2,4-Dimethyl-6-nitro­aniline

Chen, H.-K.

doi:10.1107/S1600536812014547

organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 68| Part 5| May 2012| Page o1392

doi:10.1107/S1600536812014547

Open

access

2,4-Dimethyl-6-nitroaniline

Hu-Kui Chen ^a ^*

^aBaoji University of Arts and Sciences, Department of Chemistry, Baoji 721013, Shaanxi, People's Republic of China
^*Correspondence e-mail: chenhukui@163.com

(Received 19 March 2012; accepted 3 April 2012; online 13 April 2012)

The asymmetric unit of the title compound, C₈H₁₀N₂O₂, contains two independent molecules, which are linked by weak N—H⋯O hydrogen-bonding interactions between the amino and nitro groups. The independent molecules are both approximately planar with r.s.d. deviations of 0.0216 and 0.0161 Å.

Related literature

For applications of the title compound and background to the synthesis, see: Qian (2005 ); Qi et al. (2009 ); Liang (2000 ); Hu et al. (2010 ).

Experimental

Crystal data

C₈H₁₀N₂O₂
M_r = 166.18
Monoclinic, P 2₁ /c
a = 6.997 (2) Å
b = 14.919 (4) Å
c = 15.907 (5) Å
β = 101.176 (4)°
V = 1629.1 (8) Å³
Z = 8
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 163 K
0.37 × 0.35 × 0.24 mm

Data collection

Rigaku AFC10/Saturn724+ diffractometer
10540 measured reflections
4325 independent reflections
3104 reflections with I > 2σ(I)
R_int = 0.027

Refinement

R[F² > 2σ(F²)] = 0.049
wR(F²) = 0.134
S = 1.00
4325 reflections
237 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.32 e Å⁻³
Δρ_min = −0.21 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1A⋯O3	0.91 (2)	2.27 (2)	3.166 (2)	167.9 (18)
N3—H3B⋯O4	0.93 (2)	1.92 (2)	2.631 (2)	131.3 (17)
N3—H3A⋯O2ⁱ	0.89 (2)	2.30 (2)	3.1667 (19)	165.8 (17)
N1—H1B⋯O2	0.86 (2)	1.972 (18)	2.6233 (19)	131.4 (16)
Symmetry code: (i) $[-x+1, y-{\script{1\over 2}}, -z+{\script{3\over 2}}]$ .

Data collection: CrystalClear (Rigaku/MSC, 2008); 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: SHELXL97.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536812014547/zj2069sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536812014547/zj2069Isup2.hkl

Supporting information file. DOI: 10.1107/S1600536812014547/zj2069Isup3.cml

checkCIF report

Comment top

The tittle compound,2,4-dimethyl-6-nitroaniline, is a very important aromatic organic intermediate, which can be utilized to synthesize dyes and pigment. It is practical significant to research and develop 2,4-dimethyl-6-nitroaniline because of difficult synthesis process, higher costs and bad yield. To improve the reaction condition and enlarge the needs of it, we report here the crystal structure of the title compound 2,4-dimethyl-6-nitroaniline,(I).

The molecular structure of (I) is shown in Fig.1. The asymmetric unit contains two title molecules of 2,4-dimethyl-6-nitroaniline. The non-hydrogen atoms of these molecules molecule are situated in a fair plane with r.m.s.deviation of 0.0216 Å and 0.0161 Å. The bond lengths and angles are within normal ranges in both molecules. In the crystal structure, the two molecules are not parallel but have a dihedral angle of 2.19 (0.02)°. The intermolecular N—H···O hydrogen bonds (Table 1) link the molecules (Fig. 2), in which they may be effective in the stabilization of the structure.

Related literature top

For applications of the title compound and background to the synthesis, see: Qian (2005); Qi et al. (2009); Liang (2000); Hu et al. (2010).

