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The title mol­ecule, C9H10N4O3, consists of benzene and imidazole rings which are almost perpendicular to each other. A hydroxy­imino group is directly linked to the imidazole ring with a double C=N bond, which is the first example in this type of compound. The double bond may be a good location for the initiation of various reactions with a wide range of potential applications. In the crystal structure, there are [pi]-[pi] inter­actions between mol­ecules related by a centre of symmetry, with the imidazole and benzene rings almost completely overlapped. The mol­ecules are hydrogen bonded in each direction and form a three-dimensional hydrogen-bond network.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270107040978/sf3047sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270107040978/sf3047Isup2.hkl
Contains datablock I

CCDC reference: 669198

Comment top

Having attempted to synthesize a new Schiff base by the reaction of 3,4-diaminoglyoxime and 4-hydroxybenzaldehyde, we unexpectedly obtained mainly the title compound, (I), and its molecular structure was finally confirmed by single-crystal structure determination after conventional IR, NMR, MS and elemental analysis.

Compound (I) (Fig. 1) is a nitrone (Popov et al., 2004). It is well known that nitrones are typical examples of 1,3-dipoles easily participating in cycloaddition reaction with a wide variety of multiple-bond systems, to provide various heterocyclic five-membered ring systems (Coskun & Yilmaz, 2004). Besides their synthetic applications, nitrones have a wide spectrum of biological activity (Voinov et al., 2000). The cycloadducts of di- and triarylimidazoline 3-oxides with many dipolarophiles give bicyclic compounds with potentially interesting biological activity (Coskun et al., 2006). The derivatives of 2,5-dihydro-1H-imidazole-3-oxide are magnetic (Roschupkina et al., 2004). Furthermore, the oxidation of these compounds can yield stable nitroxyl radicals (Martin & Volodarskii, 1979). Nitroxyl radicals are normally used as spin carriers, due to their exceptional stability and ease of chemical modification (Li et al., 2004). Nitroxide radical ligands based on the pyrazole ring are of great interest in understanding the role of the hydrogen bond as a pathway for magnetic exchange (Catala et al., 2001). Molecule-based magnetic materials are becoming more and more interesting, because the combination of metal ions and organic radicals has often been used to construct assembled systems (Oshio et al., 2001). In the field of molecular magnetism, the synthesis and study of transition metal complexes incorporating organic free radicals is a major research aim (Kahn, 1993). Therefore, it is our belief that the novel structure of the title compound must bring about new findings in cycloaddition reactions and applications of nitrones. Work towards these aims is now in progress in our laboratory. We present here the results of our study of the molecular structure of (I) and a brief analysis of the molecular packing.

The molecule of (I) consists of a phenyl ring and an imidazole ring. The dihedral angle between the two ring planes is 87.9 (1)°. While the two rings are almost perpendicular, atoms O1, N3 and N4 are almost coplanar with the imidazole ring (to within 0.03 Å). In addition, the N4—C3 bond length is 1.286 (2) Å and the four atoms N4, C3, C2 and N1 are nearly coplanar (the maximum deviation from the least-squares plane is 0.03 Å), which shows that the N—OH group is directly linked to the imidazole ring with a CN double bond. In this respect, compound (I) is the first example in this family of compounds, confirmed by a search of the Cambridge Structural Database (Version?, 2006; Allen, 2002). The double bond may be a good location for the initiation of various reactions having wide-ranging potential applications.

In the title crystal, molecules are paired through ππ interactions (Desiraju, 1989). There are two noticeable cases (Fig. 2) involving both theimidazole and the phenyl rings. In the reference molecule and its equivalent related by a centre of symmetry (symmetry code: 1 − x, −y, −z), the distances between the imidazole rings and their centroids are 3.354 and 3.603 Å, respectively, which shows that the ring planes are almost completely overlapped. For the phenyl···phenyl interaction, involving the reference molecule and another related by a centre of symmetry (symmetry code: −x, −y, 1 − z), the corresponding data are 3.693 and 3.719 Å, respectively.

In the crystal structure, N—H···N, N—H···O and O—H···O hydrogen bonds (Table 3 and Fig 2) link the molecules to form a three-dimensional network.

