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The crystal structure of the title compound, C14H12N4O3, shows that the stereochemistry about the N=N double bond of the N=N—N(H) moiety is trans. The whole mol­ecule is almost planar (r.m.s. deviation = 0.0654 Å), the interplanar angle between the phenyl rings being 0.7 (1)° and the largest interplanar angle being that between the phenyl ring and the nitro group of the 4-nitro­phenyl substituent [11.5 (2)°]. Intermolecular N—H...O interactions between mol­ecules related by translation give rise to chains along the [110] and [1\overline 10] directions, and these chains are held together by N...O π–π interactions. An unequal distribution of the double-bond character among the N atoms suggests a delocalization of π electrons over the diazo­amine group and the adjacent aryl substituents.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270104004822/fr1466sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270104004822/fr1466Isup2.hkl
Contains datablock I

CCDC reference: 241221

Comment top

Numerous examples of free 1,3-disubstituted triazenes, RN=N—N(H)R (R = aryl or alkyl), characterized by X-ray diffraction studies have confirmed a trans stereochemistry about the N=N double bond (Moore & Robinson, 1986). On the other hand, free 1,3-diaryltriazenes show that the N=N—N(H) moiety is able to support intermolecular interactions by hydrogen bonding with polarizable atoms of the terminal aryl rings, giving rise to infinite chains that are commonly associated by weak interactions. This work forms part of a study of intermolecular hydrogen-bonding interactions in the solid state of asymmetric disubstituted 1,3-diaryltriazenes having π acid groups on the terminal aryl rings.

The molecular structure of (I) is shown in Fig. 1 and selected geometric parameters are given in Table 1. A typical feature of free diaryltriazenes is the delocalization of the π electrons on the triazene group, extending to the terminal aryl substituents. This observation is supported by the deviations from normal N—N and Car—N bond lengths. The N11=N12 bond [1.267 (2) Å] is longer than the characteristic value for a double bond (1.236 Å), whereas the N12—N13 bond [1.322 (2) Å] is shorter than the characteristic value for a single bond (1.404 Å; Allen et al., 1987; Teatum et al., 1960). Both the C21—N13 [1.392 (3) Å] and the C11—N11 bonds [1.416 (3) Å] are shorter than expected for N—Caryl single bonds (secondary amines, NHR2, R = Csp2; 1.452 Å; Orpen et al., 1989). These values are in good agreement with those found in the related compounds 1,3-bis(3-nitrophenyl)- triazene [N=N = 1.261 (2) Å and N—N = 1.326 (2) Å; Zhang et al., 1999] and 1,3-bis(4-acetylphenyl)triazene [N=N = 1.267 (4) Å and N—N = 1.329 (3) Å; Walton et al., 1991].

The crystal structure contains molecules related by translation, which form chains along the [110] and [1–10] directions via N—H···O hydrogen bonds [N13···O1i = 2.881 (3) Å and N13—H3···O1i = 159 (2)°; symmetry code: (i) 1/2 + x, −1/2 + y, z]. These chains are held together by N···O ππ interactions [N1···O11ii = 3.317 (3) Å and O11···N1iii = 3.317 (3) Å; symmetry codes: (ii) 3/2 − x, 1/2 + y, 3/2 − z; (iii) 3/2 − x, −1/2 + y, 3/2 − z; Fig. 2]. On the other hand, these weak intermolecular N···O ππ contacts hinder the coplanarity of the O11/N1/O12 nitro group with the C11–C16 phenyl ring [the interplanar angle is 11.5 (2)°]. The phenyl rings are planar within experimental error (r.m.s. 0.0032 Å) and make an interplanar angle of 0.7 (1)°, indicating that the whole molecule is almost planar.

Experimental top

4-Nitroaniline (2.76 g, 20.0 mmol) was dissolved in a 50% aqueous solution of HCl (40 ml) and cooled to 270–273 K. A sodium nitrite solution (1.37 g, 20.0 mmol) in water (20 ml) was added slowly with continuous stirring. A solution of 4-acetylaniline (2.70 g, 20.0 mmol) in glacial acetic acid (40 ml) was added slowly to the reaction mixture. Stirring was continued for 2 h (at a temperature below 268 K). The resulting mixture was neutralized with a 10% aqueous solution of NaHCO3. The orange crude product was isolated by filtration and dried over P2O5 under vacuum. The product was recrystallized from a tetrahydrofuran/n-hexane mixture (1:1). Orange column-shaped crystals of (I), suitable for X-ray analysis, were obtained by slow evaporation of the solvent mixture (yield 5.12 g, 90%; m.p. 433–434 K).

