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The oxidation of 4-hydroxyazobenzene provided a mixture of two azoxy compounds, which were separated by column chromatography. The isomer with the higher melting point appeared to belong to the α (ONN) series, as determined by X-ray diffraction. The molecule, C
12H
10N
2O
2, is almost planar. The benzene rings are twisted by 11.7 (2) (substituted) and 4.1 (1)° (unsubstituted) with respect to the ONN plane. The molecules are connected to one another by strong O—H
O hydrogen bonds forming chains extended along [001], which are bound by much weaker C—H
O hydrogen bonds forming layers in the
bc plane.
Supporting information
CCDC reference: 146061
Data collection: KUMA Diffraction Software (Kuma, 1998); cell refinement: KUMA Diffraction Software; data reduction: KUMA Diffraction Software; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Sheldrick, 1990); software used to prepare material for publication: SHELXL97.
Crystal data top
C12H10N2O2 | Dx = 1.372 Mg m−3 Dm = 1.37 (1) Mg m−3 Dm measured by flotation |
Mr = 214.22 | Mo Kα radiation, λ = 0.71073 Å |
Orthorhombic, P212121 | Cell parameters from 21 reflections |
a = 7.187 (1) Å | θ = 8–11° |
b = 11.261 (2) Å | µ = 0.10 mm−1 |
c = 12.812 (3) Å | T = 293 K |
V = 1036.9 (3) Å3 | Plate, yellow |
Z = 4 | 0.5 × 0.4 × 0.3 mm |
F(000) = 448 | |
Data collection top
KUMA KM–4 diffractometer | Rint = 0.029 |
Radiation source: fine-focus sealed tube | θmax = 30.1°, θmin = 2.4° |
Graphite monochromator | h = −10→10 |
ω–θ scans | k = −15→15 |
2796 measured reflections | l = −18→18 |
1729 independent reflections | 2 standard reflections every 50 reflections |
1026 reflections with I > 2σ(I) | intensity decay: 0.5% |
Refinement top
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: difference Fourier map |
wR(F2) = 0.096 | All H atoms refined isotropically |
S = 0.99 | Calculated w = 1/[σ2(Fo2) + (0.0252P)2 + 0.113P] where P = (Fo2 + 2Fc2)/3 |
1729 reflections | (Δ/σ)max < 0.001 |
185 parameters | Δρmax = 0.11 e Å−3 |
0 restraints | Δρmin = −0.13 e Å−3 |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
N2 | 0.2024 (3) | 0.24506 (17) | 0.84313 (14) | 0.0548 (5) | |
N1 | 0.1457 (3) | 0.21220 (18) | 0.93209 (14) | 0.0521 (5) | |
O2 | 0.2274 (3) | 0.70176 (16) | 0.68493 (14) | 0.0673 (6) | |
O1 | 0.0781 (3) | 0.27976 (13) | 1.00334 (14) | 0.0608 (5) | |
C1 | 0.1961 (4) | 0.3645 (2) | 0.81248 (16) | 0.0514 (6) | |
C2 | 0.2936 (4) | 0.3844 (2) | 0.72042 (17) | 0.0634 (7) | |
