (2)	0.7739 (2)	0.0476 (9)
H5	0.1496	0.6046	0.7557	0.057*
C6	0.4331 (7)	0.6448 (2)	0.8495 (2)	0.0536 (9)
H6	0.4449	0.5848	0.8825	0.064*
C7	0.5912 (7)	0.7204 (2)	0.8764 (2)	0.0486 (9)
H7	0.7080	0.7111	0.9279	0.058*
C8	0.5069 (9)	0.9172 (3)	0.6126 (3)	0.0718 (12)
H8A	0.6926	0.9019	0.6176	0.108*
H8B	0.4839	0.9824	0.5862	0.108*
H8C	0.4270	0.8706	0.5698	0.108*
C9	−0.0886 (7)	0.6865 (3)	0.6191 (3)	0.0581 (10)
H9A	0.0225	0.6333	0.5948	0.087*
H9B	−0.2003	0.7100	0.5673	0.087*
H9C	−0.1965	0.6636	0.6731	0.087*
C10	1.0447 (6)	0.9765 (2)	0.9517 (2)	0.0475 (8)
H10A	1.0266	1.0238	0.8985	0.057*
H10B	1.2296	0.9563	0.9550	0.057*
C11	−0.2531 (6)	0.3919 (2)	0.6447 (2)	0.0401 (8)
H11	−0.2679	0.4464	0.6860	0.048*
C12	−0.0791 (6)	0.3099 (2)	0.6716 (2)	0.0371 (7)
C13	0.0954 (6)	0.3223 (2)	0.7471 (2)	0.0366 (7)
C14	0.2596 (6)	0.2440 (2)	0.7735 (2)	0.0410 (8)
C15	0.2442 (7)	0.1563 (2)	0.7261 (2)	0.0476 (8)
H15	0.3533	0.1038	0.7447	0.057*
C16	0.0680 (7)	0.1443 (2)	0.6506 (2)	0.0542 (9)
H16	0.0591	0.0840	0.6187	0.065*
C17	−0.0920 (7)	0.2208 (2)	0.6233 (2)	0.0478 (8)
H17	−0.2097	0.2131	0.5722	0.057*
C18	−0.0072 (9)	0.4175 (3)	0.8874 (3)	0.0732 (12)
H18A	−0.1927	0.4047	0.8823	0.110*
H18B	0.0152	0.4820	0.9143	0.110*
H18C	0.0731	0.3693	0.9298	0.110*
C19	0.5896 (7)	0.1861 (3)	0.8810 (3)	0.0576 (10)
H19A	0.4812	0.1339	0.9058	0.086*
H19B	0.7008	0.2088	0.9324	0.086*
H19C	0.6979	0.1621	0.8270	0.086*
C20	−0.5456 (6)	0.4766 (2)	0.5481 (2)	0.0466 (8)
H20A	−0.5313	0.5233	0.6015	0.056*
H20B	−0.7296	0.4581	0.5437	0.056*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
N1	0.0444 (17)	0.0526 (17)	0.0455 (16)	−0.0109 (13)	−0.0038 (13)	−0.0035 (12)
N2	0.0435 (17)	0.0508 (17)	0.0450 (16)	0.0084 (13)	−0.0041 (13)	0.0012 (12)
O1	0.0537 (15)	0.0412 (13)	0.0506 (14)	0.0013 (10)	−0.0041 (11)	0.0001 (10)
O2	0.0421 (14)	0.0577 (15)	0.0600 (14)	−0.0042 (11)	−0.0126 (11)	−0.0077 (11)
O3	0.0510 (14)	0.0437 (13)	0.0511 (14)	−0.0042 (11)	−0.0052 (11)	0.0006 (10)
O4	0.0422 (14)	0.0563 (15)	0.0609 (14)	0.0030 (11)	−0.0122 (11)	0.0088 (11)
C1	0.0410 (19)	0.0426 (18)	0.0399 (18)	−0.0035 (15)	0.0031 (15)	−0.0032 (14)
C2	0.0334 (18)	0.0415 (18)	0.0396 (17)	−0.0047 (14)	0.0039 (14)	−0.0055 (14)
C3	0.0364 (18)	0.0353 (18)	0.0410 (17)	−0.0004 (14)	0.0047 (14)	−0.0043 (13)
C4	0.0312 (18)	0.0459 (19)	0.0435 (18)	0.0001 (15)	0.0026 (15)	−0.0100 (14)
C5	0.039 (2)	0.044 (2)	0.060 (2)	−0.0077 (15)	0.0030 (17)	−0.0073 (16)
C6	0.057 (2)	0.046 (2)	0.059 (2)	−0.0063 (17)	−0.0039 (18)	0.0084 (16)
C7	0.049 (2)	0.052 (2)	0.0447 (19)	−0.0042 (17)	−0.0054 (16)	0.0007 (15)
C8	0.092 (3)	0.066 (3)	0.058 (2)	0.000 (2)	0.003 (2)	0.0093 (19)
C9	0.037 (2)	0.070 (2)	0.068 (2)	−0.0042 (18)	−0.0082 (18)	−0.0223 (19)
C10	0.0351 (19)	0.058 (2)	0.0502 (19)	−0.0087 (16)	−0.0039 (15)	0.0004 (15)
C11	0.0389 (19)	0.0429 (18)	0.0385 (18)	0.0000 (15)	0.0017 (15)	0.0005 (13)
C12	0.0324 (17)	0.0377 (18)	0.0410 (17)	0.0000 (14)	0.0023 (14)	0.0037 (13)
C13	0.0334 (18)	0.0347 (17)	0.0415 (17)	−0.0036 (14)	0.0025 (14)	0.0021 (13)
C14	0.0335 (18)	0.0439 (19)	0.0452 (19)	−0.0010 (15)	0.0033 (15)	0.0102 (15)
C15	0.042 (2)	0.044 (2)	0.056 (2)	0.0040 (15)	0.0024 (17)	0.0040 (16)
C16	0.059 (2)	0.041 (2)	0.062 (2)	0.0030 (17)	0.0016 (19)	−0.0088 (16)
C17	0.046 (2)	0.051 (2)	0.0466 (19)	0.0015 (17)	−0.0048 (16)	−0.0036 (15)
C18	0.095 (3)	0.065 (3)	0.059 (2)	0.002 (2)	0.004 (2)	−0.0108 (19)
C19	0.040 (2)	0.063 (2)	0.071 (2)	0.0084 (17)	−0.0075 (18)	0.0232 (18)
C20	0.0361 (19)	0.056 (2)	0.0472 (18)	0.0086 (16)	−0.0053 (15)	−0.0002 (15)

