organic compounds
4,6-Dinitropyrogallol
aFachrichtung Chemie, Universität des Saarlandes, Postfach 151150, D-66041 Saarbrücken, Germany
*Correspondence e-mail: hegetschweiler@mx.uni-saarland.de
In the title molecule, C6H4N2O7, the two nitro groups are tilted with respect to the aromatic ring by 11.2 (1) and 10.9 (1)°. All three hydroxy groups are involved in the formation of bifurcated intra- and intermolecular O—H⋯O hydrogen bonds. The crystal packing exhibits short O⋯O distances of 2.823 (2) Å between two O atoms of the nitro groups.
Related literature
The synthesis of the title compound has recently been reported by Merten et al. (2012). The importance of hydrogen bonding, π stacking and donor–acceptor interactions in solid-state structures and in solution has been reviewed by Schneider (2009). The of dinitrophloroglucinol, a constitutional isomer of the title compound, has been described by Schweitzer et al. (2008). H atoms were treated as recommended by Müller et al. (2006).
Experimental
Crystal data
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Data collection
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Refinement
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Data collection: IPDS Software (Stoe & Cie, 1997); cell IPDS Software; data reduction: IPDS Software; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2011); software used to prepare material for publication: SHELXL97.
Supporting information
10.1107/S1600536812004771/cv5241sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536812004771/cv5241Isup2.hkl
Supporting information file. DOI: 10.1107/S1600536812004771/cv5241Isup3.cml
The title compound has been prepared by nitration of pyrogallol-triacetate. 1H NMR ([D6]acetone): δ (p.p.m.) = 8.51. 13C NMR ([D6]acetone): δ (p.p.m.) = 114.4, 128.7, 136.6, 148.8. Elemental analysis calculated for C6H4N2O7 (%): C 33.35, H 1.87, N 12.96; found (%): C 33.19, H 2.24, N 12.83. Single crystals were obtained directly from the reaction mixture at 278 K.
All non-hydrogen atoms were refined using anisotropic displacement parameters. H atoms were treated as recommended by Müller et al. (2006). A riding model was used for the C-bonded H5. The positional parameters of the O-bonded H1O, H2O and H3O were refined using isotropic displacement parameters which were set to 1.5Ueq of the pivot atom. In addition, a restraint of 0.84 Å was used for the O—H distances.
Data collection: IPDS Software (Stoe & Cie, 1997); cell
IPDS Software (Stoe & Cie, 1997); data reduction: IPDS Software (Stoe & Cie, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2011); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).Fig. 1. Molecular structure of the title compound. Displacement ellipsoids are drawn at the 50% probability level. | |
Fig. 2. Section of the hydrogen bonding network, showing bifurcated hydrogen bonds for all three hydroxy groups (displacement ellipsoids are drawn at the 50% probability level). |
C6H4N2O7 | Z = 4 |
Mr = 216.11 | F(000) = 440 |
Monoclinic, P21/c | Dx = 1.898 Mg m−3 |
a = 6.7612 (14) Å | Mo Kα radiation, λ = 0.71073 Å |
b = 10.878 (2) Å | µ = 0.18 mm−1 |
