organic compounds
H-imidazole
of 4,5-dinitro-1aPO Box 1663 MS C920, Los Alamos National Laboratory, Los Alamos, NM 87544, USA, and bPO Box 1663 MS J514, Los Alamos National Laboratory, Los Alamos, NM 87544, USA
*Correspondence e-mail: philipl@lanl.gov
The title compound, C3H2N4O4, forms crystals with two molecules in the which are conformationally similar. With the exception of the O atoms of the nitro groups, the molecules are essentially planar. In the crystal, adjacent molecules are associated by N—H⋯N hydrogen bonds involving the imidazole N—H donors and N-atom acceptors of the unsaturated nitrogen of neighboring rings, forming layers parallel to (010).
Keywords: crystal structure; 4,5-dinitro-1H-imidazole; hydrogen bonding.
CCDC reference: 1412685
1. Related literature
For background to imidazoles and the title compound, see: Windaus & Vogt (1907); Cooper (1996); Epishina et al. (1967). For the preparation, see: Novikov et al. (1970). For similar structures, see: Parrish et al. (2015); Windler et al. (2015).
2. Experimental
2.1. Crystal data
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2.3. Refinement
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Data collection: APEX2 (Bruker, 2009); cell SAINT (Bruker, 2009); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012), Mercury (Macrae et al., 2008) and PLATON (Spek, 2009); software used to prepare material for publication: CHEMDRAW Ultra (Cambridge Soft, 2014).
Supporting information
CCDC reference: 1412685
https://doi.org/10.1107/S2056989015013432/zs2338sup1.cif
contains datablock I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989015013432/zs2338Isup2.hkl
Supporting information file. DOI: https://doi.org/10.1107/S2056989015013432/zs2338Isup3.cdx
Supporting information file. DOI: https://doi.org/10.1107/S2056989015013432/zs2338Isup4.cml
Caution! The title compound is an explosive and should only be handled with appropriate safety equipment in small quantities by an experienced explosive handler.
The title compound was prepared by literature methods (Novikov et al., 1970). Crystals were obtained by slow evaporation of a concentrated solution in ethyl acetate.
All hydrogen atoms was located in a difference-Fourier and the positional parameters were fully refined, with Uiso(H) set invariant at 0.08.
In addition to more mundane uses as pharmaceuticals (Windaus & Vogt, 1907), imidazoles make quality backbones for energetic materials (Epishina et al., 1967) because of their nitrogen content. The dinitro-bearing title compound, C3H2N4O4, is of interest because of its better oxygen balance (Cooper, 1996), contributing to its effectiveness as an explosive. To better understand the nature of explosive sensitivity as it relates to intermolecular forces, the title compound (Fig. 1) was of interest for comparison with other imidazoles previously studied (Parrish et al., 2015; Windler et al., 2015).
In the title compound, the two independent molecules (A, defined by C1–N3 and B, defined by C4–N7) in the
(Fig. 1) are conformationally similar with the nitro groups being variously rotated out of the imidazole planes: in A [torsion angles N3—C1—N1—O2, -174.29 (9)° and N4—C3—N2—O3, 163.63 (7)°] and in B [torsion angles N7—C4—N5—O6, 156.95 (8)° and N6—C6—N6—O7, 163.63 (7)°].In the crystal, intermolecular N—H···N hydrogen bonding interactions N3—H···N7 and N8—H···N4 between the A and B molecules (Table 1), generate layered structures lying roughly parallel to (010) (Fig. 2).
For background to imidazoles and the title compound, see: Windaus & Vogt (1907); Cooper (1996); Epishina et al. (1967). For the preparation, see: Novikov et al. (1970). For similar structures, see: Parrish et al. (2015); Windler et al. (2015).