Experimental top

A solution of 2,4-dimethylaniline(24.2 g, 0.2 mol), acetic acid(23 ml) and acetic anhydride (19 ml) was refluxed for 1 h and cooled to 35°C. Then, the mixed acid of concentrated sulfuric acid(35 ml) and concentrated nitric acid (17 ml) was slowly dropped into it after concentrated sulfuric acids(40 ml) was added. The mixture was reacted for 1 h and cooled to the room tempreture, and added to the cooled water.The resultant white solid 2,4-dimethylacetanilide was filtered and washed with cooled water. 2,4-dimethylacetanilide was then was added to the solution of 70% sulfuric acids (80 ml) and refluxed for 1 h, and slowly added to the cooled water.Orange-red precipitate began to appear. The precipitate was filtered and washed with water until the pH value of the filtrate is 7. The solid product was collected after dried at 80 °C(yield 82.5%, mp.70–72 °C).The crystals of 2,4-dimethyl-6-nitroaniline suitable for X-ray analysis were obtained by dissolving (I) (0.1 g) in methanol (20 ml) and evaporating the solvent slowly at room temperature for about 10 d.

Computing details top

Data collection: CrystalClear (Rigaku/MSC, 2008); cell refinement: CrystalClear (Rigaku/MSC, 2008); data reduction: CrystalClear (Rigaku/MSC, 2008); 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: SHELXL97 (Sheldrick, 2008).

Figures top

	Fig. 1. The molecular structure of (I), with the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.
	Fig. 2. Part of the packing of the title compound, viewed down the b axis. Dashed lines indicate hydrogen bonds.

2,4-Dimethyl-6-nitroaniline top

Crystal data top

C₈H₁₀N₂O₂	F(000) = 704
M_r = 166.18	D_x = 1.355 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 4298 reflections
a = 6.997 (2) Å	θ = 2.6–29.1°
b = 14.919 (4) Å	µ = 0.10 mm⁻¹
c = 15.907 (5) Å	T = 163 K
β = 101.176 (4)°	Block, red
V = 1629.1 (8) Å³	0.37 × 0.35 × 0.24 mm
Z = 8

Data collection top

Rigaku AFC10/Saturn724+ diffractometer	3104 reflections with I > 2σ(I)
Radiation source: Rotating Anode	R_int = 0.027
Graphite monochromator	θ_max = 29.1°, θ_min = 2.6°
Detector resolution: 28.5714 pixels mm^-1	h = −9→9
phi and ω scans	k = −20→13
10540 measured reflections	l = −19→21
4325 independent 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)] = 0.049	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.134	H atoms treated by a mixture of independent and constrained refinement
S = 1.00	w = 1/[σ²(F_o²) + (0.0669P)² + 0.169P] where P = (F_o² + 2F_c²)/3
4325 reflections	(Δ/σ)_max < 0.001
237 parameters	Δρ_max = 0.32 e Å⁻³
0 restraints	Δρ_min = −0.21 e Å⁻³

Crystal data top

C₈H₁₀N₂O₂	V = 1629.1 (8) Å³
M_r = 166.18	Z = 8
Monoclinic, P2₁/c	Mo Kα radiation
a = 6.997 (2) Å	µ = 0.10 mm⁻¹
b = 14.919 (4) Å	T = 163 K
c = 15.907 (5) Å	0.37 × 0.35 × 0.24 mm
β = 101.176 (4)°