C3 | 0.3056 (4) | 0.4951 (2) | 0.67680 (18) | 0.0626 (7) | |
C4 | 0.2184 (4) | 0.5901 (2) | 0.72317 (16) | 0.0523 (6) | |
C5 | 0.1148 (4) | 0.5715 (2) | 0.81343 (18) | 0.0569 (7) | |
C6 | 0.1035 (4) | 0.4607 (2) | 0.85810 (17) | 0.0544 (6) | |
C1' | 0.1562 (3) | 0.0855 (2) | 0.95302 (16) | 0.0491 (6) | |
C6' | 0.1027 (4) | 0.0457 (2) | 1.04995 (19) | 0.0619 (7) | |
C5' | 0.1099 (5) | −0.0739 (3) | 1.0707 (2) | 0.0736 (9) | |
C4' | 0.1677 (5) | −0.1527 (3) | 0.9970 (2) | 0.0719 (8) | |
C3' | 0.2199 (5) | −0.1121 (2) | 0.89940 (19) | 0.0722 (8) | |
C2' | 0.2135 (4) | 0.0072 (3) | 0.87713 (19) | 0.0625 (7) | |
H22 | 0.298 (6) | 0.703 (3) | 0.632 (3) | 0.108 (12)* | |
H2 | 0.370 (5) | 0.315 (3) | 0.686 (3) | 0.098 (10)* | |
H3 | 0.375 (4) | 0.506 (2) | 0.618 (2) | 0.071 (8)* | |
H5 | 0.045 (3) | 0.639 (2) | 0.8410 (18) | 0.061 (7)* | |
H6 | 0.026 (4) | 0.445 (2) | 0.920 (2) | 0.066 (8)* | |
H6' | 0.059 (4) | 0.105 (2) | 1.096 (2) | 0.080 (9)* | |
H5' | 0.059 (5) | −0.105 (3) | 1.135 (3) | 0.123 (13)* | |
H4' | 0.163 (4) | −0.236 (2) | 1.008 (2) | 0.068 (7)* | |
H3' | 0.254 (4) | −0.171 (2) | 0.848 (2) | 0.093 (10)* | |
H2' | 0.246 (4) | 0.038 (2) | 0.808 (2) | 0.074 (8)* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
N2 | 0.0612 (13) | 0.0648 (13) | 0.0383 (9) | −0.0017 (12) | 0.0060 (10) | −0.0019 (9) |
N1 | 0.0550 (12) | 0.0659 (13) | 0.0355 (8) | −0.0005 (11) | −0.0017 (9) | −0.0047 (9) |
O2 | 0.0893 (15) | 0.0617 (11) | 0.0508 (9) | 0.0053 (11) | 0.0132 (10) | 0.0078 (8) |
O1 | 0.0805 (12) | 0.0664 (11) | 0.0353 (6) | 0.0122 (10) | 0.0062 (9) | −0.0081 (9) |
C1 | 0.0620 (15) | 0.0522 (13) | 0.0399 (10) | −0.0017 (13) | −0.0015 (12) | −0.0011 (10) |
C2 | 0.0830 (19) | 0.0648 (15) | 0.0423 (11) | 0.0008 (16) | 0.0122 (14) | −0.0039 (11) |
C3 | 0.0787 (19) | 0.0697 (17) | 0.0394 (11) | 0.0032 (16) | 0.0133 (14) | 0.0017 (12) |
C4 | 0.0625 (15) | 0.0578 (14) | 0.0367 (10) | −0.0004 (13) | −0.0017 (11) | 0.0029 (10) |
C5 | 0.0637 (16) | 0.0615 (15) | 0.0454 (12) | 0.0065 (14) | 0.0071 (13) | −0.0009 (11) |
C6 | 0.0569 (15) | 0.0663 (16) | 0.0400 (11) | −0.0009 (13) | 0.0064 (12) | 0.0009 (11) |
C1' | 0.0537 (15) | 0.0526 (14) | 0.0410 (11) | 0.0003 (12) | −0.0029 (11) | 0.0019 (10) |
C6' | 0.0772 (19) | 0.0671 (17) | 0.0414 (12) | −0.0005 (15) | 0.0088 (14) | −0.0037 (12) |
C5' | 0.106 (3) | 0.0663 (17) | 0.0486 (13) | −0.0125 (18) | 0.0102 (17) | 0.0082 (13) |
C4' | 0.101 (2) | 0.0572 (15) | 0.0577 (14) | −0.0097 (17) | 0.0046 (18) | 0.0062 (14) |