Geometric parameters (Å, º) top

N1—C1	1.254 (4)	C9—H9A	0.9600
N1—C10	1.455 (4)	C9—H9B	0.9600
N2—C11	1.253 (4)	C9—H9C	0.9600
N2—C20	1.437 (4)	C10—C10ⁱ	1.517 (6)
O1—C3	1.372 (3)	C10—H10A	0.9700
O1—C8	1.428 (4)	C10—H10B	0.9700
O2—C4	1.360 (4)	C11—C12	1.456 (4)
O2—C9	1.425 (4)	C11—H11	0.9300
O3—C13	1.373 (3)	C12—C13	1.378 (4)
O3—C18	1.427 (4)	C12—C17	1.381 (4)
O4—C14	1.366 (4)	C13—C14	1.386 (4)
O4—C19	1.411 (4)	C14—C15	1.359 (4)
C1—C2	1.472 (4)	C15—C16	1.382 (5)
C1—H1	0.9300	C15—H15	0.9300
C2—C7	1.381 (4)	C16—C17	1.359 (4)
C2—C3	1.381 (4)	C16—H16	0.9300
C3—C4	1.395 (4)	C17—H17	0.9300
C4—C5	1.367 (4)	C18—H18A	0.9600
C5—C6	1.379 (4)	C18—H18B	0.9600
C5—H5	0.9300	C18—H18C	0.9600
C6—C7	1.368 (4)	C19—H19A	0.9600
C6—H6	0.9300	C19—H19B	0.9600
C7—H7	0.9300	C19—H19C	0.9600
C8—H8A	0.9600	C20—C20ⁱⁱ	1.518 (6)
C8—H8B	0.9600	C20—H20A	0.9700
C8—H8C	0.9600	C20—H20B	0.9700