c = 10.297 (2) Å | T = 200 K |
β = 92.75 (3)° | Prism, light brown |
V = 756.5 (3) Å3 | 0.60 × 0.22 × 0.20 mm |
Stoe IPDS image plate diffractometer | 1326 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.059 |
Graphite monochromator | θmax = 26.0°, θmin = 2.7° |
ϕ scans | h = −8→8 |
5824 measured reflections | k = −13→13 |
1488 independent reflections | l = −12→12 |
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)] = 0.031 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.089 | w = 1/[σ2(Fo2) + (0.0484P)2 + 0.1574P] where P = (Fo2 + 2Fc2)/3 |
S = 1.06 | (Δ/σ)max < 0.001 |
1488 reflections | Δρmax = 0.31 e Å−3 |
146 parameters | Δρmin = −0.23 e Å−3 |
3 restraints | Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.093 (9) |
C6H4N2O7 | V = 756.5 (3) Å3 |
Mr = 216.11 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 6.7612 (14) Å | µ = 0.18 mm−1 |
b = 10.878 (2) Å | T = 200 K |
c = 10.297 (2) Å | 0.60 × 0.22 × 0.20 mm |
β = 92.75 (3)° |
Stoe IPDS image plate diffractometer | 1326 reflections with I > 2σ(I) |
5824 measured reflections | Rint = 0.059 |
1488 independent reflections |
R[F2 > 2σ(F2)] = 0.031 | 3 restraints |
wR(F2) = 0.089 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.06 | Δρmax = 0.31 e Å−3 |
1488 reflections | Δρmin = −0.23 e Å−3 |
146 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 | ||
C5 | 0.03683 (18) | 0.22251 (11) | 0.46470 (11) | 0.0173 (3) | |
H5 | 0.0181 | 0.1542 | 0.5203 | 0.021* | |
C2 | 0.09313 (18) | 0.42549 (12) | 0.30137 (11) | 0.0176 (3) | |
C6 | −0.10033 (17) | 0.31771 (12) | 0.45731 (11) | 0.0166 (3) | |
C1 | −0.07860 (17) | 0.42018 (11) | 0.37270 (11) | 0.0168 (3) | |
C4 | 0.20152 (17) | 0.22875 (11) | 0.38968 (11) | 0.0167 (3) | |
C3 | 0.23403 (17) | 0.33087 (12) | 0.30757 (11) | 0.0176 (3) | |
O2 | 0.11938 (14) | 0.52556 (9) | 0.22378 (9) | 0.0253 (3) | |
H2O | 0.235 (2) | 0.5179 (17) | 0.1964 (17) | 0.038* | |
O1 | −0.20607 (13) | 0.51466 (9) | 0.35774 (9) | 0.0228 (3) | |
H1O | −0.310 (2) | 0.4983 (17) | 0.3996 (17) | 0.034* | |
O3 | 0.38713 (14) | 0.34789 (10) | 0.23055 (10) | 0.0265 (3) | |
H3O | 0.467 (3) | 0.2905 (15) | 0.2362 (18) | 0.040* | |
N4 | 0.34037 (15) | 0.12578 (10) | 0.39485 (10) | 0.0184 (3) | |
N6 | −0.26572 (15) | 0.31109 (10) | 0.54231 (10) | 0.0195 (3) | |
O4 | 0.50228 (13) | 0.14010 (9) | 0.34200 (9) | 0.0250 (3) | |
O5 | 0.29368 (14) | 0.03088 (9) | 0.44938 (9) | 0.0259 (3) | |
O6 | −0.40392 (14) | 0.38686 (10) | 0.52605 (9) | 0.0288 (3) | |
O7 | −0.26491 (15) | 0.23213 (9) | 0.62784 (10) | 0.0289 (3) |
U11 | U22 | U33 | U12 | U13 | U23 | |
C5 | 0.0202 (6) | 0.0161 (6) | 0.0156 (5) | −0.0017 (5) | 0.0016 (4) | −0.0004 (5) |
C2 | 0.0208 (6) | 0.0168 (6) | 0.0152 (6) | −0.0010 (5) | 0.0011 (4) | 0.0022 (4) |
C6 | 0.0159 (6) | 0.0189 (6) | 0.0154 (6) | −0.0021 (5) | 0.0029 (4) | −0.0024 (4) |
C1 | 0.0179 (6) | 0.0171 (6) | 0.0151 (6) | 0.0020 (5) | −0.0010 (4) | −0.0027 (4) |
C4 | 0.0189 (6) | 0.0150 (6) | 0.0162 (6) | 0.0017 (4) | 0.0007 (5) | −0.0014 (4) |
C3 | 0.0165 (6) | 0.0208 (6) | 0.0158 (6) | −0.0009 (5) | 0.0025 (4) | −0.0013 (5) |
O2 | 0.0246 (5) | 0.0238 (5) | 0.0283 (5) | 0.0039 (4) | 0.0084 (4) | 0.0113 (4) |