Data collection top

Rigaku AFC10/Saturn724+ diffractometer	3104 reflections with I > 2σ(I)
10540 measured reflections	R_int = 0.027
4325 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.049	0 restraints
wR(F²) = 0.134	H atoms treated by a mixture of independent and constrained refinement
S = 1.00	Δρ_max = 0.32 e Å⁻³
4325 reflections	Δρ_min = −0.21 e Å⁻³
237 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
O1	0.45092 (17)	0.90397 (8)	0.58620 (8)	0.0475 (3)
O2	0.44448 (18)	0.76422 (8)	0.61993 (7)	0.0461 (3)
O3	0.1904 (2)	0.44185 (8)	0.46076 (8)	0.0515 (3)
O4	0.28094 (19)	0.46393 (7)	0.59626 (8)	0.0488 (3)
N1	0.32759 (19)	0.64184 (9)	0.50283 (9)	0.0337 (3)
N2	0.42024 (17)	0.82485 (8)	0.56491 (8)	0.0331 (3)
N3	0.29546 (19)	0.33074 (9)	0.70576 (9)	0.0349 (3)
N4	0.22429 (19)	0.41310 (8)	0.53454 (9)	0.0351 (3)
C1	0.31439 (18)	0.71292 (9)	0.44965 (9)	0.0253 (3)
C2	0.25692 (19)	0.69862 (9)	0.35968 (9)	0.0267 (3)
C3	0.2419 (2)	0.77019 (9)	0.30489 (10)	0.0293 (3)
H3	0.2037	0.7591	0.2452	0.035*
C4	0.28002 (19)	0.85946 (9)	0.33221 (10)	0.0294 (3)
C5	0.33876 (19)	0.87389 (9)	0.41793 (10)	0.0278 (3)
H5	0.3681	0.9331	0.4384	0.033*
C6	0.35645 (18)	0.80271 (9)	0.47637 (9)	0.0251 (3)
C7	0.2177 (2)	0.60435 (10)	0.32704 (11)	0.0385 (4)
H7A	0.1968	0.6043	0.2643	0.046*
H7B	0.1013	0.5812	0.3453	0.046*
H7C	0.3296	0.5662	0.3502	0.046*
C8	0.2570 (2)	0.93525 (10)	0.26839 (11)	0.0409 (4)
H8A	0.1247	0.9595	0.2610	0.049*
H8B	0.2800	0.9129	0.2133	0.049*
H8C	0.3514	0.9826	0.2894	0.049*
C9	0.24075 (18)	0.28267 (9)	0.63273 (9)	0.0258 (3)
C10	0.21597 (19)	0.18803 (9)	0.63927 (10)	0.0281 (3)
C11	0.15958 (19)	0.13826 (9)	0.56628 (10)	0.0306 (3)
H11	0.1458	0.0753	0.5721	0.037*
C12	0.12098 (19)	0.17490 (9)	0.48338 (10)	0.0293 (3)
C13	0.14163 (19)	0.26569 (9)	0.47631 (9)	0.0283 (3)
H13	0.1161	0.2930	0.4213	0.034*
C14	0.20012 (19)	0.31878 (9)	0.54949 (9)	0.0262 (3)
C15	0.2515 (2)	0.14538 (10)	0.72614 (11)	0.0394 (4)
H15A	0.2234	0.0811	0.7203	0.047*
H15B	0.1664	0.1730	0.7610	0.047*
H15C	0.3879	0.1541	0.7540	0.047*
C16	0.0600 (2)	0.11639 (11)	0.40631 (11)	0.0405 (4)
H16A	−0.0791	0.1027	0.3993	0.049*
H16B	0.1351	0.0605	0.4140	0.049*
H16C	0.0843	0.1477	0.3552	0.049*
H1A	0.284 (3)	0.5869 (14)	0.4823 (13)	0.056 (6)*
H3B	0.325 (3)	0.3907 (14)	0.6975 (13)	0.066 (6)*
H3A	0.350 (3)	0.3063 (13)	0.7554 (14)	0.057 (6)*
H1B	0.355 (3)	0.6534 (11)	0.5569 (13)	0.043 (5)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0653 (8)	0.0384 (6)	0.0380 (7)	−0.0122 (5)	0.0081 (6)	−0.0142 (5)
O2	0.0680 (8)	0.0467 (7)	0.0214 (6)	−0.0050 (5)	0.0030 (5)	0.0041 (5)
O3	0.0844 (9)	0.0360 (6)	0.0324 (7)	−0.0024 (6)	0.0068 (6)	0.0128 (5)
O4	0.0798 (9)	0.0277 (5)	0.0375 (7)	−0.0049 (5)	0.0080 (6)	−0.0050 (5)
N1	0.0471 (7)	0.0276 (6)	0.0246 (7)	−0.0015 (5)	0.0023 (6)	0.0057 (6)
N2	0.0349 (7)	0.0365 (7)	0.0277 (7)	−0.0036 (5)	0.0054 (5)	−0.0026 (6)
N3	0.0479 (8)	0.0333 (7)	0.0230 (7)	0.0004 (5)	0.0063 (6)	−0.0028 (6)
N4	0.0470 (7)	0.0285 (6)	0.0302 (7)	0.0015 (5)	0.0083 (5)	0.0037 (6)
C1	0.0249 (6)	0.0259 (6)	0.0251 (7)	0.0004 (5)	0.0045 (5)	0.0042 (5)
C2	0.0282 (7)	0.0262 (6)	0.0246 (8)	0.0007 (5)	0.0020 (5)	0.0003 (6)
C3	0.0325 (7)	0.0324 (7)	0.0217 (7)	0.0028 (5)	0.0019 (5)	0.0022 (6)
C4	0.0314 (7)	0.0277 (7)	0.0302 (8)	0.0013 (5)	0.0087 (5)	0.0069 (6)
C5	0.0292 (7)	0.0243 (6)	0.0308 (8)	−0.0013 (5)	0.0077 (5)	0.0005 (6)
C6	0.0260 (6)	0.0279 (7)	0.0217 (7)	−0.0014 (5)	0.0052 (5)	−0.0004 (6)
C7	0.0528 (9)	0.0293 (8)	0.0293 (9)	−0.0007 (6)	−0.0025 (7)	−0.0020 (6)
C8	0.0516 (9)	0.0351 (8)	0.0360 (10)	0.0033 (6)	0.0083 (7)	0.0126 (7)
C9	0.0279 (7)	0.0286 (7)	0.0220 (7)	0.0011 (5)	0.0075 (5)	−0.0008 (6)
C10	0.0295 (7)	0.0295 (7)	0.0264 (8)	0.0010 (5)	0.0081 (5)	0.0044 (6)
C11	0.0321 (7)	0.0256 (7)	0.0348 (9)	−0.0029 (5)	0.0079 (6)	0.0019 (6)
C12	0.0271 (7)	0.0318 (7)	0.0292 (8)	−0.0007 (5)	0.0058 (5)	−0.0038 (6)
C13	0.0295 (7)	0.0333 (7)	0.0226 (7)	0.0016 (5)	0.0062 (5)	0.0013 (6)
C14	0.0303 (7)	0.0235 (6)	0.0256 (7)	0.0013 (5)	0.0075 (5)	0.0012 (6)
C15	0.0476 (9)	0.0382 (8)	0.0325 (9)	0.0002 (6)	0.0082 (7)	0.0106 (7)
C16	0.0447 (9)	0.0397 (8)	0.0354 (10)	−0.0047 (6)	0.0032 (7)	−0.0106 (7)