Refinement top

H atoms of the phenyl rings and of the methyl group were positioned geometrically (C—H = 0.93 Å for Csp2 and 0.96 Å for Csp3 atoms) and treated as riding on their respective C atoms, with Uiso(H) values set at 1.2Ueq(Csp2) and 1.5Ueq(Csp3). The positional parameters of atom H3 were obtained from a difference map and refined with an isotropic displacement parameter. The methyl group was refined as a rigid group, with the rotation around the C2—C3 bond as a free variable. The nitro O atoms and the acetyl O atom have elongated displacement ellipsoids (Fig. 1). Split peaks for these atoms were not observed and consequently a disorder model was not used in the refinement.

Computing details top

Data collection: CAD-4 EXPRESS (Enraf Nonius, 1994); cell refinement: CAD-4 EXPRESS (Enraf Nonius, 1994); data reduction: XCAD4 (Harms & Wocadlo, 1995); 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), DIAMOND (Brandenburg, 1996); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top
[Figure 1] Fig. 1. The molecular structure of (I), with 50% probability ellipsoids for non-H atoms.
[Figure 2] Fig. 2. The unit cell of (I) in a view inclined towards [010] and [001]. The N—H···O hydrogen bonds and transmolecular interactions N···O ππ interactions are shown as thin lines. [Symmetry codes: (i) 1/2 + x, −1/2 + y, z; (ii) 3/2 − x, 1/2 + y, 3/2 − z; (iii) 3/2 − x, −1/2 + y, 3/2 − z.]
(I) top
Crystal data top
C14H12N4O3F(000) = 1184
Mr = 284.28Dx = 1.388 Mg m3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2ycCell parameters from 25 reflections
a = 14.357 (6) Åθ = 10.2–24.0°
b = 7.1964 (13) ŵ = 0.10 mm1
c = 26.779 (5) ÅT = 293 K
β = 100.35 (4)°Prism, orange
V = 2721.7 (13) Å30.40 × 0.40 × 0.25 mm
Z = 8
Data collection top
Enraf-Nonius CAD-4
diffractometer
Rint = 0.015
Radiation source: fine-focus sealed tubeθmax = 28.0°, θmin = 3.0°
Graphite monochromatorh = 1818
ω scansk = 09
3468 measured reflectionsl = 135
3266 independent reflections3 standard reflections every 60 min
1809 reflections with I > 2σ(I) intensity decay: <1%
Refinement top
Refinement on F20 restraints
Least-squares matrix: fullH atoms treated by a mixture of independent and constrained refinement
R[F2 > 2σ(F2)] = 0.052
wR(F2) = 0.142(Δ/σ)max < 0.001
S = 1.01Δρmax = 0.14 e Å3
3266 reflectionsΔρmin = 0.14 e Å3
195 parameters
Crystal data top
C14H12N4O3V = 2721.7 (13) Å3
Mr = 284.28Z = 8
Monoclinic, C2/cMo Kα radiation
a = 14.357 (6) ŵ = 0.10 mm1
b = 7.1964 (13) ÅT = 293 K
c = 26.779 (5) Å0.40 × 0.40 × 0.25 mm
β = 100.35 (4)°
Data collection top
Enraf-Nonius CAD-4
diffractometer
Rint = 0.015
3468 measured reflections3 standard reflections every 60 min
3266 independent reflections intensity decay: <1%
1809 reflections with I > 2σ(I)
Refinement top
R[F2 > 2σ(F2)] = 0.0520 restraints
wR(F2) = 0.142H atoms treated by a mixture of independent and constrained refinement
S = 1.01Δρmax = 0.14 e Å3
3266 reflectionsΔρmin = 0.14 e Å3
195 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O10.01964 (11)0.6804 (2)0.39769 (6)0.0771 (5)
O110.76728 (14)0.2796 (3)0.75888 (7)0.1064 (7)
O120.63806 (14)0.3986 (3)0.77367 (6)0.0976 (7)
N10.68538 (16)0.3291 (3)0.74482 (8)0.0761 (6)
N110.52677 (12)0.2366 (3)0.53903 (6)0.0566 (5)
N120.44704 (11)0.3132 (2)0.52462 (6)0.0532 (4)
N130.41564 (12)0.2878 (3)0.47558 (7)0.0567 (5)
C20.07135 (14)0.5958 (3)0.37417 (8)0.0530 (5)
C30.04492 (16)0.5816 (4)0.31830 (8)0.0720 (7)
H3A0.01760.63090.30760.108*
H3B0.04590.45350.30840.108*
H3C0.08910.65080.30270.108*
C110.56121 (14)0.2645 (3)0.59145 (7)0.0515 (5)
C120.51637 (15)0.3705 (3)0.62349 (8)0.0607 (6)
H120.45890.42810.6110.073*
C130.55709 (16)0.3898 (3)0.67364 (8)0.0643 (6)
H130.52730.45980.69540.077*
C140.64239 (15)0.3047 (3)0.69143 (8)0.0586 (6)
C150.68790 (16)0.1988 (3)0.66067 (8)0.0626 (6)
