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Acta Crystallogr Sect E Struct Rep Online. 2008 November 1; 64(Pt 11): o2169.
Published online 2008 October 22. doi:  10.1107/S1600536808033916
PMCID: PMC2959635

N,N′-Bis(4-chloro-3-fluoro­benzyl­idene)ethane-1,2-diamine

Abstract

The asymmetric unit of the title Schiff base compound, C16H12Cl2F2N2, contains one half of the centrosymmetric mol­ecule. Mol­ecules related by translation along the a axis form stacks with short inter­molecular C(...)C distances of 3.429 (3) Å. The crystal packing also exhibits short inter­molecular Cl(...)F contacts of 3.087 (1) Å.

Related literature

For a related structure, see Fun & Kia (2008 [triangle]). For general background, see: Pal et al. (2005 [triangle]); Calligaris & Randaccio (1987 [triangle]); Hou et al. (2001 [triangle]); Ren et al. (2002 [triangle]); Allen et al. (1987 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-64-o2169-scheme1.jpg

Experimental

Crystal data

  • C16H12Cl2F2N2
  • M r = 341.18
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-64-o2169-efi1.jpg
  • a = 4.6542 (1) Å
  • b = 23.1343 (6) Å
  • c = 6.9961 (2) Å
  • β = 107.063 (2)°
  • V = 720.12 (3) Å3
  • Z = 2
  • Mo Kα radiation
  • μ = 0.47 mm−1
  • T = 100.0 (1) K
  • 0.51 × 0.05 × 0.04 mm

Data collection

  • Bruker SMART APEXII CCD area-detector diffractometer
  • Absorption correction: multi-scan (SADABS; Bruker, 2005 [triangle]) T min = 0.795, T max = 0.983
  • 17372 measured reflections
  • 2139 independent reflections
  • 1705 reflections with I > 2σ(I)
  • R int = 0.054

Refinement

  • R[F 2 > 2σ(F 2)] = 0.044
  • wR(F 2) = 0.113
  • S = 1.07
  • 2139 reflections
  • 100 parameters
  • H-atom parameters constrained
  • Δρmax = 0.99 e Å−3
  • Δρmin = −0.34 e Å−3

Data collection: APEX2 (Bruker, 2005 [triangle]); cell refinement: APEX2; data reduction: SAINT (Bruker, 2005 [triangle]); program(s) used to solve structure: SHELXTL (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2003 [triangle]).

Table 1
Selected interatomic distances (Å)

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808033916/cv2465sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808033916/cv2465Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Acknowledgments

HKF and RK thank the Malaysian government and Universiti Sains Malaysia for the Science Fund grant No. 305/PFIZIK/613312. RK thanks Universiti Sains Malaysia for the award of a post-doctoral research fellowship. We acknowledge Professor A. L. Spek for providing us with a symmetry operation code.

supplementary crystallographic information

Comment

Schiff bases are one of most prevalent mixed-donor ligands in the field of coordination chemistry. There has been growing interest in Schiff base ligands, mainly because of their wide application in the field of biochemistry, synthesis and catalysis (Pal et al., 2005; Hou et al., 2001; Ren et al., 2002). Many Schiff base complexes have been structurally characterized, but only a relatively small number of free Schiff bases have been characterized (Calligaris & Randaccio, 1987). As an extension of our work (Fun & Kia, 2008) on the structural characterization of Schiff base ligands, the title compound (I) is reported here.

The molecule of the title compound, (I) (Fig. 1), lies across a crystallographic inversion centre and adopts an E configuration with respect to the azomethine C═N bond. The bond lengths and angles are within normal ranges (Allen et al., 1987) and are comparable with those in the related structure (Fun & Kia, 2008). The planar units are parallel by symmetry but extend in opposite directions from the dimethylene bridge. The interesting feature of the crystal structure is the short intermolecular Cl···F interaction (Table 1) with the distance of 3.087 (1) Å, which is shorter than the sum of the van der Waals radii of these atoms. The molecules related by translation along the a axis form stacks with short intermolecular C···C distances of 3.429 (3) Å (Table 1).