Geometric parameters (Å, º) top

O1—N2	1.2353 (16)	C7—H7A	0.9800
O2—N2	1.2472 (17)	C7—H7B	0.9800
O3—N4	1.2288 (17)	C7—H7C	0.9800
O4—N4	1.2431 (17)	C8—H8A	0.9800
N1—C1	1.3484 (18)	C8—H8B	0.9800
N1—H1A	0.91 (2)	C8—H8C	0.9800
N1—H1B	0.86 (2)	C9—C14	1.407 (2)
N2—C6	1.4311 (19)	C9—C10	1.4287 (19)
N3—C9	1.3557 (19)	C10—C11	1.370 (2)
N3—H3B	0.93 (2)	C10—C15	1.498 (2)
N3—H3A	0.89 (2)	C11—C12	1.405 (2)
N4—C14	1.4424 (18)	C11—H11	0.9500
C1—C6	1.4189 (18)	C12—C13	1.369 (2)
C1—C2	1.426 (2)	C12—C16	1.498 (2)
C2—C3	1.3693 (19)	C13—C14	1.402 (2)
C2—C7	1.5058 (19)	C13—H13	0.9500
C3—C4	1.410 (2)	C15—H15A	0.9800
C3—H3	0.9500	C15—H15B	0.9800
C4—C5	1.363 (2)	C15—H15C	0.9800
C4—C8	1.507 (2)	C16—H16A	0.9800
C5—C6	1.4009 (19)	C16—H16B	0.9800
C5—H5	0.9500	C16—H16C	0.9800

