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The crystal structure of
m-nitroaniline has been examined at several temperatures over the 90–350 K range. Thermal evolution of the lattice parameters reveals a weak anomaly at 110 K and an important one at 300 K. The thermal expansion coefficients have been calculated at several temperatures and the principal axes cross-sections of the tensor were drawn. The lattice contraction along the
b axis direction has been observed. The rigid-body analysis including an attached rigid group has provided the values of the translation and libration tensors at temperatures studied. The results indicate that
m-nitroaniline undergoes a glass transition around 130 K arising from freezing molecular librations and translations. From above 340 K the growing plasticity of the
m-nitroaniline crystal results in the loss of X-ray diffraction reflections. This is probably a second-order phase transition. It is coupled with a considerable increase in the nitro group torsion amplitude, but the NH
O hydrogen bonds are preserved. Analysis of the temperature evolution of short intermolecular distances enabled us to consider the occurrence of reorienting aggregates of hydrogen-bonded molecules in the high-temperature plastic phase.
Supporting information
CCDC references: 166507; 169363; 169364
Data collection: Kuma KM4CCD Software; cell refinement: Kuma KM4CCD Software; data reduction: Kuma KM4CCD Software; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3; software used to prepare material for publication: SHELXL97.
'3-nitro-phenylamine'
top
Crystal data top
C6H6N2O2 | Dx = 1.492 Mg m−3 |
Mr = 138.13 | Mo Kα radiation, λ = 0.71073 Å |
Orthorhombic, Pca21 | Cell parameters from 1415 reflections |
a = 18.873 (2) Å | θ = 3.4–28.2° |
b = 6.5212 (9) Å | µ = 0.12 mm−1 |
c = 4.9980 (7) Å | T = 110 K |
V = 615.13 (14) Å3 | Plate, yellow |
Z = 4 | 1.02 × 0.67 × 0.18 mm |
F(000) = 288 | |
Data collection top
Kuma Diffraction KM4CCD diffractometer | 1305 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.025 |
Graphite monochromator | θmax = 29.6°, θmin = 3.1° |
ω scans | h = −26→25 |
4413 measured reflections | k = −9→8 |
1357 independent reflections | l = −6→5 |
Refinement top
Refinement on F2 | Hydrogen site location: inferred from neighbouring sites |
Least-squares matrix: full | Fixed |
R[F2 > 2σ(F2)] = 0.040 | w = 1/[σ2(Fo2) + (0.0638P)2 + 0.1839P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.108 | (Δ/σ)max = 0.001 |
S = 1.10 | Δρmax = 0.27 e Å−3 |
1357 reflections | Δρmin = −0.29 e Å−3 |
92 parameters | Extinction correction: SHELXL, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
1 restraint | Extinction coefficient: 0.29 (2) |
Primary atom site location: structure-invariant direct methods | Absolute structure: Flack H D (1983), Acta Cryst. A39, 876-881 |
Secondary atom site location: difference Fourier map | Absolute structure parameter: −0.5 (15) |
Crystal data top
C6H6N2O2 | V = 615.13 (14) Å3 |
Mr = 138.13 | Z = 4 |
Orthorhombic, Pca21 | Mo Kα radiation |
a = 18.873 (2) Å | µ = 0.12 mm−1 |
b = 6.5212 (9) Å | T = 110 K |
c = 4.9980 (7) Å | 1.02 × 0.67 × 0.18 mm |
Data collection top
Kuma Diffraction KM4CCD diffractometer | 1305 reflections with I > 2σ(I) |
4413 measured reflections | Rint = 0.025 |
1357 independent reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.040 | Fixed |
wR(F2) = 0.108 | Δρmax = 0.27 e Å−3 |
S = 1.10 | Δρmin = −0.29 e Å−3 |
1357 reflections | Absolute structure: Flack H D (1983), Acta Cryst. A39, 876-881 |
92 parameters | Absolute structure parameter: −0.5 (15) |
1 restraint | |
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 | x | y | z | Uiso*/Ueq | |
N1 | 0.14178 (7) | 0.57722 (19) | 0.2389 (3) | 0.0204 (3) | |
O1 | 0.10120 (7) | 0.43100 (18) | 0.2081 (3) | 0.0320 (3) | |
