organic compounds
o-Benzoquinone dioxime
aDipartimento di Chimica I.F.M.,University of Turin, Via P. Giuria 7, 10125, Torino, Italy
*Correspondence e-mail: giuliana.gervasio@unito.it
The title compound, C6H6N2O2, was obtained as a product of an in vitro study of the metabolism of benzofuroxan. The molecule exhibits a amphi configuration of the oxime groups C=N—OH. One oxime group is involved in the formation of a strong intramolecular O—H⋯N hydrogen bond, while another links molecules into zigzag chains along the c axis via intermolecular O—H⋯N hydrogen bonds.
Related literature
For details of the synthesis, see: Grosa et al. (2004). For a related structure, see: Mégnamisi-Bélombé & Endres (1985).
Experimental
Crystal data
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Refinement
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Data collection: SMART (Bruker, 2007); cell SAINT (Bruker, 2007); data reduction: SAINT; 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
https://doi.org/10.1107/S1600536810039619/cv2766sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810039619/cv2766Isup2.hkl
A very small and poorly diffracting crystal has been used; it was not possible to obtain a better crystal because it is a product of a metabolism. C-bound H atoms were placed in geometrically idealized positions (C—H = 0.93 Å), and refined as riding, with Uiso(H) = 1.2Ueq(C). Two O-bound H atoms were located on a difference map and refined isotropically. A restraint has been imposed on the planarity of the hexagonal ring. In the absence of any significant anomalous scatterers in the molecule, 368 Friedel pairs were merged before the final refinement.
The title compound, o-benzoquinone dioxime, has been obtained according to Grosa et al. (2004). In the C1—C6 ring the C3-C4 and C5-C6 bond distances correspond to formal double bonds (1.336 (5) Å av.). Also the C1-N1 and C2-N2 distances agree with a double bond character (1.304 (5) Å av.). Noteworthy is the presence of a strong intramolecular hydrogen bond O2-H2···N2 that probably stabilize the syn form of the dioxime. A further intermolecular hydrogen bond O1-H1..N2 forms chains of molecules. O-benzoquinone dioxime is known as an excellent ligand which forms bis-chelated transition metal complexes especially with the dipositive metal ions of the Ni triad (cf. Mégnamisi-Bélombé & Endres, 1985).
For details of the synthesis, see: Grosa et al. (2004). For a related structure, see: Mégnamisi-Bélombé & Endres (1985).
Data collection: SMART (Bruker, 2007); cell
SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); 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).Fig. 1. The molecular structure of trhe title compound showing the atomic numbering and 50% of probability displacements ellipsoids. |
C6H6N2O2 | Dx = 1.497 Mg m−3 |
Mr = 138.13 | Mo Kα radiation, λ = 0.71073 Å |
Orthorhombic, Pca21 | Cell parameters from 500 reflections |
a = 15.009 (5) Å | θ = 2.7–23.3° |
b = 3.8181 (13) Å | µ = 0.12 mm−1 |
c = 10.694 (3) Å | T = 293 K |
V = 612.8 (4) Å3 | Prism, orange |
Z = 4 | 0.24 × 0.12 × 0.04 mm |
F(000) = 288 |
Siemens–Bruker APEX diffractometer | 418 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.055 |
Graphite monochromator | θmax = 23.3°, θmin = 2.7° |
φ scans | h = −16→16 |