O1 | 0.0209 (5) | 0.0231 (5) | 0.0247 (5) | 0.0065 (4) | 0.0048 (4) | 0.0036 (4) |
O3 | 0.0227 (5) | 0.0280 (6) | 0.0300 (5) | 0.0065 (4) | 0.0135 (4) | 0.0090 (4) |
N4 | 0.0199 (5) | 0.0191 (6) | 0.0163 (5) | 0.0019 (4) | 0.0011 (4) | −0.0012 (4) |
N6 | 0.0189 (5) | 0.0196 (6) | 0.0204 (5) | −0.0016 (4) | 0.0041 (4) | −0.0027 (4) |
O4 | 0.0208 (5) | 0.0265 (5) | 0.0284 (5) | 0.0056 (4) | 0.0084 (4) | 0.0003 (4) |
O5 | 0.0306 (5) | 0.0186 (5) | 0.0288 (5) | 0.0030 (4) | 0.0040 (4) | 0.0062 (4) |
O6 | 0.0214 (5) | 0.0345 (6) | 0.0314 (5) | 0.0085 (4) | 0.0091 (4) | 0.0023 (4) |
O7 | 0.0319 (5) | 0.0252 (5) | 0.0310 (5) | 0.0009 (4) | 0.0155 (4) | 0.0071 (4) |
C5—C4 | 1.3870 (17) | C4—N4 | 1.4609 (16) |
C5—C6 | 1.3898 (17) | C3—O3 | 1.3467 (15) |
C5—H5 | 0.9500 | O2—H2O | 0.846 (14) |
C2—O2 | 1.3669 (15) | O1—H1O | 0.859 (15) |
C2—C3 | 1.4019 (18) | O3—H3O | 0.827 (15) |
C2—C1 | 1.4046 (17) | N4—O5 | 1.2237 (15) |
C6—C1 | 1.4267 (17) | N4—O4 | 1.2554 (14) |
C6—N6 | 1.4545 (15) | N6—O7 | 1.2301 (15) |
C1—O1 | 1.3454 (15) | N6—O6 | 1.2512 (15) |
C4—C3 | 1.4195 (18) | ||
C4—C5—C6 | 118.97 (11) | C5—C4—N4 | 118.28 (11) |
C4—C5—H5 | 120.5 | O3—C3—C2 | 114.34 (11) |
C6—C5—H5 | 120.5 | O3—C3—C4 | 127.14 (12) |
O2—C2—C3 | 120.29 (11) | C2—C3—C4 | 118.51 (11) |
O2—C2—C1 | 118.18 (11) | C2—O2—H2O | 105.3 (13) |
C3—C2—C1 | 121.53 (11) | C1—O1—H1O | 108.5 (13) |
C5—C6—C1 | 121.85 (11) | C3—O3—H3O | 111.9 (13) |
C5—C6—N6 | 117.42 (11) | O5—N4—O4 | 123.58 (11) |
C1—C6—N6 | 120.71 (11) | O5—N4—C4 | 118.95 (11) |
O1—C1—C2 | 116.73 (11) | O4—N4—C4 | 117.47 (10) |
O1—C1—C6 | 125.64 (11) | O7—N6—O6 | 122.24 (11) |
C2—C1—C6 | 117.61 (11) | O7—N6—C6 | 119.22 (11) |
C5—C4—C3 | 121.43 (11) | O6—N6—C6 | 118.54 (10) |
C4—C5—C6—C1 | 1.40 (18) | O2—C2—C3—C4 | 179.79 (11) |
C4—C5—C6—N6 | −176.90 (10) | C1—C2—C3—C4 | −0.88 (18) |
O2—C2—C1—O1 | 0.65 (16) | C5—C4—C3—O3 | 179.92 (11) |
C3—C2—C1—O1 | −178.70 (11) | N4—C4—C3—O3 | −1.37 (19) |
O2—C2—C1—C6 | −177.52 (10) | C5—C4—C3—C2 | −1.28 (18) |
C3—C2—C1—C6 | 3.13 (17) | N4—C4—C3—C2 | 177.43 (10) |
C5—C6—C1—O1 | 178.59 (11) | C5—C4—N4—O5 | 10.41 (16) |
N6—C6—C1—O1 | −3.17 (18) | C3—C4—N4—O5 | −168.34 (11) |
C5—C6—C1—C2 | −3.43 (17) | C5—C4—N4—O4 | −169.81 (10) |
N6—C6—C1—C2 | 174.81 (10) | C3—C4—N4—O4 | 11.44 (16) |
C6—C5—C4—C3 | 1.01 (18) | C5—C6—N6—O7 | 9.35 (16) |
C6—C5—C4—N4 | −177.72 (10) | C1—C6—N6—O7 | −168.96 (11) |
O2—C2—C3—O3 | −1.27 (17) | C5—C6—N6—O6 | −171.03 (10) |
C1—C2—C3—O3 | 178.07 (10) | C1—C6—N6—O6 | 10.65 (16) |
D—H···A | D—H | H···A | D···A | D—H···A |
O2—H2O···O3 | 0.85 (1) | 2.14 (2) | 2.6467 (14) | 118 (2) |
O2—H2O···O4i | 0.85 (1) | 2.27 (2) | 2.9531 (14) | 138 (2) |
O1—H1O···O6 | 0.86 (2) | 1.91 (2) | 2.6359 (15) | 141 (2) |
O1—H1O···O6ii | 0.86 (2) | 2.46 (2) | 3.1361 (15) | 137 (2) |
O3—H3O···O4 | 0.83 (2) | 1.97 (2) | 2.6357 (14) | 137 (2) |
O3—H3O···O7iii | 0.83 (2) | 2.19 (2) | 2.7658 (15) | 127 (2) |
Symmetry codes: (i) −x+1, y+1/2, −z+1/2; (ii) −x−1, −y+1, −z+1; (iii) x+1, −y+1/2, z−1/2. |
Experimental details
Crystal data | |
Chemical formula | C6H4N2O7 |
Mr | 216.11 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 200 |