Data collection: APEX2 (Bruker, 2009); cell
SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012), Mercury (Macrae et al., 2008) and PLATON (Spek, 2009); software used to prepare material for publication: CHEMDRAW Ultra (Cambridge Soft, 2014).C3H2N4O4 | F(000) = 640 |
Mr = 158.09 | Dx = 1.846 Mg m−3 |
Monoclinic, P21/n | Melting point = 460–461 K |
Hall symbol: -P 2yn | Mo Kα radiation, λ = 0.71073 Å |
a = 11.4797 (9) Å | Cell parameters from 4868 reflections |
b = 8.8205 (7) Å | θ = 2.9–35.4° |
c = 11.802 (1) Å | µ = 0.17 mm−1 |
β = 107.827 (1)° | T = 100 K |
V = 1137.65 (16) Å3 | Block, colorless |
Z = 8 | 0.12 × 0.06 × 0.06 mm |
Bruker D8 Quest with CMOS diffractometer | 4868 independent reflections |
Radiation source: fine-focus sealed tube | 4216 reflections with I > 2σ(I) |
Bruker Triumph curved graphite monochromator | Rint = 0.024 |
ω scans | θmax = 35.4°, θmin = 2.9° |
Absorption correction: multi-scan (SADABS; Bruker, 2009) | h = −17→18 |
Tmin = 0.971, Tmax = 0.995 | k = −14→13 |
25837 measured reflections | l = −18→18 |
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)] = 0.037 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.118 | All H-atom parameters refined |
S = 1.60 | w = 1/[σ2(Fo2) + (0.0548P)2] where P = (Fo2 + 2Fc2)/3 |
4868 reflections | (Δ/σ)max = 0.001 |
211 parameters | Δρmax = 0.54 e Å−3 |
0 restraints | Δρmin = −0.33 e Å−3 |
C3H2N4O4 | V = 1137.65 (16) Å3 |
Mr = 158.09 | Z = 8 |
Monoclinic, P21/n | Mo Kα radiation |
a = 11.4797 (9) Å | µ = 0.17 mm−1 |
b = 8.8205 (7) Å | T = 100 K |
c = 11.802 (1) Å | 0.12 × 0.06 × 0.06 mm |
β = 107.827 (1)° |
Bruker D8 Quest with CMOS diffractometer | 4868 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2009) | 4216 reflections with I > 2σ(I) |
Tmin = 0.971, Tmax = 0.995 | Rint = 0.024 |
25837 measured reflections |
R[F2 > 2σ(F2)] = 0.037 | 0 restraints |
wR(F2) = 0.118 | All H-atom parameters refined |
S = 1.60 | Δρmax = 0.54 e Å−3 |
4868 reflections | Δρmin = −0.33 e Å−3 |
211 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
N1 | 0.29370 (6) | 0.50168 (8) | 0.81909 (6) | 0.01298 (13) | |
N2 | 0.15331 (6) | 0.38337 (8) | 1.01582 (6) | 0.01315 (13) | |
N3 | 0.11402 (6) | 0.37089 (8) | 0.70000 (6) | 0.01075 (12) | |
N4 | 0.01562 (6) | 0.30341 (8) | 0.82719 (6) | 0.01203 (13) | |
N5 | 0.51594 (6) | 0.79131 (8) | 0.14048 (6) | 0.01209 (13) | |
N6 | 0.33377 (6) | 0.62492 (8) | 0.27135 (6) | 0.01158 (12) | |
N7 | 0.31591 (6) | 0.85813 (8) | 0.01033 (6) | 0.01174 (12) | |