Absorption correction: multi-scan (Blessing, 1995) | k = −4→3 |
Tmin = 0.856, Tmax = 1.000 | l = −11→11 |
2330 measured reflections | 11 standard reflections every 60 min |
468 independent reflections | intensity decay: none |
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)] = 0.034 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.082 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.01 | w = 1/[σ2(Fo2) + (0.0605P)2] where P = (Fo2 + 2Fc2)/3 |
468 reflections | (Δ/σ)max < 0.001 |
99 parameters | Δρmax = 0.19 e Å−3 |
1 restraint | Δρmin = −0.13 e Å−3 |
C6H6N2O2 | V = 612.8 (4) Å3 |
Mr = 138.13 | Z = 4 |
Orthorhombic, Pca21 | Mo Kα radiation |
a = 15.009 (5) Å | µ = 0.12 mm−1 |
b = 3.8181 (13) Å | T = 293 K |
c = 10.694 (3) Å | 0.24 × 0.12 × 0.04 mm |
Siemens–Bruker APEX diffractometer | 418 reflections with I > 2σ(I) |
Absorption correction: multi-scan (Blessing, 1995) | Rint = 0.055 |
Tmin = 0.856, Tmax = 1.000 | θmax = 23.3° |
2330 measured reflections | 11 standard reflections every 60 min |
468 independent reflections | intensity decay: none |
R[F2 > 2σ(F2)] = 0.034 | 1 restraint |
wR(F2) = 0.082 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.01 | Δρmax = 0.19 e Å−3 |
468 reflections | Δρmin = −0.13 e Å−3 |
99 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 | ||
C1 | 0.6109 (3) | 0.3317 (8) | 0.4796 (3) | 0.0377 (8) | |
C2 | 0.5481 (2) | 0.2457 (9) | 0.5795 (3) | 0.0377 (8) | |
C3 | 0.5843 (3) | 0.0751 (9) | 0.6896 (3) | 0.0479 (10) | |
H3A | 0.5461 | 0.0119 | 0.7543 | 0.057* | |
C4 | 0.6706 (3) | 0.0072 (9) | 0.6998 (3) | 0.0520 (12) | |
H4A | 0.6919 | −0.1043 | 0.7711 | 0.062* | |
C5 | 0.7312 (3) | 0.1027 (10) | 0.6031 (3) | 0.0532 (10) | |
H5A | 0.7916 | 0.0552 | 0.6128 | 0.064* | |
C6 | 0.7028 (3) | 0.2599 (9) | 0.4981 (3) | 0.0461 (9) | |
H6A | 0.7437 | 0.3225 | 0.4368 | 0.055* | |
N1 | 0.5761 (2) | 0.4735 (7) | 0.3794 (3) | 0.0426 (8) | |
N2 | 0.4629 (2) | 0.3068 (8) | 0.5828 (3) | 0.0489 (8) | |
O1 | 0.6388 (2) | 0.5573 (8) | 0.2905 (2) | 0.0561 (8) | |
H1 | 0.603 (4) | 0.638 (17) | 0.236 (6) | 0.11 (2)* | |
O2 | 0.4235 (2) | 0.4598 (7) | 0.4801 (2) | 0.0584 (9) | |
H2 | 0.477 (5) | 0.541 (17) | 0.422 (6) | 0.13 (2)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.045 (2) | 0.0412 (18) | 0.0267 (15) | −0.0013 (15) | −0.0039 (15) | −0.0047 (13) |
C2 | 0.043 (2) | 0.0426 (19) | 0.0278 (15) | −0.0044 (16) | 0.0022 (16) | −0.0053 (14) |
C3 | 0.067 (3) | 0.046 (2) | 0.0306 (17) | −0.0030 (17) | 0.0005 (18) | −0.0007 (18) |
C4 | 0.072 (3) | 0.050 (2) | 0.035 (2) | 0.004 (2) | −0.018 (2) | 0.0031 (14) |
C5 | 0.054 (3) | 0.055 (2) | 0.050 (2) | 0.0067 (19) | −0.012 (2) | −0.0059 (17) |
C6 | 0.047 (2) | 0.053 (2) | 0.0382 (18) | 0.0039 (18) | −0.0018 (17) | −0.0051 (17) |
N1 | 0.041 (2) | 0.0576 (19) | 0.0294 (14) | −0.0035 (13) | 0.0044 (16) | −0.0011 (12) |
N2 | 0.051 (2) | 0.0646 (18) | 0.0306 (14) | 0.0003 (17) | 0.0034 (15) | −0.0015 (16) |
O1 | 0.0470 (18) | 0.091 (2) | 0.0303 (12) | −0.0017 (14) | 0.0032 (14) | 0.0104 (13) |
O2 | 0.046 (2) | 0.090 (2) | 0.0393 (14) | 0.0042 (14) | −0.0021 (14) | 0.0018 (13) |
C1—N1 | 1.309 (5) | C4—H4A | 0.9300 |
C1—C6 | 1.420 (5) | C5—C6 | 1.342 (5) |
C1—C2 | 1.462 (5) | C5—H5A | 0.9300 |
C2—N2 | 1.299 (4) | C6—H6A | 0.9300 |
C2—C3 | 1.450 (5) | N1—O1 | 1.375 (4) |