C1 | 0.12426 (8) | 0.7287 (2) | 0.4454 (3) | 0.0177 (3) | |
O2 | 0.19549 (6) | 0.60121 (19) | 0.1048 (3) | 0.0298 (3) | |
N2 | 0.19586 (7) | 1.21243 (19) | 0.7026 (3) | 0.0219 (3) | |
H2A | 0.2344 | 1.2261 | 0.6052 | 0.026* | |
H2B | 0.1854 | 1.3049 | 0.8246 | 0.026* | |
C2 | 0.16823 (8) | 0.8982 (2) | 0.4699 (3) | 0.0180 (3) | |
H2 | 0.2086 | 0.9140 | 0.3581 | 0.022* | |
C4 | 0.09147 (8) | 1.0157 (2) | 0.8234 (3) | 0.0212 (3) | |
H4 | 0.0796 | 1.1147 | 0.9555 | 0.025* | |
C3 | 0.15155 (8) | 1.0450 (2) | 0.6637 (3) | 0.0179 (3) | |
C6 | 0.06434 (8) | 0.6964 (2) | 0.5997 (4) | 0.0212 (3) | |
H6 | 0.0352 | 0.5791 | 0.5755 | 0.025* | |
C5 | 0.04893 (8) | 0.8435 (2) | 0.7910 (4) | 0.0228 (3) | |
H5 | 0.0085 | 0.8263 | 0.9021 | 0.027* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
N1 | 0.0227 (6) | 0.0186 (5) | 0.0201 (7) | 0.0011 (4) | −0.0027 (6) | −0.0046 (5) |
O1 | 0.0355 (6) | 0.0247 (5) | 0.0358 (8) | −0.0076 (5) | 0.0016 (6) | −0.0127 (6) |
C1 | 0.0193 (6) | 0.0176 (6) | 0.0161 (7) | 0.0022 (5) | −0.0029 (6) | −0.0043 (5) |
O2 | 0.0285 (6) | 0.0316 (6) | 0.0293 (8) | −0.0008 (5) | 0.0055 (6) | −0.0130 (5) |
N2 | 0.0227 (6) | 0.0200 (5) | 0.0230 (7) | −0.0014 (4) | −0.0005 (5) | −0.0074 (5) |
C2 | 0.0176 (6) | 0.0189 (6) | 0.0175 (7) | −0.0001 (5) | −0.0006 (6) | −0.0029 (5) |
C4 | 0.0210 (6) | 0.0232 (7) | 0.0195 (8) | 0.0036 (5) | −0.0007 (6) | −0.0052 (6) |
C3 | 0.0180 (6) | 0.0190 (6) | 0.0167 (8) | 0.0025 (5) | −0.0046 (5) | −0.0027 (5) |
C6 | 0.0200 (6) | 0.0216 (7) | 0.0220 (8) | −0.0014 (5) | −0.0013 (6) | −0.0023 (6) |
C5 | 0.0197 (6) | 0.0281 (7) | 0.0205 (8) | −0.0006 (5) | 0.0027 (6) | −0.0016 (6) |
Geometric parameters (Å, º) top
N1—O2 | 1.2253 (19) | C2—C3 | 1.398 (2) |
N1—O1 | 1.2328 (16) | C2—H2 | 0.9500 |
N1—C1 | 1.4665 (19) | C4—C5 | 1.390 (2) |
C1—C6 | 1.385 (2) | C4—C3 | 1.400 (2) |
C1—C2 | 1.3874 (18) | C4—H4 | 0.9500 |
N2—C3 | 1.3892 (17) | C6—C5 | 1.385 (2) |
N2—H2A | 0.8800 | C6—H6 | 0.9500 |
N2—H2B | 0.8800 | C5—H5 | 0.9500 |
| | | |
O2—N1—O1 | 122.99 (14) | C5—C4—C3 | 120.76 (14) |
O2—N1—C1 | 119.05 (12) | C5—C4—H4 | 119.6 |
O1—N1—C1 | 117.96 (13) | C3—C4—H4 | 119.6 |
C6—C1—C2 | 124.09 (13) | N2—C3—C2 | 119.98 (14) |
C6—C1—N1 | 118.26 (12) | N2—C3—C4 | 120.99 (14) |
C2—C1—N1 | 117.64 (13) | C2—C3—C4 | 118.98 (13) |
C3—N2—H2A | 120.0 | C1—C6—C5 | 116.77 (13) |
C3—N2—H2B | 120.0 | C1—C6—H6 | 121.6 |
H2A—N2—H2B | 120.0 | C5—C6—H6 | 121.6 |
C1—C2—C3 | 118.16 (14) | C6—C5—C4 | 121.24 (14) |
C1—C2—H2 | 120.9 | C6—C5—H5 | 119.4 |
C3—C2—H2 | 120.9 | C4—C5—H5 | 119.4 |
| | | |
O2—N1—C1—C6 | −178.39 (15) | C1—C2—C3—C4 | −0.2 (2) |
O1—N1—C1—C6 | 1.9 (2) | C5—C4—C3—N2 | −177.33 (15) |
O2—N1—C1—C2 | 2.9 (2) | C5—C4—C3—C2 | 0.1 (2) |
O1—N1—C1—C2 | −176.83 (15) | C2—C1—C6—C5 | −0.8 (2) |
C6—C1—C2—C3 | 0.6 (2) | N1—C1—C6—C5 | −179.36 (15) |
N1—C1—C2—C3 | 179.18 (14) | C1—C6—C5—C4 | 0.6 (2) |
C1—C2—C3—N2 | 177.23 (14) | C3—C4—C5—C6 | −0.3 (3) |
Experimental details
Crystal data |
Chemical formula | C6H6N2O2 |
Mr | 138.13 |
Crystal system, space group | Orthorhombic, Pca21 |
Temperature (K) | 110 |
a, b, c (Å) | 18.873 (2), 6.5212 (9), 4.9980 (7) |
V (Å3) | 615.13 (14) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.12 |
Crystal size (mm) | 1.02 × 0.67 × 0.18 |
|
Data collection |
Diffractometer | Kuma Diffraction KM4CCD diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 4413, 1357, 1305 |
Rint | 0.025 |
(sin θ/λ)max (Å−1) | 0.694 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.040, 0.108, 1.10 |
No. of reflections | 1357 |
No. of parameters | 92 |
No. of restraints | 1 |
H-atom treatment | Fixed |
Δρmax, Δρmin (e Å−3) | 0.27, −0.29 |
Absolute structure | Flack H D (1983), Acta Cryst. A39, 876-881 |
Absolute structure parameter | −0.5 (15) |
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