N8 | 0.19372 (6) | 0.75974 (8) | 0.10560 (6) | 0.01083 (12) | |
O1 | 0.31536 (6) | 0.52596 (8) | 0.72497 (6) | 0.02044 (14) | |
O2 | 0.35443 (7) | 0.54920 (9) | 0.91643 (6) | 0.02736 (17) | |
O3 | 0.25949 (6) | 0.41102 (8) | 1.07370 (6) | 0.01982 (14) | |
O4 | 0.06957 (6) | 0.36304 (9) | 1.05882 (6) | 0.02084 (14) | |
O5 | 0.55956 (6) | 0.80860 (9) | 0.05851 (6) | 0.02079 (14) | |
O6 | 0.57642 (6) | 0.78190 (8) | 0.24607 (5) | 0.01798 (13) | |
O7 | 0.43309 (5) | 0.56137 (7) | 0.30593 (6) | 0.01585 (12) | |
O8 | 0.24913 (6) | 0.60769 (8) | 0.31361 (6) | 0.01785 (13) | |
C1 | 0.18544 (7) | 0.41388 (8) | 0.81011 (6) | 0.01016 (13) | |
C2 | 0.01380 (7) | 0.30381 (9) | 0.71412 (7) | 0.01240 (14) | |
C3 | 0.12271 (7) | 0.37018 (8) | 0.88769 (6) | 0.01062 (13) | |
C4 | 0.38434 (7) | 0.78740 (8) | 0.11035 (6) | 0.01003 (13) | |
C5 | 0.20090 (7) | 0.83961 (9) | 0.01039 (7) | 0.01204 (14) | |
C6 | 0.31069 (7) | 0.72465 (8) | 0.17067 (6) | 0.00992 (13) | |
H1 | −0.044 (2) | 0.259 (3) | 0.651 (2) | 0.080* | |
H2 | 0.129 (2) | 0.386 (3) | 0.630 (2) | 0.080* | |
H3 | 0.133 (2) | 0.875 (3) | −0.045 (2) | 0.080* | |
H4 | 0.125 (2) | 0.740 (3) | 0.1274 (19) | 0.080* |
U11 | U22 | U33 | U12 | U13 | U23 | |
N1 | 0.0108 (3) | 0.0118 (3) | 0.0163 (3) | −0.0018 (2) | 0.0041 (2) | −0.0016 (2) |
N2 | 0.0163 (3) | 0.0130 (3) | 0.0101 (3) | 0.0017 (2) | 0.0039 (2) | 0.0008 (2) |
N3 | 0.0099 (3) | 0.0133 (3) | 0.0102 (3) | −0.0015 (2) | 0.0047 (2) | −0.0021 (2) |
N4 | 0.0110 (3) | 0.0151 (3) | 0.0109 (3) | −0.0013 (2) | 0.0047 (2) | −0.0008 (2) |
N5 | 0.0099 (3) | 0.0128 (3) | 0.0138 (3) | −0.0012 (2) | 0.0039 (2) | 0.0000 (2) |
N6 | 0.0119 (3) | 0.0126 (3) | 0.0100 (3) | −0.0010 (2) | 0.0031 (2) | 0.0009 (2) |
N7 | 0.0108 (3) | 0.0154 (3) | 0.0098 (3) | 0.0015 (2) | 0.0042 (2) | 0.0018 (2) |
N8 | 0.0089 (3) | 0.0147 (3) | 0.0096 (3) | 0.0004 (2) | 0.0038 (2) | 0.0005 (2) |
O1 | 0.0205 (3) | 0.0243 (3) | 0.0221 (3) | −0.0084 (2) | 0.0147 (2) | −0.0065 (2) |
O2 | 0.0271 (4) | 0.0329 (4) | 0.0170 (3) | −0.0173 (3) | −0.0009 (3) | −0.0019 (3) |
O3 | 0.0195 (3) | 0.0229 (3) | 0.0135 (3) | −0.0047 (2) | −0.0003 (2) | −0.0017 (2) |
O4 | 0.0197 (3) | 0.0315 (4) | 0.0139 (3) | 0.0045 (3) | 0.0091 (2) | 0.0044 (2) |
O5 | 0.0135 (3) | 0.0340 (4) | 0.0182 (3) | −0.0032 (2) | 0.0097 (2) | −0.0037 (2) |
O6 | 0.0123 (3) | 0.0222 (3) | 0.0156 (3) | −0.0039 (2) | −0.0014 (2) | 0.0056 (2) |
O7 | 0.0114 (2) | 0.0170 (3) | 0.0171 (3) | 0.0014 (2) | 0.0013 (2) | 0.0044 (2) |