C3—C4 | 1.326 (6) | N2—O2 | 1.377 (4) |
C3—H3A | 0.9300 | O1—H1 | 0.85 (7) |
C4—C5 | 1.425 (6) | O2—H2 | 1.06 (8) |
N1—C1—C6 | 125.5 (3) | C5—C4—H4A | 119.5 |
N1—C1—C2 | 115.8 (3) | C6—C5—C4 | 121.2 (4) |
C6—C1—C2 | 118.7 (3) | C6—C5—H5A | 119.4 |
N2—C2—C3 | 115.3 (3) | C4—C5—H5A | 119.4 |
N2—C2—C1 | 127.8 (3) | C5—C6—C1 | 120.8 (4) |
C3—C2—C1 | 116.9 (3) | C5—C6—H6A | 119.6 |
C4—C3—C2 | 121.4 (4) | C1—C6—H6A | 119.6 |
C4—C3—H3A | 119.3 | C1—N1—O1 | 112.9 (3) |
C2—C3—H3A | 119.3 | C2—N2—O2 | 118.5 (3) |
C3—C4—C5 | 120.9 (3) | N1—O1—H1 | 97 (4) |
C3—C4—H4A | 119.5 | N2—O2—H2 | 105 (4) |
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···N2i | 0.85 (7) | 1.92 (7) | 2.745 (4) | 162 (6) |
O2—H2···N1 | 1.06 (8) | 1.57 (8) | 2.532 (4) | 147 (6) |
Symmetry code: (i) −x+1, −y+1, z−1/2. |
Experimental details
Crystal data | |
Chemical formula | C6H6N2O2 |
Mr | 138.13 |
Crystal system, space group | Orthorhombic, Pca21 |
Temperature (K) | 293 |
a, b, c (Å) | 15.009 (5), 3.8181 (13), 10.694 (3) |
V (Å3) | 612.8 (4) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.12 |
Crystal size (mm) | 0.24 × 0.12 × 0.04 |
Data collection | |
Diffractometer | Siemens–Bruker APEX |
Absorption correction | Multi-scan (Blessing, 1995) |
Tmin, Tmax | 0.856, 1.000 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 2330, 468, 418 |
Rint | 0.055 |
θmax (°) | 23.3 |
(sin θ/λ)max (Å−1) | 0.556 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.034, 0.082, 1.01 |
No. of reflections | 468 |
No. of parameters | 99 |
No. of restraints | 1 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.19, −0.13 |
Computer programs: SMART (Bruker, 2007), SAINT (Bruker, 2007), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···N2i | 0.85 (7) | 1.92 (7) | 2.745 (4) | 162 (6) |
O2—H2···N1 | 1.06 (8) | 1.57 (8) | 2.532 (4) | 147 (6) |
Symmetry code: (i) −x+1, −y+1, z−1/2. |
Acknowledgements
We thank Professor A. Gasco for supplying crystals of the title compound.
References
Blessing, R. H. (1995). Acta Cryst. A51, 33–38. CrossRef CAS Web of Science IUCr Journals Google Scholar
Bruker (2007). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Grosa, G., Galli, U., Rolando, B., Fruttero, R., Gervasio, G. & Gasco, A. (2004). Xenobiotica, 34, 345–352. Web of Science CrossRef PubMed CAS Google Scholar
Mégnamisi-Bélombé, M. & Endres, H. (1985). Acta Cryst. C41, 513–515. CSD CrossRef Web of Science IUCr Journals Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122. Web of Science CrossRef CAS IUCr Journals Google Scholar
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The title compound, o-benzoquinone dioxime, has been obtained according to Grosa et al. (2004). In the C1—C6 ring the C3-C4 and C5-C6 bond distances correspond to formal double bonds (1.336 (5) Å av.). Also the C1-N1 and C2-N2 distances agree with a double bond character (1.304 (5) Å av.). Noteworthy is the presence of a strong intramolecular hydrogen bond O2-H2···N2 that probably stabilize the syn form of the dioxime. A further intermolecular hydrogen bond O1-H1..N2 forms chains of molecules. O-benzoquinone dioxime is known as an excellent ligand which forms bis-chelated transition metal complexes especially with the dipositive metal ions of the Ni triad (cf. Mégnamisi-Bélombé & Endres, 1985).