a, b, c (Å) | 6.7612 (14), 10.878 (2), 10.297 (2) |
β (°) | 92.75 (3) |
V (Å3) | 756.5 (3) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.18 |
Crystal size (mm) | 0.60 × 0.22 × 0.20 |
Data collection | |
Diffractometer | Stoe IPDS image plate diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 5824, 1488, 1326 |
Rint | 0.059 |
(sin θ/λ)max (Å−1) | 0.617 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.031, 0.089, 1.06 |
No. of reflections | 1488 |
No. of parameters | 146 |
No. of restraints | 3 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.31, −0.23 |
Computer programs: IPDS Software (Stoe & Cie, 1997), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg, 2011).
D—H···A | D—H | H···A | D···A | D—H···A |
O2—H2O···O3 | 0.846 (14) | 2.138 (18) | 2.6467 (14) | 118.4 (15) |
O2—H2O···O4i | 0.846 (14) | 2.271 (16) | 2.9531 (14) | 137.9 (16) |
O1—H1O···O6 | 0.859 (15) | 1.910 (16) | 2.6359 (15) | 141.3 (17) |
O1—H1O···O6ii | 0.859 (15) | 2.457 (17) | 3.1361 (15) | 136.5 (16) |
O3—H3O···O4 | 0.827 (15) | 1.973 (17) | 2.6357 (14) | 136.6 (17) |
O3—H3O···O7iii | 0.827 (15) | 2.187 (17) | 2.7658 (15) | 127.2 (16) |
Symmetry codes: (i) −x+1, y+1/2, −z+1/2; (ii) −x−1, −y+1, −z+1; (iii) x+1, −y+1/2, z−1/2. |
Acknowledgements
The authors thank Dr Volker Huch (Universität des Saarlandes) for the collection of the data set.
References
Brandenburg, K. (2011). DIAMOND. Crystal Impact GbR, Bonn, Germany. Google Scholar
Merten, G. J., Neis, C., Stucky, S., Huch, V., Rentschler, E., Natter, H., Hempelmann, R., Stöwe, K. & Hegetschweiler, K. (2012). Eur. J. Inorg. Chem. pp. 31–35. Web of Science CSD CrossRef Google Scholar
Müller, P., Herbst-Irmer, R., Spek, A. L., Schneider, T. R. & Sawaya, M. R. (2006). Crystal Structure Refinement – A Crystallographer's Guide to SHELXL. Oxford University Press. Google Scholar
Schneider, H.-J. (2009). Angew. Chem. Int. Ed. 48, 3924–3977. Web of Science CrossRef CAS Google Scholar
Schweitzer, T., Taylor, D., Choppin, G., Neis, C. & Hegetschweiler, K. (2008). Z. Kristallogr. New Cryst. Struct. 223, 369–370. CAS Google Scholar
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As expected, the aromatic C6-ring is planar (the positions of the six C atoms deviate from the mean plane by 0.0025 (8)–0.0196 (8) Å). The C6-ring and the two nitro groups are also approximately coplanar, allowing significant π-delocalization. In the extended hydrogen bonding network all three phenolic hydroxy groups act as hydrogen donors and the nitro groups as hydrogen acceptors. The O atoms O1 and O6 of two neighbouring molecules form a planar, four-membered O1···O6···O1'···O6' ring with two bifurcated hydrogen bonds. Remarkably, the O6···O6' distance of 2.823 (2) Å (i.e. one of the diagonal of the corresponding parallelogram) is somewhat shorter than the sum of the van der Waals radii, although no direct hydrogen bond between these two atoms is operative. Some intermolecular C···C and C···O distances (C1···C1': 3.279 Å, C5···O2": 3.046 Å) are slightly shorter than the sum of the van der Waals radii and may be interpreted in terms of π-stacking or weak donor–acceptor interactions.