1-Methyl-4,5-dinitro-1H-imidazole

Abstract

In the title compound, C₄H₄N₄O₄, the two nitro groups are twisted with respect to the imidazole plane, making dihedral angles of 24.2 (3) and 33.4 (4)°. In the crystal structure, the mol­ecules are linked through non-classical inter­molecular C—H⋯O hydrogen bonds.

Related literature

For the synthesis, see: Damavarapu et al. (2007 ▶). For the biological activity of polynitro­imidazole systems, see: Hofmann (1953 ▶); Breccia et al. (1982 ▶); Boyer (1986 ▶). For their detonation performance, see: Storm et al. (1990 ▶); Katritzky et al. (1993 ▶); Bulusu et al. (1995 ▶).

Experimental

Crystal data

• C₄H₄N₄O₄

• M _r = 172.11

• Orthorhombic,

• a = 8.412 (2) Å

• b = 12.646 (3) Å

• c = 6.563 (1) Å

• V = 698.2 (3) ų

• Z = 4

• Mo Kα radiation

• μ = 0.15 mm⁻¹

• T = 293 K

• 0.40 × 0.30 × 0.20 mm

Data collection

• Rigaku R-AXIS RAPID IP diffractometer

• Absorption correction: multi-scan (ABSCOR; Higashi, 1995 ▶) T _min = 0.944, T _max = 0.971

• 3573 measured reflections

• 871 independent reflections

• 648 reflections with I > 2σ(I)

• R _int = 0.097

Refinement

• R[F ² > 2σ(F ²)] = 0.046

• wR(F ²) = 0.112

• S = 0.95

• 871 reflections

• 111 parameters

• 1 restraint

• H-atom parameters constrained

• Δρ_max = 0.22 e Å⁻³

• Δρ_min = −0.18 e Å⁻³

Data collection: RAPID-AUTO (Rigaku, 2000 ▶); cell refinement: RAPID-AUTO; data reduction: CrystalStructure (Rigaku, 2000 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶) and DIAMOND (Brandenburg, 1998 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Enhanced figure: interactive version of Fig. 1

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C1—H1⋯O1i	0.93	2.49	3.150 (4)	128
C4—H4A⋯O4ii	0.96	2.48	3.428 (5)	170

Symmetry codes: (i) ; (ii) .

supplementary crystallographic information

Comment

Polynitroimidazole systems have been investigated extensively owing to their biological activity (Hofmann, 1953; Breccia et al., 1982; Boyer, 1986). Recently, these so called "high energy density materials" have attracted renewed attention in conjunction with their favorable detonation performance (Storm et al., 1990; Katritzky et al., 1993; Bulusu et al., 1995). As a promising candidate, 1-methyl-4,5- dinitroimidazole was synthesized by the nitration of N-methyl- imidazole (Damavarapu et al., 2007). Here we reprot the crystal structure of the title compound (Fig. 1).

In the crystal structure, the two nitro groups are twisted with respect to the imidazole plane, making dihedral angles of 24.2 (3)° (N3/O1, O2) and 33.4 (4)° (N4/O3, O4). The molecular packing (Fig. 2) is stabilized by non-classical intermolecular C–H···O hydrogen bonds; the first between the imidazole H atom and an oxygen of the nitro group, with C1–H1···Oⁱ, the second between the methyl H atom and an oxygen of the nitro group, with C4–H4A···O4ⁱⁱ, respectively (Table 1).

Experimental

The title compound was prepared according to literature method (Damavarapu et al., 2007). Single crystals suitable for X-ray diffraction were obtained by evaporation of a solution of the title compound in methanol at room temperature.

Refinement

All the Friedel pairs were merged. All H atoms were positioned geometrically and treated as riding, with C–H bond lengths constrained to 0.93 ° for imidazole ring H and 0.96 ° for methyl H atoms, and with U_iso(H) = 1.2U_eq(C) for imidazole ring H atom and 1.5U_eq(C) for methyl H atoms.

Figures

Fig. 1.

