Acta Cryst. (2008). E64, o745 [ doi:10.1107/S1600536808007514 ]
The title compound, C7H6N4O4, plays an important role in the synthesis of biologically active compounds. The planar hydrazone group is oriented at a dihedral angle of 8.27 (3)° with respect to the benzene ring. In the crystal structure, intermolecular N-H
O and N-HN hydrogen bonds link the molecules.
2,4-Dinitrobenzaldehyde (1.96 g, 10 mmol) was dissolved in 100 ml absolute ethanol, after which hydrazine hydrate (0.96 ml, 20 mmol) was added. The mixture was stirred at about 353 K for 5 h. The solution was cooled and kept at about 279 K overnight. Brown powder was collected by filtration (1.41 g, yield 67%) and then single crystals suitable for X-ray measurements were obtained by recrystallization from ethanol.
All non-H atoms were refined anisotropically. All H atoms were placed in calculated positions, with N–H = 0.9 Å and C–H = 0.93 Å. Final difference Fourier maps showed the highest and lowest electron densities of 0.160 and -0.177 e Å-3, respectively.
Data collection: XSCANS (Bruker, 1997); cell refinement: XSCANS (Bruker, 1997); data reduction: XSCANS (Bruker, 1997); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).
![[Figure 1]](./fj2106fig1thm.gif)
| Fig. 1. Perspective drawing of the title compound, with the atomic numbering scheme. Displacement ellipsoids are shown at the 35% probability level. |
![[Figure 2]](./fj2106fig2thm.gif)
| Fig. 2. The unit cell packing of the title compound, viewed along the a direction. |
| C7H6N4O4 | Z = 2 |
| Mr = 210.16 | F000 = 216 |
| Triclinic, P1 | Dx = 1.613 Mg m−3 |
| Hall symbol: -P 1 | Mo Kα radiation λ = 0.71073 Å |
| a = 4.5839 (7) Å | Cell parameters from 39 reflections |
| b = 9.6840 (16) Å | θ = 5.9–12.5º |
| c = 9.9287 (15) Å | µ = 0.14 mm−1 |
| α = 90.785 (12)º | T = 295 (2) K |
| β = 96.149 (11)º | Prism, yellow |
| γ = 98.955 (13)º | 0.4 × 0.3 × 0.2 mm |
| V = 432.66 (12) Å3 |
| Bruker P4 diffractometer | Rint = 0.027 |
| Radiation source: fine-focus sealed tube | θmax = 25.5º |
| Monochromator: graphite | θmin = 2.1º |
| T = 295(2) K | h = −5→1 |
| ω scans | k = −11→11 |
| Absorption correction: none | l = −11→11 |
| 2238 measured reflections | 3 standard reflections |
| 1616 independent reflections | every 97 reflections |
| 1160 reflections with I > 2σ(I) | intensity decay: none |
| Refinement on F2 | Secondary atom site location: difference Fourier map |
| Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
| R[F2 > 2σ(F2)] = 0.048 | H-atom parameters constrained |
| wR(F2) = 0.116 | w = 1/[σ2(Fo2) + (0.001P)2 + 0.38P] where P = (Fo2 + 2Fc2)/3 |
| S = 1.07 | (Δ/σ)max < 0.001 |
| 1616 reflections | Δρmax = 0.16 e Å−3 |
| 136 parameters | Δρmin = −0.18 e Å−3 |
| Primary atom site location: structure-invariant direct methods | Extinction correction: none |
| C7H6N4O4 | γ = 98.955 (13)º |
| Mr = 210.16 | V = 432.66 (12) Å3 |
| Triclinic, P1 | Z = 2 |
| a = 4.5839 (7) Å | Mo Kα |
| b = 9.6840 (16) Å | µ = 0.14 mm−1 |
| c = 9.9287 (15) Å | T = 295 (2) K |
| α = 90.785 (12)º | 0.4 × 0.3 × 0.2 mm |
| β = 96.149 (11)º |