H150.74530.14160.67350.075*
C160.64685 (14)0.1788 (3)0.61037 (8)0.0578 (6)
H160.67670.10750.5890.069*
C210.32960 (13)0.3626 (3)0.45181 (7)0.0468 (5)
C220.30022 (14)0.3275 (3)0.40068 (7)0.0510 (5)
H220.33690.2540.38320.061*
C230.21645 (13)0.4016 (3)0.37578 (7)0.0506 (5)
H230.19720.3780.34130.061*
C240.15986 (12)0.5111 (3)0.40088 (7)0.0463 (5)
C250.18991 (14)0.5430 (3)0.45256 (7)0.0518 (5)
H250.15240.6140.47020.062*
C260.27378 (13)0.4716 (3)0.47791 (7)0.0526 (5)
H260.29330.49570.51230.063*
H30.4492 (16)0.231 (3)0.4581 (8)0.064 (7)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0617 (10)0.0969 (13)0.0741 (11)0.0288 (9)0.0160 (8)0.0031 (9)
O110.0804 (13)0.154 (2)0.0741 (12)0.0106 (14)0.0147 (10)0.0004 (13)
O120.0881 (13)0.1498 (19)0.0564 (10)0.0121 (13)0.0170 (10)0.0025 (11)
N10.0706 (14)0.0978 (17)0.0571 (12)0.0151 (12)0.0042 (11)0.0136 (12)
N110.0468 (10)0.0631 (11)0.0567 (10)0.0047 (9)0.0012 (8)0.0034 (9)
N120.0477 (10)0.0593 (11)0.0518 (10)0.0020 (8)0.0070 (8)0.0054 (8)
N130.0461 (10)0.0718 (13)0.0516 (11)0.0092 (9)0.0071 (8)0.0003 (9)
C20.0424 (11)0.0556 (13)0.0613 (13)0.0007 (10)0.0102 (10)0.0024 (10)
C30.0576 (14)0.0901 (18)0.0636 (14)0.0080 (13)0.0015 (11)0.0056 (13)
C110.0476 (11)0.0535 (12)0.0526 (11)0.0052 (10)0.0066 (9)0.0063 (10)
C120.0500 (12)0.0704 (15)0.0608 (14)0.0056 (11)0.0075 (10)0.0061 (11)
C130.0630 (14)0.0727 (16)0.0585 (13)0.0013 (12)0.0144 (11)0.0033 (12)
C140.0553 (13)0.0689 (15)0.0496 (12)0.0117 (11)0.0042 (10)0.0110 (11)
C150.0500 (12)0.0703 (15)0.0641 (14)0.0007 (11)0.0013 (10)0.0142 (12)
C160.0496 (12)0.0609 (14)0.0613 (13)0.0022 (11)0.0056 (10)0.0049 (11)
C210.0412 (10)0.0496 (12)0.0500 (11)0.0010 (9)0.0087 (8)0.0030 (9)
C220.0467 (11)0.0556 (12)0.0516 (11)0.0043 (10)0.0109 (9)0.0058 (10)
C230.0455 (11)0.0593 (13)0.0460 (11)0.0018 (10)0.0054 (9)0.0056 (10)
C240.0393 (10)0.0499 (12)0.0505 (11)0.0012 (9)0.0103 (8)0.0004 (9)
C250.0470 (11)0.0601 (13)0.0508 (11)0.0040 (10)0.0152 (9)0.0027 (10)
C260.0491 (12)0.0641 (14)0.0444 (11)0.0010 (10)0.0076 (9)0.0023 (10)
Geometric parameters (Å, º) top
O1—C21.219 (2)C12—H120.93
O11—N11.222 (3)C13—C141.375 (3)
O11—N1i3.317 (3)C13—H130.93
O12—N11.223 (3)C14—C151.371 (3)
N1—C141.462 (3)C15—C161.377 (3)
N1—O11ii3.317 (3)C15—H150.93
N11—N121.267 (2)C16—H160.93
N11—C111.416 (3)C21—C221.382 (3)
N12—N131.322 (2)C21—C261.395 (3)
N13—C211.392 (3)C22—C231.374 (3)
C2—C241.474 (3)C22—H220.93
C2—C31.479 (3)C23—C241.389 (3)
C3—H3A0.96C23—H230.93
C3—H3B0.96C24—C251.393 (3)
C3—H3C0.96C25—C261.371 (3)
C11—C161.387 (3)C25—H250.93
C11—C121.389 (3)C26—H260.93
C12—C131.372 (3)
N1—O11—N1i117.85 (18)C14—C13—H13120.3
O11—N1—O12122.5 (2)C15—C14—C13122.0 (2)
O11—N1—C14118.7 (2)C15—C14—N1119.4 (2)
O12—N1—C14118.8 (2)C13—C14—N1118.6 (2)
O11—N1—O11ii95.94 (16)C14—C15—C16118.6 (2)
O12—N1—O11ii76.10 (16)C14—C15—H15120.7
C14—N1—O11ii98.11 (13)C16—C15—H15120.7
N12—N11—C11112.07 (17)C15—C16—C11120.4 (2)
N11—N12—N13111.74 (17)C15—C16—H16119.8
N12—N13—C21121.09 (19)C11—C16—H16119.8
N12—N13—O1iii128.89 (13)C22—C21—N13118.03 (18)
C21—N13—O1iii107.79 (13)C22—C21—C26119.91 (18)
O1—C2—C24120.52 (19)N13—C21—C26122.06 (18)
O1—C2—C3119.17 (19)C23—C22—C21119.64 (19)
C24—C2—C3120.30 (19)C23—C22—H22120.2
C2—C3—H3A109.5C21—C22—H22120.2
C2—C3—H3B109.5C22—C23—C24121.50 (18)
H3A—C3—H3B109.5C22—C23—H23119.2
C2—C3—H3C109.5C24—C23—H23119.2
H3A—C3—H3C109.5C23—C24—C25118.09 (18)
H3B—C3—H3C109.5C23—C24—C2121.87 (18)
C16—C11—C12119.8 (2)C25—C24—C2120.03 (18)
C16—C11—N11115.30 (19)C26—C25—C24121.18 (18)
C12—C11—N11124.89 (19)C26—C25—H25119.4
C13—C12—C11119.8 (2)C24—C25—H25119.4
C13—C12—H12120.1C25—C26—C21119.66 (18)
C11—C12—H12120.1C25—C26—H26120.2
C12—C13—C14119.3 (2)C21—C26—H26120.2
C12—C13—H13120.3
Symmetry codes: (i) x+3/2, y1/2, z+3/2; (ii) x+3/2, y+1/2, z+3/2; (iii) x+1/2, y1/2, z.