The molecular structure of the title compound with the atom numbering scheme. Displacement ellipsoids are drawn at the 30% probability level. H atoms are presented as a small spheres of arbitrary radius.

Fig. 2.

C–H···O interactions (dotted lines) in the crystal structure of the title compound. [Symmetry codes: (i) - x + 1/2, y + 1/2, z - 1/2; (ii) x + 1/2, - y + 3/2, z - 1; (iii) - x + 1/2, y - 1/2, z + 1/2; (iv) x - 1/2, - y + 3/2, z + 1.]

Crystal data

C4H4N4O4	F(000) = 352
Mr = 172.11	Dx = 1.637 Mg m−3
Orthorhombic, Pna21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2n	Cell parameters from 3573 reflections
a = 8.412 (2) Å	θ = 2.9–27.6°
b = 12.646 (3) Å	µ = 0.15 mm−1
c = 6.563 (1) Å	T = 293 K
V = 698.2 (3) Å3	Block, colorless
Z = 4	0.40 × 0.30 × 0.20 mm

Data collection

Rigaku R-AXIS RAPID IP diffractometer	871 independent reflections
Radiation source: fine-focus sealed tube	648 reflections with I > 2σ(I)
graphite	Rint = 0.097
Detector resolution: 10.00 pixels mm-1	θmax = 27.6°, θmin = 2.9°
ω scans	h = −10→10
Absorption correction: multi-scan (ABSCOR; Higashi, 1995)	k = −16→16
Tmin = 0.944, Tmax = 0.971	l = −8→8
3573 measured reflections

Refinement

Refinement on F2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.046	H-atom parameters constrained
wR(F2) = 0.112	w = 1/[σ2(Fo2) + (0.075P)2] where P = (Fo2 + 2Fc2)/3
S = 0.95	(Δ/σ)max = 0.001
871 reflections	Δρmax = 0.22 e Å−3
111 parameters	Δρmin = −0.18 e Å−3
1 restraint	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.147 (18)

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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
C1	0.2730 (4)	0.7411 (2)	0.2853 (6)	0.0530 (8)
H1	0.3251	0.7751	0.1789	0.064*
C2	0.1370 (3)	0.7145 (2)	0.5486 (5)	0.0449 (7)
C3	0.1843 (3)	0.61741 (19)	0.4808 (5)	0.0378 (6)
C4	0.3530 (4)	0.5610 (3)	0.1731 (6)	0.0607 (9)
H4A	0.3955	0.5988	0.0585	0.091*
H4B	0.2780	0.5092	0.1262	0.091*
H4C	0.4377	0.5264	0.2447	0.091*
N1	0.2728 (2)	0.63562 (17)	0.3106 (4)	0.0410 (6)
N2	0.1915 (4)	0.79129 (19)	0.4271 (5)	0.0561 (7)
N3	0.1551 (3)	0.51403 (18)	0.5576 (4)	0.0490 (7)
N4	0.0529 (3)	0.7419 (2)	0.7316 (5)	0.0569 (7)
O1	0.2496 (3)	0.44510 (19)	0.5115 (6)	0.0806 (9)
O2	0.0370 (3)	0.5008 (2)	0.6601 (5)	0.0773 (9)
O3	0.0716 (4)	0.6874 (3)	0.8832 (5)	0.0878 (10)
O4	−0.0300 (3)	0.8211 (2)	0.7273 (6)	0.0839 (10)