| Bruker P4 diffractometer | Rint = 0.027 |
| Absorption correction: none | 3 standard reflections |
| 2238 measured reflections | every 97 reflections |
| 1616 independent reflections | intensity decay: none |
| 1160 reflections with I > 2σ(I) |
| R[F2 > 2σ(F2)] = 0.048 | 136 parameters |
| wR(F2) = 0.116 | H-atom parameters constrained |
| S = 1.07 | Δρmax = 0.16 e Å−3 |
| 1616 reflections | Δρmin = −0.18 e Å−3 |
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 | ||
| O1 | 0.7840 (6) | 0.1234 (3) | 0.5319 (2) | 0.0887 (8) | |
| O2 | 0.4576 (6) | 0.2314 (2) | 0.6030 (2) | 0.0798 (7) | |
| O3 | 0.0003 (6) | 0.5548 (2) | 0.3362 (3) | 0.0872 (8) | |
| O4 | 0.1241 (6) | 0.5961 (3) | 0.1351 (3) | 0.0946 (9) | |
| N1 | 0.9783 (6) | −0.0870 (3) | 0.1463 (3) | 0.0758 (8) | |
| H1B | 1.0167 | −0.1364 | 0.2204 | 0.091* | |
| H1C | 1.0581 | −0.1043 | 0.0700 | 0.091* | |
| N2 | 0.8489 (5) | 0.0275 (2) | 0.1456 (2) | 0.0578 (6) | |
| N3 | 0.5907 (6) | 0.1955 (2) | 0.5116 (2) | 0.0569 (6) | |
| N4 | 0.1273 (6) | 0.5291 (3) | 0.2381 (3) | 0.0675 (7) | |
| C1 | 0.7626 (6) | 0.0654 (3) | 0.2571 (3) | 0.0520 (7) | |
| H1A | 0.7984 | 0.0169 | 0.3358 | 0.062* | |
| C2 | 0.6075 (6) | 0.1858 (3) | 0.2585 (3) | 0.0471 (6) | |
| C3 | 0.5165 (6) | 0.2445 (3) | 0.3752 (3) | 0.0470 (6) | |
| C4 | 0.3552 (6) | 0.3540 (3) | 0.3687 (3) | 0.0518 (7) | |
| H4A | 0.2918 | 0.3885 | 0.4466 | 0.062* | |
| C5 | 0.2906 (6) | 0.4105 (3) | 0.2464 (3) | 0.0534 (7) | |
| C6 | 0.3755 (6) | 0.3582 (3) | 0.1277 (3) | 0.0580 (7) | |
| H6A | 0.3302 | 0.3978 | 0.0448 | 0.070* | |
| C7 | 0.5269 (6) | 0.2473 (3) | 0.1360 (3) | 0.0561 (7) | |
| H7A | 0.5791 | 0.2108 | 0.0565 | 0.067* |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| O1 | 0.117 (2) | 0.1053 (19) | 0.0558 (13) | 0.0634 (17) | −0.0041 (13) | −0.0040 (12) |
| O2 | 0.1006 (18) | 0.0891 (16) | 0.0580 (13) | 0.0258 (14) | 0.0307 (12) | 0.0011 (11) |
| O3 | 0.0851 (17) | 0.0709 (15) | 0.115 (2) | 0.0314 (13) | 0.0264 (15) | −0.0126 (14) |
| O4 | 0.136 (2) | 0.0714 (16) | 0.0829 (17) | 0.0524 (16) | −0.0107 (16) | 0.0009 (13) |
| N1 | 0.109 (2) | 0.0739 (17) | 0.0583 (15) | 0.0542 (17) | 0.0153 (15) | 0.0001 (13) |
| N2 | 0.0690 (15) | 0.0583 (14) | 0.0517 (14) | 0.0267 (12) | 0.0088 (11) | −0.0026 (11) |
| N3 | 0.0658 (15) | 0.0538 (14) | 0.0513 (14) | 0.0095 (12) | 0.0085 (12) | −0.0042 (11) |
| N4 | 0.0686 (17) | 0.0521 (15) | 0.083 (2) | 0.0200 (13) | −0.0023 (15) | −0.0111 (14) |
| C1 | 0.0609 (17) | 0.0507 (15) | 0.0484 (15) | 0.0176 (13) | 0.0106 (13) | 0.0035 (12) |
| C2 | 0.0447 (14) | 0.0465 (14) | 0.0510 (15) | 0.0082 (11) | 0.0085 (12) | −0.0016 (11) |
| C3 | 0.0482 (15) | 0.0464 (14) | 0.0459 (15) | 0.0056 (12) | 0.0063 (11) | −0.0001 (11) |
| C4 | 0.0494 (15) | 0.0486 (15) | 0.0578 (17) | 0.0080 (12) | 0.0091 (13) | −0.0096 (12) |
| C5 | 0.0505 (15) | 0.0449 (15) | 0.0661 (18) | 0.0140 (12) | 0.0029 (13) | −0.0031 (13) |
| C6 | 0.0649 (18) | 0.0569 (17) | 0.0542 (17) | 0.0183 (14) | 0.0027 (14) | 0.0034 (13) |
| C7 | 0.0661 (18) | 0.0586 (17) | 0.0473 (15) | 0.0211 (14) | 0.0073 (13) | −0.0027 (12) |