C1—N1—H1A	120.3 (13)	C4—C8—H8A	109.5
C1—N1—H1B	116.4 (12)	C4—C8—H8B	109.5
H1A—N1—H1B	122.1 (17)	H8A—C8—H8B	109.5
O1—N2—O2	120.51 (13)	C4—C8—H8C	109.5
O1—N2—C6	119.66 (13)	H8A—C8—H8C	109.5
O2—N2—C6	119.83 (12)	H8B—C8—H8C	109.5
C9—N3—H3B	114.8 (13)	N3—C9—C14	125.17 (13)
C9—N3—H3A	123.1 (13)	N3—C9—C10	118.59 (13)
H3B—N3—H3A	116.9 (18)	C14—C9—C10	116.22 (13)
O3—N4—O4	120.95 (13)	C11—C10—C9	119.53 (13)
O3—N4—C14	119.40 (13)	C11—C10—C15	121.37 (13)
O4—N4—C14	119.64 (13)	C9—C10—C15	119.09 (13)
N1—C1—C6	124.71 (14)	C10—C11—C12	123.78 (13)
N1—C1—C2	118.94 (13)	C10—C11—H11	118.1
C6—C1—C2	116.34 (12)	C12—C11—H11	118.1
C3—C2—C1	119.62 (13)	C13—C12—C11	117.26 (13)
C3—C2—C7	121.49 (14)	C13—C12—C16	121.80 (14)
C1—C2—C7	118.88 (13)	C11—C12—C16	120.93 (13)
C2—C3—C4	123.61 (14)	C12—C13—C14	120.61 (14)
C2—C3—H3	118.2	C12—C13—H13	119.7
C4—C3—H3	118.2	C14—C13—H13	119.7
C5—C4—C3	117.38 (13)	C13—C14—C9	122.58 (13)
C5—C4—C8	121.84 (13)	C13—C14—N4	116.04 (13)
C3—C4—C8	120.78 (14)	C9—C14—N4	121.33 (13)
C4—C5—C6	120.99 (13)	C10—C15—H15A	109.5
C4—C5—H5	119.5	C10—C15—H15B	109.5
C6—C5—H5	119.5	H15A—C15—H15B	109.5
C5—C6—C1	122.03 (13)	C10—C15—H15C	109.5
C5—C6—N2	116.66 (12)	H15A—C15—H15C	109.5
C1—C6—N2	121.31 (12)	H15B—C15—H15C	109.5
C2—C7—H7A	109.5	C12—C16—H16A	109.5
C2—C7—H7B	109.5	C12—C16—H16B	109.5
H7A—C7—H7B	109.5	H16A—C16—H16B	109.5
C2—C7—H7C	109.5	C12—C16—H16C	109.5
H7A—C7—H7C	109.5	H16A—C16—H16C	109.5
H7B—C7—H7C	109.5	H16B—C16—H16C	109.5