Experimental top

4-Hydrobenzaldehyde (3 mmol) and p-toluenesulfonic acid (0.175 mmol) were added to a solution of 3,4-diaminoglyoxime (2.5 mmol) in anhydrous ethanol (30 ml) with stirring at 328 K. The resulting mixture was stirred for 2 h at this temperature, then filtered and washed twice with anhydrous ethanol (yield 0.4662 g, 84%; white solid). Colourless quadrate crystals of (I) suitable for X-ray single-crystal study were obtained by slow evaporation from dimethylsulfoxide at room temperature after 10 d. Elemental analysis (EA1110CHNO-S analyzer): calculated for C9H10N4O3: C 48.65, H 4.50, N 25.23%; found: C 48.16, H 4.68, N 24.73%. IR (FT–IR spectrometer with KBr pellets, ν, cm−1): 3325 (s), 3176 (s), 3015 (s), 1710 (s), 1689 (s), 1610 (m), 1514 (m), 1473 (m), 1385 (m), 1223 (s), 933 (m). 1H NMR (UNITYNOVA400 NMR spectrometer, DMSO as solvent, ambient temperature, δ, p.p.m.): 1.06 (s, 1H), 5.57 (s, 1H), 5.64 (s, 1H), 6.28 (s, 2H), 6.75–7.39 (m, 4H), 10.19 (s, 1H).

Computing details top

Data collection: CrystalClear (Rigaku/MSC, 1999); cell refinement: CrystalClear; data reduction: CrystalStructure (Rigaku/MSC, 2003); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and XP (Siemens, 1990); software used to prepare material for publication: SHELXL97.