| O1—N3 | 1.214 (3) | C1—H1A | 0.9300 |
| O2—N3 | 1.221 (3) | C2—C7 | 1.400 (4) |
| O3—N4 | 1.229 (3) | C2—C3 | 1.414 (3) |
| O4—N4 | 1.219 (3) | C3—C4 | 1.382 (3) |
| N1—N2 | 1.336 (3) | C4—C5 | 1.361 (4) |
| N1—H1B | 0.8999 | C4—H4A | 0.9300 |
| N1—H1C | 0.9000 | C5—C6 | 1.393 (4) |
| N2—C1 | 1.282 (3) | C6—C7 | 1.365 (4) |
| N3—C3 | 1.464 (3) | C6—H6A | 0.9300 |
| N4—C5 | 1.463 (3) | C7—H7A | 0.9300 |
| C1—C2 | 1.458 (3) | ||
| N2—N1—H1B | 124.3 | C4—C3—C2 | 122.2 (2) |
| N2—N1—H1C | 115.3 | C4—C3—N3 | 115.3 (2) |
| H1B—N1—H1C | 119.5 | C2—C3—N3 | 122.5 (2) |
| C1—N2—N1 | 117.5 (2) | C5—C4—C3 | 118.9 (2) |
| O1—N3—O2 | 121.8 (3) | C5—C4—H4A | 120.6 |
| O1—N3—C3 | 119.9 (2) | C3—C4—H4A | 120.6 |
| O2—N3—C3 | 118.3 (2) | C4—C5—C6 | 121.7 (3) |
| O4—N4—O3 | 123.8 (3) | C4—C5—N4 | 119.6 (3) |
| O4—N4—C5 | 118.6 (3) | C6—C5—N4 | 118.7 (3) |
| O3—N4—C5 | 117.6 (3) | C7—C6—C5 | 118.4 (3) |
| N2—C1—C2 | 118.9 (2) | C7—C6—H6A | 120.8 |
| N2—C1—H1A | 120.5 | C5—C6—H6A | 120.8 |
| C2—C1—H1A | 120.5 | C6—C7—C2 | 123.2 (3) |
| C7—C2—C3 | 115.5 (2) | C6—C7—H7A | 118.4 |
| C7—C2—C1 | 119.4 (2) | C2—C7—H7A | 118.4 |
| C3—C2—C1 | 125.0 (2) |
| D—H···A | D—H | H···A | D···A | D—H···A |
| N1—H1B···O1i | 0.90 | 2.52 | 3.305 (3) | 146 |
| N1—H1C···N2ii | 0.90 | 2.34 | 3.123 (4) | 146 |
| Symmetry codes: (i) −x+2, −y, −z+1; (ii) −x+2, −y, −z. |
| D—H···A | D—H | H···A | D···A | D—H···A |
| N1—H1B···O1i | 0.90 | 2.52 | 3.305 (3) | 146 |
| N1—H1C···N2ii | 0.90 | 2.34 | 3.123 (4) | 146 |
| Symmetry codes: (i) −x+2, −y, −z+1; (ii) −x+2, −y, −z. |
The authors acnowledge financial support from the Ministry of Science and Technology of China (2005CCA03400, 2007 A A02Z160), the Chinese National Natural Science Foundation (20572060, 20472043), and the Department of Science and Technology of Guangdong Province (2005 A11601008).
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Benzaldehyde hydrazone and its analogues are important intermediates in heterocyclic chemistry, and they have been widely used for the synthesis of biologically active compounds such as [1,2,4]triazino[6,5-f]quinolines, pyrazolo[3,4-f]quinolines (Kawakami et al., 2000), 1,3-dithiol-2-ylidene derivatives (Moreno-Mañas et al., 2001), and oligo-RNAs with photocaged adenosine 2'-hydroxyls (Chaulk et al., 2007). Here we report the synthesis and crystal structure of a nitro-analogue: 2,4-dinitrobenzaldehyde hydrazone. The molecule of the title compound (Fig. 1) contains a benzene ring, a hydrazone chain and two nitryl groups. Most of the bond lengths and angles are within normal ranges (Allen et al., 1987). Because of the pi-pi conjugation and two nitryl groups electron withdrawing effect, the distance of C=N bond (1.282 (3) Å) is obviously shorter than that of the normal range (1.34–1.38 Å). The molecule is essentially planar, with a dihedral angle of 8.27° between the hydrazone group and the benzene ring. In the crystal structure, the molecules are linked by intermolecular N—H···O and N—H···N hydrogen bonds (Table 1, Fig. 2), which seem to be effective in the stabilization of the structure.