Acta Cryst. (2007). E63, o3373 [ doi:10.1107/S1600536807030577 ]
The title molecule, C14H8Cl2N2O2, is a trans-azobenzene which has a crystallographic inversion center at the mid-point of the N=N bond [N=N = 1.228 (4) Å]. There are neither hydrogen bonds nor ![[pi]](/logos/entities/pi_rmgif.gif)
- interactions between the aromatic rings, and the crystal structure is stabilized by van der Waals interactions.
The title compound was prepared by literature method (Xiong et al., 2006). Single crystals were obtained by slow evaporation of a heptane solution.
All H-atoms were discernible in a difference Fourier map. H atoms bound to C atoms were included in calculated positions and allowed to ride during refinement, with C—H = 0.93 Å, and Uiso(H) = 1.2Ueq(C).
Data collection: SMART (Bruker, 2001); cell refinement: SAINT (Bruker, 2001); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Bruker, 2001); program(s) used to refine structure: SHELXTL; molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: SHELXTL.
![[Figure 1]](./lh2430fig1thm.gif)
| Fig. 1. The molecular structure with displacement ellipsoids drawn at the 50% probability level [symmetry code: (a) 2 − x, 1 − y, 1 − z] |
| C14H8Cl2N2O2 | F(000) = 312 |
| Mr = 307.12 | Dx = 1.521 Mg m−3 |
| Monoclinic, P21/c | Melting point: 374 K |
| Hall symbol: -P 2ybc | Mo Kα radiation, λ = 0.71073 Å |
| a = 12.7512 (15) Å | Cell parameters from 1015 reflections |
| b = 3.9116 (4) Å | θ = 2.5–25.8° |
| c = 16.6550 (14) Å | µ = 0.49 mm−1 |
| β = 126.189 (6)° | T = 294 K |
| V = 670.44 (12) Å3 | Block, red |
| Z = 2 | 0.20 × 0.20 × 0.10 mm |
| Bruker APEX CCD area-detector diffractometer | 1475 independent reflections |
| Radiation source: fine-focus sealed tube | 1109 reflections with I > 2σ(I) |
| graphite | Rint = 0.030 |
| φ and ω scans | θmax = 27.2°, θmin = 2.0° |
| Absorption correction: multi-scan (SADABS; Sheldrick, 2001) | h = −15→16 |
| Tmin = 0.909, Tmax = 0.953 | k = −4→5 |
| 3784 measured reflections | l = −20→21 |
| 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)] = 0.050 | Hydrogen site location: inferred from neighbouring sites |
| wR(F2) = 0.137 | H-atom parameters constrained |
| S = 1.06 | w = 1/[σ2(Fo2) + (0.0695P)2 + 0.1223P] where P = (Fo2 + 2Fc2)/3 |
| 1475 reflections | (Δ/σ)max < 0.001 |
| 91 parameters | Δρmax = 0.34 e Å−3 |
| 0 restraints | Δρmin = −0.21 e Å−3 |
| C14H8Cl2N2O2 | V = 670.44 (12) Å3 |
| Mr = 307.12 | Z = 2 |
| Monoclinic, P21/c | Mo Kα radiation |
| a = 12.7512 (15) Å | µ = 0.49 mm−1 |
| b = 3.9116 (4) Å | T = 294 K |
| c = 16.6550 (14) Å | 0.20 × 0.20 × 0.10 mm |
| β = 126.189 (6)° |
| Bruker APEX CCD area-detector diffractometer | 1475 independent reflections |
| Absorption correction: multi-scan (SADABS; Sheldrick, 2001) | 1109 reflections with I > 2σ(I) |