Experimental details

Crystal data
Chemical formulaC14H12N4O3
Mr284.28
Crystal system, space groupMonoclinic, C2/c
Temperature (K)293
a, b, c (Å)14.357 (6), 7.1964 (13), 26.779 (5)
β (°) 100.35 (4)
V3)2721.7 (13)
Z8
Radiation typeMo Kα
µ (mm1)0.10
Crystal size (mm)0.40 × 0.40 × 0.25
Data collection
DiffractometerEnraf-Nonius CAD-4
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
3468, 3266, 1809
Rint0.015
(sin θ/λ)max1)0.660
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.052, 0.142, 1.01
No. of reflections3266
No. of parameters195
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.14, 0.14

Computer programs: CAD-4 EXPRESS (Enraf Nonius, 1994), XCAD4 (Harms & Wocadlo, 1995), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ORTEP-3 for Windows (Farrugia, 1997), DIAMOND (Brandenburg, 1996), WinGX (Farrugia, 1999).

Selected geometric parameters (Å, º) top
O1—C21.219 (2)N11—N121.267 (2)
O11—N11.222 (3)N12—N131.322 (2)
O12—N11.223 (3)
N12—N11—C11112.07 (17)O1—C2—C24120.52 (19)
N11—N12—N13111.74 (17)C24—C2—C3120.30 (19)
N12—N13—C21121.09 (19)
 

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