N1—C1—C2—C3	179.68 (12)	N3—C9—C10—C11	179.60 (13)
C6—C1—C2—C3	−1.15 (19)	C14—C9—C10—C11	1.34 (19)
N1—C1—C2—C7	−1.48 (19)	N3—C9—C10—C15	−0.11 (19)
C6—C1—C2—C7	177.69 (12)	C14—C9—C10—C15	−178.37 (12)
C1—C2—C3—C4	−0.2 (2)	C9—C10—C11—C12	−0.9 (2)
C7—C2—C3—C4	−178.98 (14)	C15—C10—C11—C12	178.82 (13)
C2—C3—C4—C5	1.4 (2)	C10—C11—C12—C13	0.0 (2)
C2—C3—C4—C8	−178.87 (13)	C10—C11—C12—C16	179.93 (13)
C3—C4—C5—C6	−1.3 (2)	C11—C12—C13—C14	0.36 (19)
C8—C4—C5—C6	179.02 (13)	C16—C12—C13—C14	−179.57 (13)
C4—C5—C6—C1	−0.1 (2)	C12—C13—C14—C9	0.2 (2)
C4—C5—C6—N2	179.65 (12)	C12—C13—C14—N4	177.77 (12)
N1—C1—C6—C5	−179.59 (13)	N3—C9—C14—C13	−179.16 (13)
C2—C1—C6—C5	1.29 (19)	C10—C9—C14—C13	−1.03 (19)
N1—C1—C6—N2	0.7 (2)	N3—C9—C14—N4	3.4 (2)
C2—C1—C6—N2	−178.42 (12)	C10—C9—C14—N4	−178.49 (12)
O1—N2—C6—C5	2.09 (19)	O3—N4—C14—C13	1.16 (19)
O2—N2—C6—C5	−177.89 (12)	O4—N4—C14—C13	−178.08 (13)
O1—N2—C6—C1	−178.19 (12)	O3—N4—C14—C9	178.78 (14)
O2—N2—C6—C1	1.8 (2)	O4—N4—C14—C9	−0.5 (2)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O3	0.91 (2)	2.27 (2)	3.166 (2)	167.9 (18)
N3—H3B···O4	0.93 (2)	1.92 (2)	2.631 (2)	131.3 (17)
N3—H3A···O2ⁱ	0.89 (2)	2.30 (2)	3.1667 (19)	165.8 (17)
N1—H1B···O2	0.86 (2)	1.972 (18)	2.6233 (19)	131.4 (16)

Symmetry code: (i) −x+1, y−1/2, −z+3/2.

Experimental details

Crystal data
Chemical formula	C₈H₁₀N₂O₂
M_r	166.18
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	163
a, b, c (Å)	6.997 (2), 14.919 (4), 15.907 (5)
β (°)	101.176 (4)
V (Å³)	1629.1 (8)
Z	8
Radiation type	Mo Kα
µ (mm⁻¹)	0.10
Crystal size (mm)	0.37 × 0.35 × 0.24

Data collection
Diffractometer	Rigaku AFC10/Saturn724+ diffractometer
Absorption correction	–
No. of measured, independent and observed [I > 2σ(I)] reflections	10540, 4325, 3104
R_int	0.027
(sin θ/λ)_max (Å⁻¹)	0.684

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.049, 0.134, 1.00
No. of reflections	4325
No. of parameters	237
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.32, −0.21

Computer programs: CrystalClear (Rigaku/MSC, 2008), 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
N1—H1A···O3	0.91 (2)	2.27 (2)	3.166 (2)	167.9 (18)
N3—H3B···O4	0.93 (2)	1.92 (2)	2.631 (2)	131.3 (17)
N3—H3A···O2ⁱ	0.89 (2)	2.30 (2)	3.1667 (19)	165.8 (17)
N1—H1B···O2	0.86 (2)	1.972 (18)	2.6233 (19)	131.4 (16)

Symmetry code: (i) −x+1, y−1/2, −z+3/2.

Acknowledgements

This work was supported by the Science Research Foundation of Baoji University of Arts and Sciences (No. ZK1050)

References

Hu, S.-W., Rong, Z.-M. & Liu, Y.-C. (2010). Fine Chem. 27, 170–173. CAS Google Scholar
Liang, C. (2000). Jiangsu Chem. Eng. 28, 17–19. Google Scholar
Qi, L., Pang, S.-P. & Sun, C.-H. (2009). Chin. J. Energ. Mater. 17, 4–6. CAS Google Scholar
Qian, C.-L. (2005). Text. Chem. 3, 68–71. Google Scholar
Rigaku/MSC (2008). 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