| Tmin = 0.909, Tmax = 0.953 | Rint = 0.030 |
| 3784 measured reflections | θmax = 27.2° |
| R[F2 > 2σ(F2)] = 0.050 | H-atom parameters constrained |
| wR(F2) = 0.137 | Δρmax = 0.34 e Å−3 |
| S = 1.06 | Δρmin = −0.21 e Å−3 |
| 1475 reflections | Absolute structure: ? |
| 91 parameters | Flack parameter: ? |
| 0 restraints | Rogers parameter: ? |
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 | ||
| Cl1 | 0.85788 (6) | 0.37064 (18) | 0.72874 (5) | 0.0627 (3) | |
| O1 | 0.63441 (18) | 0.6568 (6) | 0.62472 (14) | 0.0739 (6) | |
| N1 | 0.95418 (18) | 0.5708 (5) | 0.46251 (13) | 0.0484 (5) | |
| C1 | 0.7350 (2) | 0.6528 (5) | 0.54165 (16) | 0.0405 (5) | |
| C2 | 0.84462 (19) | 0.5682 (6) | 0.54617 (15) | 0.0405 (5) | |
| H2 | 0.9155 | 0.4622 | 0.6023 | 0.049* | |
| C3 | 0.8461 (2) | 0.6448 (5) | 0.46547 (16) | 0.0427 (5) | |
| C4 | 0.6292 (2) | 0.8121 (6) | 0.45726 (18) | 0.0494 (6) | |
| H4 | 0.5566 | 0.8705 | 0.4547 | 0.059* | |
| C5 | 0.7410 (2) | 0.7994 (6) | 0.38163 (18) | 0.0530 (6) | |
| H5 | 0.7428 | 0.8478 | 0.3278 | 0.064* | |
| C6 | 0.6323 (2) | 0.8824 (6) | 0.37792 (18) | 0.0551 (6) | |
| H6 | 0.5612 | 0.9863 | 0.3214 | 0.066* | |
| C7 | 0.7233 (2) | 0.5837 (6) | 0.62321 (17) | 0.0488 (6) |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| Cl1 | 0.0672 (5) | 0.0749 (5) | 0.0573 (4) | 0.0146 (3) | 0.0431 (4) | 0.0124 (3) |
| O1 | 0.0552 (11) | 0.1128 (18) | 0.0736 (13) | 0.0100 (11) | 0.0490 (11) | 0.0056 (11) |
| N1 | 0.0470 (11) | 0.0591 (12) | 0.0472 (10) | 0.0016 (9) | 0.0324 (9) | 0.0006 (9) |
| C1 | 0.0392 (11) | 0.0402 (12) | 0.0454 (11) | −0.0048 (9) | 0.0268 (10) | −0.0066 (9) |
| C2 | 0.0361 (11) | 0.0427 (12) | 0.0404 (11) | −0.0020 (9) | 0.0214 (9) | −0.0034 (9) |
| C3 | 0.0417 (12) | 0.0445 (12) | 0.0475 (12) | −0.0053 (9) | 0.0294 (10) | −0.0065 (9) |
| C4 | 0.0395 (12) | 0.0500 (14) | 0.0567 (13) | 0.0010 (10) | 0.0274 (11) | −0.0061 (10) |
| C5 | 0.0551 (14) | 0.0593 (16) | 0.0464 (13) | −0.0021 (11) | 0.0309 (12) | 0.0019 (11) |
| C6 | 0.0459 (14) | 0.0575 (15) | 0.0497 (13) | 0.0044 (11) | 0.0215 (11) | 0.0025 (11) |
| C7 | 0.0431 (13) | 0.0547 (14) | 0.0529 (13) | −0.0052 (10) | 0.0306 (11) | −0.0076 (11) |
| Cl1—C7 | 1.780 (2) | C2—H2 | 0.9300 |
| O1—C7 | 1.183 (3) | C3—C5 | 1.379 (3) |
| N1—N1i | 1.228 (4) | C4—C6 | 1.373 (4) |
| N1—C3 | 1.437 (3) | C4—H4 | 0.9300 |
| C1—C2 | 1.395 (3) | C5—C6 | 1.389 (3) |
| C1—C4 | 1.395 (3) | C5—H5 | 0.9300 |
| C1—C7 | 1.477 (3) | C6—H6 | 0.9300 |
| C2—C3 | 1.388 (3) | ||
| N1i—N1—C3 | 114.3 (2) | C6—C4—H4 | 120.0 |
| C2—C1—C4 | 120.2 (2) | C1—C4—H4 | 120.0 |
| C2—C1—C7 | 123.3 (2) | C3—C5—C6 | 119.7 (2) |
| C4—C1—C7 | 116.5 (2) | C3—C5—H5 | 120.1 |
| C3—C2—C1 | 118.9 (2) | C6—C5—H5 | 120.1 |