Figures top
[Figure 1] Fig. 1. A view of the molecular structure of (I), showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level and H atoms are shown as small spheres of arbitrary radii.
[Figure 2] Fig. 2. A packing diagram for (I), viewed down the a axis.
(4Z)-4-Amino-2-(4-hydroxyphenyl)-1H-imidazol-5(2H)-one oxime 3-oxide top
Crystal data top
C9H10N4O3Z = 2
Mr = 222.21F(000) = 232
Triclinic, P1Dx = 1.512 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71070 Å
a = 6.6739 (11) ÅCell parameters from 1606 reflections
b = 7.5697 (16) Åθ = 3.4–25.3°
c = 10.899 (2) ŵ = 0.12 mm1
α = 85.036 (18)°T = 193 K
β = 75.039 (15)°Block, colourless
γ = 66.596 (11)°0.55 × 0.18 × 0.16 mm
V = 488.09 (17) Å3
Data collection top
Rigaku Mercury
diffractometer
1768 independent reflections
Radiation source: fine-focus sealed tube1469 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.025
Detector resolution: 7.31 pixels mm-1θmax = 25.4°, θmin = 3.4°
ω scansh = 86
Absorption correction: multi-scan
(Jacobson, 1998)
k = 99
Tmin = 0.927, Tmax = 0.981l = 1213
4751 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.046Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.108H-atom parameters constrained
S = 1.09 w = 1/[σ2(Fo2) + (0.0441P)2 + 0.2338P]
where P = (Fo2 + 2Fc2)/3
1768 reflections(Δ/σ)max < 0.001
148 parametersΔρmax = 0.21 e Å3
0 restraintsΔρmin = 0.21 e Å3
Crystal data top
C9H10N4O3γ = 66.596 (11)°
Mr = 222.21V = 488.09 (17) Å3
Triclinic, P1Z = 2
a = 6.6739 (11) ÅMo Kα radiation
b = 7.5697 (16) ŵ = 0.12 mm1
c = 10.899 (2) ÅT = 193 K
α = 85.036 (18)°0.55 × 0.18 × 0.16 mm
β = 75.039 (15)°
Data collection top
Rigaku Mercury
diffractometer
1768 independent reflections
Absorption correction: multi-scan
(Jacobson, 1998)
1469 reflections with I > 2σ(I)
Tmin = 0.927, Tmax = 0.981Rint = 0.025
4751 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0460 restraints
wR(F2) = 0.108H-atom parameters constrained
S = 1.09Δρmax = 0.21 e Å3
1768 reflectionsΔρmin = 0.21 e Å3
148 parameters
Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O10.2456 (2)0.46350 (18)0.13373 (12)0.0266 (3)
O20.8072 (2)0.33332 (19)0.14069 (14)0.0326 (4)
H20.93710.41680.13780.049*
O30.3049 (3)0.3475 (2)0.70012 (13)0.0383 (4)
H30.25310.39940.74230.057*
N10.4195 (3)0.0379 (2)0.18426 (16)0.0287 (4)
H1A0.40510.14750.20650.034*
N20.3539 (2)0.2737 (2)0.14515 (14)0.0221 (4)
N30.7165 (3)0.2593 (2)0.05181 (16)0.0278 (4)
H3A0.66920.38460.04140.033*
H3B0.86080.18650.02690.033*
N40.8202 (3)0.1529 (2)0.10520 (15)0.0253 (4)
C10.2318 (3)0.1486 (3)0.19970 (18)0.0234 (4)
H1B0.13040.15210.14530.028*
C20.5708 (3)0.1805 (3)0.10475 (17)0.0216 (4)
C30.6191 (3)0.0226 (3)0.13160 (17)0.0218 (4)
C40.0956 (3)0.2036 (3)0.33409 (18)0.0225 (4)
C50.1896 (3)0.2197 (3)0.4294 (2)0.0329 (5)
H50.34530.19630.41020.039*
C60.0600 (4)0.2696 (3)0.5526 (2)0.0355 (5)
H60.12570.28250.61720.043*
C70.1651 (3)0.3004 (3)0.58040 (18)0.0288 (5)
C80.2589 (4)0.2828 (4)0.4868 (2)0.0419 (6)
H80.41370.30280.50650.050*
C90.1298 (3)0.2362 (3)0.3638 (2)0.0364 (5)
H90.19710.22650.29910.044*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0242 (7)0.0172 (7)0.0305 (8)0.0023 (6)0.0031 (6)0.0012 (5)
O20.0263 (8)0.0168 (7)0.0476 (9)0.0049 (6)0.0043 (7)0.0047 (6)
O30.0465 (9)0.0417 (10)0.0284 (8)0.0287 (8)0.0100 (7)0.0092 (7)
N10.0214 (9)0.0195 (9)0.0396 (10)0.0081 (7)0.0026 (7)0.0013 (7)
N20.0200 (8)0.0190 (8)0.0224 (8)0.0047 (7)0.0018 (6)0.0004 (6)
N30.0188 (8)0.0214 (9)0.0380 (10)0.0060 (7)0.0023 (7)0.0043 (7)
N40.0234 (9)0.0198 (9)0.0278 (9)0.0064 (7)0.0020 (7)0.0022 (6)
C10.0200 (10)0.0212 (10)0.0275 (11)0.0080 (8)0.0031 (8)0.0008 (8)
C20.0195 (10)0.0230 (10)0.0193 (10)0.0064 (8)0.0027 (8)0.0001 (7)
C30.0210 (10)0.0235 (10)0.0183 (10)0.0081 (8)0.0012 (8)0.0003 (7)
C40.0216 (10)0.0179 (10)0.0249 (10)0.0067 (8)0.0020 (8)0.0005 (7)
C50.0216 (10)0.0425 (13)0.0313 (12)0.0116 (10)0.0017 (9)0.0020 (9)
C60.0347 (12)0.0429 (14)0.0290 (12)0.0154 (10)0.0066 (10)0.0024 (9)
C70.0358 (12)0.0231 (11)0.0245 (11)0.0154 (9)0.0046 (9)0.0019 (8)
C80.0261 (11)0.0604 (16)0.0393 (14)0.0228 (11)0.0061 (10)0.0130 (11)
C90.0254 (11)0.0520 (15)0.0322 (12)0.0164 (10)0.0021 (9)0.0095 (10)
Geometric parameters (Å, º) top
O1—N21.3388 (19)C1—C41.504 (3)
O2—N41.417 (2)C1—H1B1.0000
O2—H20.8400C2—C31.460 (3)
O3—C71.374 (2)C4—C91.377 (3)
O3—H30.8400C4—C51.380 (3)
N1—C31.353 (2)C5—C61.387 (3)
N1—C11.455 (2)C5—H50.9500
N1—H1A0.8800C6—C71.379 (3)
N2—C21.304 (2)C6—H60.9500
N2—C11.476 (2)C7—C81.368 (3)
N3—C21.321 (2)C8—C91.381 (3)
N3—H3A0.8800C8—H80.9500
N3—H3B0.8800C9—H90.9500
N4—C31.286 (2)
N4—O2—H2109.5N4—C3—N1130.36 (18)
C7—O3—H3109.5N4—C3—C2122.48 (17)
C3—N1—C1112.02 (16)N1—C3—C2107.15 (16)
C3—N1—H1A124.0C9—C4—C5118.73 (18)
C1—N1—H1A124.0C9—C4—C1119.01 (18)
C2—N2—O1124.45 (16)C5—C4—C1122.25 (17)
C2—N2—C1113.74 (16)C4—C5—C6120.94 (19)
O1—N2—C1121.72 (14)C4—C5—H5119.5
C2—N3—H3A120.0C6—C5—H5119.5
C2—N3—H3B120.0C7—C6—C5119.3 (2)
H3A—N3—H3B120.0C7—C6—H6120.3
C3—N4—O2108.09 (15)C5—C6—H6120.3
N1—C1—N299.90 (14)C8—C7—O3116.73 (19)
N1—C1—C4115.07 (16)C8—C7—C6120.07 (19)
N2—C1—C4113.29 (15)O3—C7—C6123.19 (19)
N1—C1—H1B109.4C7—C8—C9120.3 (2)
N2—C1—H1B109.4C7—C8—H8119.8
C4—C1—H1B109.4C9—C8—H8119.8
N2—C2—N3125.37 (18)C4—C9—C8120.6 (2)
N2—C2—C3107.14 (16)C4—C9—H9119.7
N3—C2—C3127.48 (17)C8—C9—H9119.7
C3—N1—C1—N21.1 (2)N2—C2—C3—N12.0 (2)
C3—N1—C1—C4120.54 (18)N3—C2—C3—N1179.10 (19)
C2—N2—C1—N10.3 (2)N1—C1—C4—C9119.6 (2)
O1—N2—C1—N1177.07 (14)N2—C1—C4—C9126.4 (2)
C2—N2—C1—C4123.17 (18)N1—C1—C4—C559.4 (2)
O1—N2—C1—C460.0 (2)N2—C1—C4—C554.6 (2)
O1—N2—C2—N33.0 (3)C9—C4—C5—C60.6 (3)
C1—N2—C2—N3179.72 (17)C1—C4—C5—C6179.63 (19)
O1—N2—C2—C3178.11 (15)C4—C5—C6—C71.1 (3)
C1—N2—C2—C31.4 (2)C5—C6—C7—C80.4 (3)
O2—N4—C3—N10.4 (3)C5—C6—C7—O3179.04 (19)
O2—N4—C3—C2178.79 (15)O3—C7—C8—C9179.9 (2)
C1—N1—C3—N4178.78 (19)C6—C7—C8—C90.7 (4)
C1—N1—C3—C22.0 (2)C5—C4—C9—C80.4 (3)
N2—C2—C3—N4178.62 (18)C1—C4—C9—C8178.6 (2)
N3—C2—C3—N40.2 (3)C7—C8—C9—C41.1 (4)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N3—H3B···N4i0.882.172.944 (2)146
N3—H3A···O1ii0.882.212.825 (2)127
N1—H1A···O3iii0.881.992.843 (2)163
O3—H3···O1iv0.841.802.598 (2)159
O2—H2···O1v0.841.882.6949 (19)163
Symmetry codes: (i) x+2, y, z; (ii) x+1, y+1, z; (iii) x, y, z+1; (iv) x, y+1, z+1; (v) x+1, y1, z.