O8 | 0.0166 (3) | 0.0229 (3) | 0.0173 (3) | 0.0010 (2) | 0.0099 (2) | 0.0062 (2) |
C1 | 0.0093 (3) | 0.0104 (3) | 0.0113 (3) | −0.0006 (2) | 0.0039 (2) | −0.0013 (2) |
C2 | 0.0105 (3) | 0.0162 (3) | 0.0118 (3) | −0.0022 (2) | 0.0053 (2) | −0.0021 (2) |
C3 | 0.0111 (3) | 0.0118 (3) | 0.0093 (3) | 0.0004 (2) | 0.0037 (2) | −0.0004 (2) |
C4 | 0.0086 (3) | 0.0120 (3) | 0.0097 (3) | 0.0000 (2) | 0.0031 (2) | −0.0006 (2) |
C5 | 0.0109 (3) | 0.0157 (3) | 0.0100 (3) | 0.0021 (2) | 0.0040 (2) | 0.0016 (2) |
C6 | 0.0095 (3) | 0.0121 (3) | 0.0080 (3) | 0.0000 (2) | 0.0025 (2) | 0.0005 (2) |
O1—N1 | 1.2291 (10) | N4—C3 | 1.3530 (11) |
O2—N1 | 1.2211 (10) | N3—H2 | 0.90 (2) |
O3—N2 | 1.2256 (10) | N5—C4 | 1.4426 (11) |
O4—N2 | 1.2299 (10) | N6—C6 | 1.4364 (10) |
O5—N5 | 1.2274 (10) | N7—C5 | 1.3306 (11) |
O6—N5 | 1.2297 (9) | N7—C4 | 1.3535 (10) |
O7—N6 | 1.2230 (10) | N8—C6 | 1.3628 (11) |
O8—N6 | 1.2299 (10) | N8—C5 | 1.3500 (11) |
N1—C1 | 1.4404 (11) | N8—H4 | 0.92 (2) |
N2—C3 | 1.4486 (10) | C1—C3 | 1.3817 (11) |
N3—C1 | 1.3610 (10) | C2—H1 | 0.92 (2) |
N3—C2 | 1.3487 (11) | C4—C6 | 1.3771 (11) |
N4—C2 | 1.3282 (10) | C5—H3 | 0.91 (2) |
O1—N1—O2 | 125.12 (8) | C6—N8—H4 | 125.6 (14) |
O1—N1—C1 | 115.84 (7) | N1—C1—C3 | 135.58 (7) |
O2—N1—C1 | 119.01 (7) | N3—C1—C3 | 105.73 (7) |
O3—N2—O4 | 124.66 (7) | N1—C1—N3 | 118.30 (6) |
O3—N2—C3 | 118.67 (7) | N3—C2—N4 | 111.94 (7) |
O4—N2—C3 | 116.66 (7) | N2—C3—C1 | 131.32 (7) |
C1—N3—C2 | 106.95 (7) | N4—C3—C1 | 110.21 (6) |
C2—N4—C3 | 105.15 (7) | N2—C3—N4 | 118.47 (7) |
C1—N3—H2 | 127.2 (15) | N3—C2—H1 | 121.3 (15) |
C2—N3—H2 | 125.9 (15) | N4—C2—H1 | 126.7 (15) |
O5—N5—C4 | 117.25 (7) | N7—C4—C6 | 110.60 (7) |
O6—N5—C4 | 118.16 (7) | N5—C4—N7 | 119.23 (7) |
O5—N5—O6 | 124.55 (8) | N5—C4—C6 | 130.13 (7) |
O8—N6—C6 | 116.27 (7) | N7—C5—N8 | 112.21 (7) |
O7—N6—C6 | 118.28 (7) | N8—C6—C4 | 105.81 (6) |
O7—N6—O8 | 125.42 (7) | N6—C6—N8 | 120.37 (7) |
C4—N7—C5 | 104.72 (7) | N6—C6—C4 | 133.38 (7) |
C5—N8—C6 | 106.67 (7) | N7—C5—H3 | 126.3 (15) |
C5—N8—H4 | 127.5 (14) | N8—C5—H3 | 121.5 (15) |
O1—N1—C1—N3 | −2.71 (11) | O7—N6—C6—N8 | 159.07 (7) |
O1—N1—C1—C3 | −174.29 (9) | O7—N6—C6—C4 | −12.11 (12) |
O2—N1—C1—N3 | 175.41 (8) | O8—N6—C6—N8 | −18.96 (10) |
O2—N1—C1—C3 | 3.83 (14) | O8—N6—C6—C4 | 169.86 (8) |
O3—N2—C3—N4 | 163.63 (7) | C4—N7—C5—N8 | −0.32 (9) |
O3—N2—C3—C1 | −15.76 (12) | C5—N7—C4—N5 | −177.47 (7) |
O4—N2—C3—N4 | −15.16 (11) | C5—N7—C4—C6 | 0.55 (9) |
O4—N2—C3—C1 | 165.45 (8) | C5—N8—C6—N6 | −173.00 (7) |