C1—N1—C10	117.4 (3)	N1—C10—H10B	109.8
C11—N2—C20	116.3 (3)	C10ⁱ—C10—H10B	109.8
C3—O1—C8	114.6 (2)	H10A—C10—H10B	108.3
C4—O2—C9	117.7 (3)	N2—C11—C12	121.4 (3)
C13—O3—C18	114.0 (2)	N2—C11—H11	119.3
C14—O4—C19	116.3 (3)	C12—C11—H11	119.3
N1—C1—C2	122.3 (3)	C13—C12—C17	120.7 (3)
N1—C1—H1	118.8	C13—C12—C11	118.8 (3)
C2—C1—H1	118.8	C17—C12—C11	120.5 (3)
C7—C2—C3	118.1 (3)	O3—C13—C12	120.5 (3)
C7—C2—C1	121.9 (3)	O3—C13—C14	120.4 (3)
C3—C2—C1	119.9 (3)	C12—C13—C14	118.9 (3)
O1—C3—C2	118.4 (3)	C15—C14—O4	125.9 (3)
O1—C3—C4	121.1 (3)	C15—C14—C13	120.0 (3)
C2—C3—C4	120.4 (3)	O4—C14—C13	114.1 (3)
O2—C4—C5	123.6 (3)	C14—C15—C16	120.8 (3)
O2—C4—C3	115.8 (3)	C14—C15—H15	119.6
C5—C4—C3	120.6 (3)	C16—C15—H15	119.6
C4—C5—C6	118.7 (3)	C17—C16—C15	119.8 (3)
C4—C5—H5	120.6	C17—C16—H16	120.1
C6—C5—H5	120.6	C15—C16—H16	120.1
C7—C6—C5	120.9 (3)	C16—C17—C12	119.8 (3)
C7—C6—H6	119.5	C16—C17—H17	120.1
C5—C6—H6	119.5	C12—C17—H17	120.1
C6—C7—C2	121.2 (3)	O3—C18—H18A	109.5
C6—C7—H7	119.4	O3—C18—H18B	109.5
C2—C7—H7	119.4	H18A—C18—H18B	109.5
O1—C8—H8A	109.5	O3—C18—H18C	109.5
O1—C8—H8B	109.5	H18A—C18—H18C	109.5
H8A—C8—H8B	109.5	H18B—C18—H18C	109.5
O1—C8—H8C	109.5	O4—C19—H19A	109.5
H8A—C8—H8C	109.5	O4—C19—H19B	109.5
H8B—C8—H8C	109.5	H19A—C19—H19B	109.5
O2—C9—H9A	109.5	O4—C19—H19C	109.5
O2—C9—H9B	109.5	H19A—C19—H19C	109.5
H9A—C9—H9B	109.5	H19B—C19—H19C	109.5
O2—C9—H9C	109.5	N2—C20—C20ⁱⁱ	109.2 (3)
H9A—C9—H9C	109.5	N2—C20—H20A	109.8
H9B—C9—H9C	109.5	C20ⁱⁱ—C20—H20A	109.8
N1—C10—C10ⁱ	109.3 (3)	N2—C20—H20B	109.8
N1—C10—H10A	109.8	C20ⁱⁱ—C20—H20B	109.8
C10ⁱ—C10—H10A	109.8	H20A—C20—H20B	108.3

C10—N1—C1—C2	−179.3 (3)	C20—N2—C11—C12	−179.3 (3)
N1—C1—C2—C7	−13.6 (5)	N2—C11—C12—C13	168.0 (3)
N1—C1—C2—C3	167.5 (3)	N2—C11—C12—C17	−13.0 (5)
C8—O1—C3—C2	105.0 (3)	C18—O3—C13—C12	104.8 (3)
C8—O1—C3—C4	−78.0 (4)	C18—O3—C13—C14	−78.6 (4)
C7—C2—C3—O1	177.2 (3)	C17—C12—C13—O3	177.1 (3)
C1—C2—C3—O1	−3.8 (4)	C11—C12—C13—O3	−4.0 (4)
C7—C2—C3—C4	0.2 (4)	C17—C12—C13—C14	0.5 (4)
C1—C2—C3—C4	179.2 (3)	C11—C12—C13—C14	179.4 (3)
C9—O2—C4—C5	−2.7 (4)	C19—O4—C14—C15	−2.2 (4)
C9—O2—C4—C3	177.2 (3)	C19—O4—C14—C13	177.4 (3)
O1—C3—C4—O2	2.4 (4)	O3—C13—C14—C15	−177.6 (3)
C2—C3—C4—O2	179.3 (2)	C12—C13—C14—C15	−1.0 (4)
O1—C3—C4—C5	−177.7 (3)	O3—C13—C14—O4	2.8 (4)
C2—C3—C4—C5	−0.8 (4)	C12—C13—C14—O4	179.4 (2)
O2—C4—C5—C6	−179.3 (3)	O4—C14—C15—C16	−179.7 (3)
C3—C4—C5—C6	0.8 (4)	C13—C14—C15—C16	0.8 (5)
C4—C5—C6—C7	−0.2 (5)	C14—C15—C16—C17	0.0 (5)
C5—C6—C7—C2	−0.4 (5)	C15—C16—C17—C12	−0.5 (5)
C3—C2—C7—C6	0.4 (5)	C13—C12—C17—C16	0.3 (5)
C1—C2—C7—C6	−178.6 (3)	C11—C12—C17—C16	−178.6 (3)
C1—N1—C10—C10ⁱ	120.9 (4)	C11—N2—C20—C20ⁱⁱ	119.1 (4)

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

Experimental details

Crystal data
Chemical formula	C₂₀H₂₄N₂O₄
M_r	356.41
Crystal system, space group	Triclinic, P1
Temperature (K)	298
a, b, c (Å)	5.0491 (5), 13.5803 (15), 13.5803 (15)
α, β, γ (°)	89.866 (2), 88.863 (1), 88.863 (1)
V (Å³)	930.81 (17)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.09
Crystal size (mm)	0.47 × 0.41 × 0.40

Data collection
Diffractometer	Bruker SMART CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.959, 0.965
No. of measured, independent and observed [I > 2σ(I)] reflections	4767, 3207, 1811
R_int	0.034
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.062, 0.184, 1.04
No. of reflections	3207
No. of parameters	239
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.23, −0.26

Computer programs: SMART (Bruker, 2007), SAINT (Bruker, 2007), SAINT (Bruker, 20077), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Acknowledgements

This work was carried out under the sponsorship of the project of ShanXi scientific technology (20110321044).

References

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