Experimental details

Crystal data
Chemical formulaC9H10N4O3
Mr222.21
Crystal system, space groupTriclinic, P1
Temperature (K)193
a, b, c (Å)6.6739 (11), 7.5697 (16), 10.899 (2)
α, β, γ (°)85.036 (18), 75.039 (15), 66.596 (11)
V3)488.09 (17)
Z2
Radiation typeMo Kα
µ (mm1)0.12
Crystal size (mm)0.55 × 0.18 × 0.16
Data collection
DiffractometerRigaku Mercury
diffractometer
Absorption correctionMulti-scan
(Jacobson, 1998)
Tmin, Tmax0.927, 0.981
No. of measured, independent and
observed [I > 2σ(I)] reflections
4751, 1768, 1469
Rint0.025
(sin θ/λ)max1)0.602
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.046, 0.108, 1.09
No. of reflections1768
No. of parameters148
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.21, 0.21

Computer programs: CrystalClear (Rigaku/MSC, 1999), CrystalClear, CrystalStructure (Rigaku/MSC, 2003), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ORTEP-3 for Windows (Farrugia, 1997) and XP (Siemens, 1990), SHELXL97.

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N3—H3B···N4i0.882.172.944 (2)146.0
N3—H3A···O1ii0.882.212.825 (2)127.0
N1—H1A···O3iii0.881.992.843 (2)163.0
O3—H3···O1iv0.841.802.598 (2)159.1
O2—H2···O1v0.841.882.6949 (19)162.6
Symmetry codes: (i) x+2, y, z; (ii) x+1, y+1, z; (iii) x, y, z+1; (iv) x, y+1, z+1; (v) x+1, y1, z.
 

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