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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 π–π inter­actions between the aromatic rings, and the crystal structure is stabilized by van der Waals inter­actions.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807030577/lh2430sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536807030577/lh2430Isup2.hkl
Contains datablock I

CCDC reference: 657662

Key indicators

  • Single-crystal X-ray study
  • T = 294 K
  • Mean [sigma](C-C) = 0.004 Å
  • R factor = 0.050
  • wR factor = 0.137
  • Data-to-parameter ratio = 16.2

checkCIF/PLATON results

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Alert level C PLAT066_ALERT_1_C Predicted and Reported Transmissions Identical . ?
0 ALERT level A = In general: serious problem 0 ALERT level B = Potentially serious problem 1 ALERT level C = Check and explain 0 ALERT level G = General alerts; check 1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 0 ALERT type 2 Indicator that the structure model may be wrong or deficient 0 ALERT type 3 Indicator that the structure quality may be low 0 ALERT type 4 Improvement, methodology, query or suggestion 0 ALERT type 5 Informative message, check

Comment top

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 NN bond. The central NN bond length of 1.228 (4) Å is slightly shorter than the average value of 1.257 Å for azobenzene NN 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.

Related literature top

For background information, see: Dürr & Bouas-Laurent (1990); Martin et al. (1995); Zhao et al. (1999). For the synthetic procedure, see: Xiong et al. (2006). For bond length data, see: Allen et al. (1987).

Experimental top

The title compound was prepared by literature method (Xiong et al., 2006). Single crystals were obtained by slow evaporation of a heptane solution.

Refinement top

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).

Structure description top

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 NN bond. The central NN bond length of 1.228 (4) Å is slightly shorter than the average value of 1.257 Å for azobenzene NN 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.

For background information, see: Dürr & Bouas-Laurent (1990); Martin et al. (1995); Zhao et al. (1999). For the synthetic procedure, see: Xiong et al. (2006). For bond length data, see: Allen et al. (1987).

Computing details top

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.