C2—N3—C1—N1 | −174.24 (7) | C5—N8—C6—C4 | 0.35 (8) |
C2—N3—C1—C3 | −0.35 (8) | C6—N8—C5—N7 | −0.02 (9) |
C1—N3—C2—N4 | 1.06 (9) | N3—C1—C3—N4 | −0.44 (9) |
C3—N4—C2—N3 | −1.31 (9) | N1—C1—C3—N2 | −8.71 (15) |
C2—N4—C3—N2 | −178.45 (7) | N1—C1—C3—N4 | 171.86 (8) |
C2—N4—C3—C1 | 1.06 (9) | N3—C1—C3—N2 | 178.98 (8) |
O6—N5—C4—C6 | −25.25 (12) | N5—C4—C6—N6 | −10.74 (14) |
O5—N5—C4—N7 | −25.48 (11) | N5—C4—C6—N8 | 177.17 (7) |
O5—N5—C4—C6 | 156.95 (8) | N7—C4—C6—N6 | 171.53 (8) |
O6—N5—C4—N7 | 152.33 (7) | N7—C4—C6—N8 | −0.57 (8) |
D—H···A | D—H | H···A | D···A | D—H···A |
N3—H2···N7i | 0.90 (2) | 1.96 (2) | 2.836 (1) | 163 (2) |
N8—H4···N4ii | 0.92 (2) | 1.89 (2) | 2.807 (1) | 179 (3) |
Symmetry codes: (i) −x+1/2, y−1/2, −z+1/2; (ii) −x, −y+1, −z+1. |
D—H···A | D—H | H···A | D···A | D—H···A |
N3—H2···N7i | 0.90 (2) | 1.96 (2) | 2.836 (1) | 163 (2) |
N8—H4···N4ii | 0.92 (2) | 1.89 (2) | 2.807 (1) | 179 (3) |
Symmetry codes: (i) −x+1/2, y−1/2, −z+1/2; (ii) −x, −y+1, −z+1. |
Acknowledgements
This work was supported by the National Nuclear Security Administration Science Campaign 2 and performed at Los Alamos National Laboratory under DE-AC52-06 N A25396. LA-UR-15-23929
References
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This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
In addition to more mundane uses as pharmaceuticals (Windaus & Vogt, 1907), imidazoles make quality backbones for energetic materials (Epishina et al., 1967) because of their nitrogen content. The dinitro-bearing title compound, C3H2N4O4, is of interest because of its better oxygen balance (Cooper, 1996), contributing to its effectiveness as an explosive. To better understand the nature of explosive sensitivity as it relates to intermolecular forces, the title compound (Fig. 1) was of interest for comparison with other imidazoles previously studied (Parrish et al., 2015; Windler et al., 2015).
In the title compound, the two independent molecules (A, defined by C1–N3 and B, defined by C4–N7) in the asymmetric unit (Fig. 1) are conformationally similar with the nitro groups being variously rotated out of the imidazole planes: in A [torsion angles N3—C1—N1—O2, -174.29 (9)° and N4—C3—N2—O3, 163.63 (7)°] and in B [torsion angles N7—C4—N5—O6, 156.95 (8)° and N6—C6—N6—O7, 163.63 (7)°].
In the crystal, intermolecular N—H···N hydrogen bonding interactions N3—H···N7 and N8—H···N4 between the A and B molecules (Table 1), generate layered structures lying roughly parallel to (010) (Fig. 2).