| C3—C2—H2 | 120.6 | C4—C6—C5 | 120.4 (2) |
| C1—C2—H2 | 120.6 | C4—C6—H6 | 119.8 |
| C5—C3—C2 | 120.9 (2) | C5—C6—H6 | 119.8 |
| C5—C3—N1 | 115.61 (19) | O1—C7—C1 | 126.4 (2) |
| C2—C3—N1 | 123.46 (19) | O1—C7—Cl1 | 118.00 (19) |
| C6—C4—C1 | 119.9 (2) | C1—C7—Cl1 | 115.57 (16) |
| C4—C1—C2—C3 | −0.1 (3) | C2—C3—C5—C6 | 0.5 (4) |
| C7—C1—C2—C3 | −179.9 (2) | N1—C3—C5—C6 | −179.6 (2) |
| C1—C2—C3—C5 | −0.6 (3) | C1—C4—C6—C5 | −0.7 (4) |
| C1—C2—C3—N1 | 179.61 (19) | C3—C5—C6—C4 | 0.1 (4) |
| N1i—N1—C3—C5 | −179.1 (3) | C2—C1—C7—O1 | 178.0 (2) |
| N1i—N1—C3—C2 | 0.8 (4) | C4—C1—C7—O1 | −1.8 (4) |
| C2—C1—C4—C6 | 0.7 (3) | C2—C1—C7—Cl1 | −1.7 (3) |
| C7—C1—C4—C6 | −179.5 (2) | C4—C1—C7—Cl1 | 178.46 (16) |
| Symmetry codes: (i) −x+2, −y+1, −z+1. |
The authors acknowledge financial support from the State `863' Science Foundation (2002 A A333110).
Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–19.
Bruker (2001). or (2000)???. SMART, SAINT and SHELXTL. Bruker AXS Inc., Madison, Wisconsin, USA. Please check date; 2001 in CIF.
Dürr, H. & Bouas-Laurent, H. (1990). Photochromism: Molecules and Systems. Amsterdam: Elsevier.
Martin, P. J., Petty, M. C., Bryce, M. R. & Bloor, D. (1995). An Introduction to Molecular Electronics, ch. 6. New York: Oxford University Press.
Sheldrick, G. M. (1990). SHELXS97. University of Göttingen, Germany. Not cited in CIF; should this replace SHELXTL in `programs used to solve structure' above?
Sheldrick, G. M. (1997). SHELXL97. University of Göttingen, Germany. Not cited in CIF; should this replace SHELXTL in `programs used to refine structure' above?
Sheldrick, G. M. (2001). SADABS. Version 2.10. Bruker AXS Inc., Madison, Wisconsin, USA.
Spek, A. L. (2003). J. Appl. Cryst. 36, 7–13.
Xiong, C. X., Niu, Y. S., Zhou, W. & Dong, L. J. (2006). J. Chem. Res. pp. 139–140.
Zhao, W., Wu, C. X. & Iwamoto, M. (1999). Journal name? 312, 572–577.
In azobenzene compounds, a conversion from the trans to cis form can lead to photochromism. Photochromic compounds are of great interest for the control and measurement of radiation intensity, optical computers and display systems (Dürr & Bouas-Laurent, 1990) and for potential applications in molecular electronic devices (Martin et al., 1995). In addition, azo polymers have interest in various fields (Zhao et al., 1999). As a part of our investigation of preparing azo polymers, we report the crystal structure of the title compound.
There is an inversion center at the mid-point of the N═N bond. The central N═N bond length of 1.228 (4) Å is slightly shorter than the average value of 1.257 Å for azobenzene N═N bonds (Allen et al., 1987). But the C1—N1 bond length of 1.437 (3) Å is almost the same as the average value (1.43 Å). The molecular structure is shown in Fig. 1.