Figures top
[Figure 1] Fig. 1. The molecular structure with displacement ellipsoids drawn at the 50% probability level [symmetry code: (a) 2 - x, 1 - y, 1 - z]
Bis[3-(chloroacetyl)phenyl]diazene top
Crystal data top
C14H8Cl2N2O2F(000) = 312
Mr = 307.12Dx = 1.521 Mg m3
Monoclinic, P21/cMelting point: 374 K
Hall symbol: -P 2ybcMo Kα radiation, λ = 0.71073 Å
a = 12.7512 (15) ÅCell parameters from 1015 reflections
b = 3.9116 (4) Åθ = 2.5–25.8°
c = 16.6550 (14) ŵ = 0.49 mm1
β = 126.189 (6)°T = 294 K
V = 670.44 (12) Å3Block, red
Z = 20.20 × 0.20 × 0.10 mm
Data collection top
Bruker APEX CCD area-detector
diffractometer
1475 independent reflections
Radiation source: fine-focus sealed tube1109 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.030
φ and ω scansθmax = 27.2°, θmin = 2.0°
Absorption correction: multi-scan
(SADABS; Sheldrick, 2001)
h = 1516
Tmin = 0.909, Tmax = 0.953k = 45
3784 measured reflectionsl = 2021
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)] = 0.050Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.137H-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 parametersΔρmax = 0.34 e Å3
0 restraintsΔρmin = 0.21 e Å3
Crystal data top
C14H8Cl2N2O2V = 670.44 (12) Å3
Mr = 307.12Z = 2
Monoclinic, P21/cMo Kα radiation
a = 12.7512 (15) ŵ = 0.49 mm1
b = 3.9116 (4) ÅT = 294 K
c = 16.6550 (14) Å0.20 × 0.20 × 0.10 mm
β = 126.189 (6)°
Data collection top
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 = 0.953Rint = 0.030
3784 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0500 restraints
wR(F2) = 0.137H-atom parameters constrained
S = 1.06Δρmax = 0.34 e Å3
1475 reflectionsΔρmin = 0.21 e Å3
91 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
Cl10.85788 (6)0.37064 (18)0.72874 (5)0.0627 (3)
O10.63441 (18)0.6568 (6)0.62472 (14)0.0739 (6)
N10.95418 (18)0.5708 (5)0.46251 (13)0.0484 (5)
C10.7350 (2)0.6528 (5)0.54165 (16)0.0405 (5)
C20.84462 (19)0.5682 (6)0.54617 (15)0.0405 (5)
H20.91550.46220.60230.049*
C30.8461 (2)0.6448 (5)0.46547 (16)0.0427 (5)
C40.6292 (2)0.8121 (6)0.45726 (18)0.0494 (6)
H40.55660.87050.45470.059*
C50.7410 (2)0.7994 (6)0.38163 (18)0.0530 (6)
H50.74280.84780.32780.064*
C60.6323 (2)0.8824 (6)0.37792 (18)0.0551 (6)
H60.56120.98630.32140.066*
C70.7233 (2)0.5837 (6)0.62321 (17)0.0488 (6)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cl10.0672 (5)0.0749 (5)0.0573 (4)0.0146 (3)0.0431 (4)0.0124 (3)
O10.0552 (11)0.1128 (18)0.0736 (13)0.0100 (11)0.0490 (11)0.0056 (11)
N10.0470 (11)0.0591 (12)0.0472 (10)0.0016 (9)0.0324 (9)0.0006 (9)
C10.0392 (11)0.0402 (12)0.0454 (11)0.0048 (9)0.0268 (10)0.0066 (9)
C20.0361 (11)0.0427 (12)0.0404 (11)0.0020 (9)0.0214 (9)0.0034 (9)
C30.0417 (12)0.0445 (12)0.0475 (12)0.0053 (9)0.0294 (10)0.0065 (9)
C40.0395 (12)0.0500 (14)0.0567 (13)0.0010 (10)0.0274 (11)0.0061 (10)
C50.0551 (14)0.0593 (16)0.0464 (13)0.0021 (11)0.0309 (12)0.0019 (11)
C60.0459 (14)0.0575 (15)0.0497 (13)0.0044 (11)0.0215 (11)0.0025 (11)
C70.0431 (13)0.0547 (14)0.0529 (13)0.0052 (10)0.0306 (11)0.0076 (11)
Geometric parameters (Å, º) top
Cl1—C71.780 (2)C2—H20.9300
O1—C71.183 (3)C3—C51.379 (3)
N1—N1i1.228 (4)C4—C61.373 (4)
N1—C31.437 (3)C4—H40.9300
C1—C21.395 (3)C5—C61.389 (3)
C1—C41.395 (3)C5—H50.9300
C1—C71.477 (3)C6—H60.9300
C2—C31.388 (3)
N1i—N1—C3114.3 (2)C6—C4—H4120.0
C2—C1—C4120.2 (2)C1—C4—H4120.0
C2—C1—C7123.3 (2)C3—C5—C6119.7 (2)
C4—C1—C7116.5 (2)C3—C5—H5120.1
C3—C2—C1118.9 (2)C6—C5—H5120.1
C3—C2—H2120.6C4—C6—C5120.4 (2)
C1—C2—H2120.6C4—C6—H6119.8
C5—C3—C2120.9 (2)C5—C6—H6119.8
C5—C3—N1115.61 (19)O1—C7—C1126.4 (2)
C2—C3—N1123.46 (19)O1—C7—Cl1118.00 (19)
C6—C4—C1119.9 (2)C1—C7—Cl1115.57 (16)
C4—C1—C2—C30.1 (3)C2—C3—C5—C60.5 (4)
C7—C1—C2—C3179.9 (2)N1—C3—C5—C6179.6 (2)
C1—C2—C3—C50.6 (3)C1—C4—C6—C50.7 (4)
C1—C2—C3—N1179.61 (19)C3—C5—C6—C40.1 (4)
N1i—N1—C3—C5179.1 (3)C2—C1—C7—O1178.0 (2)
N1i—N1—C3—C20.8 (4)C4—C1—C7—O11.8 (4)
C2—C1—C4—C60.7 (3)C2—C1—C7—Cl11.7 (3)
C7—C1—C4—C6179.5 (2)C4—C1—C7—Cl1178.46 (16)
Symmetry code: (i) x+2, y+1, z+1.

Experimental details

Crystal data
Chemical formulaC14H8Cl2N2O2
Mr307.12
Crystal system, space groupMonoclinic, P21/c
Temperature (K)294
a, b, c (Å)12.7512 (15), 3.9116 (4), 16.6550 (14)
β (°) 126.189 (6)
V3)670.44 (12)
Z2
Radiation typeMo Kα
µ (mm1)0.49
Crystal size (mm)0.20 × 0.20 × 0.10
Data collection
DiffractometerBruker APEX CCD area-detector
Absorption correctionMulti-scan
(SADABS; Sheldrick, 2001)
Tmin, Tmax0.909, 0.953
No. of measured, independent and
observed [I > 2σ(I)] reflections
3784, 1475, 1109
Rint0.030
(sin θ/λ)max1)0.644
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.050, 0.137, 1.06
No. of reflections1475
No. of parameters91
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.34, 0.21

Computer programs: SMART (Bruker, 2001), SAINT (Bruker, 2001), SAINT, SHELXTL (Bruker, 2001), SHELXTL, PLATON (Spek, 2003).

 

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