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
C1	0.0718 (17)	0.0401 (15)	0.0470 (18)	−0.0025 (13)	0.0072 (16)	0.0127 (15)
C2	0.0424 (13)	0.0501 (16)	0.0421 (16)	0.0026 (10)	−0.0036 (12)	−0.0010 (13)
C3	0.0393 (12)	0.0394 (13)	0.0346 (13)	−0.0021 (9)	−0.0019 (11)	0.0059 (11)
C4	0.0676 (18)	0.0527 (19)	0.062 (2)	0.0108 (14)	0.0197 (17)	0.0053 (17)
N1	0.0471 (10)	0.0376 (12)	0.0384 (12)	0.0002 (9)	0.0032 (11)	0.0074 (11)
N2	0.0737 (16)	0.0423 (14)	0.0524 (18)	0.0039 (11)	0.0002 (15)	0.0042 (12)
N3	0.0560 (13)	0.0463 (14)	0.0446 (15)	−0.0099 (11)	−0.0002 (13)	0.0116 (12)
N4	0.0537 (13)	0.0690 (17)	0.0479 (16)	−0.0004 (14)	−0.0017 (13)	−0.0132 (15)
O1	0.0872 (16)	0.0502 (13)	0.104 (3)	0.0139 (11)	0.0169 (18)	0.0335 (15)
O2	0.0832 (18)	0.0780 (17)	0.071 (2)	−0.0301 (13)	0.0296 (16)	0.0049 (14)
O3	0.116 (2)	0.098 (2)	0.0499 (17)	0.0005 (17)	0.0167 (17)	0.0044 (15)
O4	0.0717 (14)	0.106 (2)	0.074 (2)	0.0307 (13)	−0.0068 (15)	−0.0273 (19)

Geometric parameters (Å, °)

C1—N2	1.318 (5)	C4—N1	1.470 (4)
C1—N1	1.344 (4)	C4—H4A	0.9600
C1—H1	0.9300	C4—H4B	0.9600
C2—N2	1.337 (4)	C4—H4C	0.9600
C2—C3	1.365 (4)	N3—O2	1.212 (3)
C2—N4	1.436 (4)	N3—O1	1.218 (4)
C3—N1	1.361 (4)	N4—O3	1.220 (5)
C3—N3	1.423 (3)	N4—O4	1.222 (4)
N2—C1—N1	112.9 (3)	H4A—C4—H4C	109.5
N2—C1—H1	123.5	H4B—C4—H4C	109.5
N1—C1—H1	123.5	C1—N1—C3	105.7 (2)
N2—C2—C3	111.0 (3)	C1—N1—C4	124.1 (3)
N2—C2—N4	119.5 (3)	C3—N1—C4	130.2 (2)
C3—C2—N4	129.2 (3)	C1—N2—C2	104.5 (2)
N1—C3—C2	105.9 (2)	O2—N3—O1	125.1 (3)
N1—C3—N3	122.7 (2)	O2—N3—C3	117.8 (3)
C2—C3—N3	131.3 (3)	O1—N3—C3	117.2 (3)
N1—C4—H4A	109.5	O3—N4—O4	123.8 (4)
N1—C4—H4B	109.5	O3—N4—C2	118.8 (3)
H4A—C4—H4B	109.5	O4—N4—C2	117.3 (3)
N1—C4—H4C	109.5
N2—C2—C3—N1	0.4 (3)	C3—C2—N2—C1	−0.3 (4)
N4—C2—C3—N1	−174.1 (3)	N4—C2—N2—C1	174.8 (3)
N2—C2—C3—N3	−179.5 (3)	N1—C3—N3—O2	−155.1 (3)
N4—C2—C3—N3	6.0 (5)	C2—C3—N3—O2	24.8 (5)
N2—C1—N1—C3	0.2 (4)	N1—C3—N3—O1	23.5 (4)
N2—C1—N1—C4	179.3 (3)	C2—C3—N3—O1	−156.6 (3)
C2—C3—N1—C1	−0.3 (3)	N2—C2—N4—O3	−143.7 (4)
N3—C3—N1—C1	179.6 (3)	C3—C2—N4—O3	30.5 (5)
C2—C3—N1—C4	−179.4 (3)	N2—C2—N4—O4	34.1 (4)
N3—C3—N1—C4	0.5 (5)	C3—C2—N4—O4	−151.8 (3)
N1—C1—N2—C2	0.1 (4)

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
C1—H1···O1i	0.93	2.49	3.150 (4)	128
C4—H4A···O4ii	0.96	2.48	3.428 (5)	170

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