C3' | 0.101 (2) | 0.0612 (16) | 0.0546 (14) | 0.0033 (17) | 0.0127 (17) | −0.0036 (13) |
C2' | 0.0796 (19) | 0.0662 (16) | 0.0417 (11) | 0.0044 (16) | 0.0087 (14) | 0.0024 (12) |
Geometric parameters (Å, º) top
N2—N1 | 1.266 (3) | C4—C5 | 1.391 (3) |
N2—C1 | 1.402 (3) | C5—C6 | 1.375 (3) |
N1—O1 | 1.284 (2) | C1'—C6' | 1.375 (3) |
N1—C1' | 1.453 (3) | C1'—C2' | 1.376 (3) |
O2—C4 | 1.351 (3) | C6'—C5' | 1.375 (4) |
C1—C2 | 1.390 (3) | C5'—C4' | 1.359 (4) |
C1—C6 | 1.400 (3) | C4'—C3' | 1.383 (4) |
C2—C3 | 1.368 (4) | C3'—C2' | 1.375 (4) |
C3—C4 | 1.375 (3) | | |
| | | |
N1—N2—C1 | 121.5 (2) | C3—C4—C5 | 119.1 (2) |
N2—N1—O1 | 126.1 (2) | C6—C5—C4 | 120.9 (2) |
N2—N1—C1' | 115.9 (2) | C5—C6—C1 | 120.0 (2) |
O1—N1—C1' | 118.0 (2) | C6'—C1'—C2' | 120.9 (2) |
C2—C1—C6 | 118.0 (2) | C6'—C1'—N1 | 118.2 (2) |
C2—C1—N2 | 112.1 (2) | C2'—C1'—N1 | 120.9 (2) |
C6—C1—N2 | 129.9 (2) | C1'—C6'—C5' | 118.9 (2) |
C3—C2—C1 | 121.7 (3) | C4'—C5'—C6' | 121.1 (2) |
C2—C3—C4 | 120.2 (2) | C5'—C4'—C3' | 119.7 (3) |
O2—C4—C3 | 123.1 (2) | C2'—C3'—C4' | 120.1 (3) |
O2—C4—C5 | 117.8 (2) | C1'—C2'—C3' | 119.3 (2) |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O2—H22···O1i | 0.85 (4) | 1.88 (4) | 2.722 (3) | 170 (4) |
C3′—H3′···O2ii | 0.97 (3) | 2.54 (3) | 3.456 (3) | 158 (3) |
Symmetry codes: (i) −x+1/2, −y+1, z−1/2; (ii) x, y−1, z. |
Selected geometric paramterers in some substituted azoxybenzenes top | 4-OH | 4,4'-(OMe)2 | 4,4'-(OPr)2 | 4'-N(Me)2 | cis-4'-Me |
N1-N2 | 1.266 (3) | 1.281 | 1.255 | 1.263 | 1.264 |
N1-O1 | 1.284 (2) | 1.288 | 1.271 | 1.275 | 1.264 |
C1-N2 | 1.402 (3) | 1.428 | 1.421 | 1.415 | 1.427 |
C1'-N1 | 1.453 (3) | 1.445 | 1.475 | 1.442 | 1.470 |
| | | | | |
C1'-N1-O1 | 118.0 (2) | 118.9 | 115.7 | 114.6 | 114.3 |
C1'-N1-N2 | 115.9 (2) | 116.5 | 116.0 | 118.4 | 125.0 |
N2-N1-O1 | 126.1 (2) | 124.6 | 128.3 | 126.7 | 120.5 |
C1-N2-N1 | 121.5 (2) | 120.6 | 118.8 | 118.8 | 119.2 |
C2-C1-N2 | 112.1 (2) | 112.7 | 112.5 | 112.6 | 116.5 |
C6-C1-N2 | 129.9 (2) | 127.5 | 130.0 | 127.8 | 123.4 |
C2'-C1'-N1 | 120.9 (2) | 120.7 | 122.2 | 120.4 | 119.0 |
C6'-C1'-N1 | 118.2 (2) | 119.5 | 117.2 | 119.8 | 118.3 |
| | | | | |
A\dag/B | 4.1 (1) | 3.3 | 4.0 | 8.9 | 55.5 |
B/C | 11.7 (2) | 19.4 | 6.3 | 33.4 | 56.6 |
A/C | 15.6 (1) | 22.2 | 2.3 | 32.6 | 69.9 |
\dag The angle between the planes defined as: A the plane of the benzene
ring connected to the atom N1; B the plane of the azoxy group; C the plane
of the other benzene ring. |
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