Experimental

The synthetic method has been described earlier (Fun & Kia, 2008). Single crystals suitable for X-ray diffraction were obtained by evaporation of an ethanol solution at room temperature.

Refinement

All of the hydrogen atoms were positioned geometrically with C—H = 0.93 or 0.97 Å and refined in riding mode with Uiso (H) = 1.2 Ueq (C). The highest residual peak of 0.99 e. Å-3 is located 0.25 Å from atom H4A.

Figures

Fig. 1.
The molecular structure of (I) with atom labels and 50% probability displacement ellipsoids [symmetry code: (A) -x, -y, -z + 1].

Crystal data

C16H12Cl2F2N2F(000) = 348
Mr = 341.18Dx = 1.573 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 3479 reflections
a = 4.6542 (1) Åθ = 3.2–30.0°
b = 23.1343 (6) ŵ = 0.47 mm1
c = 6.9961 (2) ÅT = 100 K
β = 107.063 (2)°Needle, colourless
V = 720.12 (3) Å30.51 × 0.05 × 0.04 mm
Z = 2

Data collection

Bruker SMART APEXII CCD area-detector diffractometer2139 independent reflections
Radiation source: fine-focus sealed tube1705 reflections with I > 2σ(I)
graphiteRint = 0.054
[var phi] and ω scansθmax = 30.2°, θmin = 1.8°
Absorption correction: multi-scan (SADABS; Bruker, 2005)h = −6→6
Tmin = 0.795, Tmax = 0.983k = −32→32
17372 measured reflectionsl = −9→9

Refinement

Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.044Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.113H-atom parameters constrained
S = 1.07w = 1/[σ2(Fo2) + (0.0465P)2 + 0.6198P] where P = (Fo2 + 2Fc2)/3
2139 reflections(Δ/σ)max < 0.001
100 parametersΔρmax = 0.99 e Å3
0 restraintsΔρmin = −0.34 e Å3

Special details

Experimental. The low-temperature data was collected with the Oxford Cyrosystem Cobra low-temperature attachment.
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)

xyzUiso*/Ueq
Cl10.77503 (10)0.17566 (2)−0.30608 (7)0.01931 (14)
F10.6479 (3)0.24323 (5)0.0088 (2)0.0285 (3)
N10.0845 (4)0.04180 (7)0.2962 (2)0.0165 (3)
C10.4139 (4)0.17032 (8)0.1460 (3)0.0170 (4)
H1A0.38650.19590.24170.020*
C20.5544 (4)0.18819 (8)0.0072 (3)0.0178 (4)
C30.6002 (4)0.15091 (8)−0.1355 (3)0.0162 (4)
C40.5045 (4)0.09402 (8)−0.1403 (3)0.0166 (4)
H4A0.53810.0684−0.23400.020*
C50.3581 (4)0.07550 (8)−0.0045 (3)0.0158 (4)
H5A0.28900.0376−0.01000.019*
C60.3139 (4)0.11314 (8)0.1400 (3)0.0146 (3)
C70.1624 (4)0.09406 (8)0.2865 (3)0.0153 (4)
H7A0.12270.12100.37420.018*
C8−0.0692 (4)0.02721 (8)0.4438 (3)0.0154 (4)
H8A−0.28110.02080.37750.019*
H8B−0.05100.05900.53720.019*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
Cl10.0208 (2)0.0198 (2)0.0212 (2)−0.00002 (17)0.01230 (17)0.00367 (18)
F10.0397 (7)0.0162 (6)0.0378 (8)−0.0075 (5)0.0242 (6)−0.0041 (5)
N10.0177 (7)0.0177 (8)0.0162 (8)−0.0006 (6)0.0082 (6)0.0024 (6)
C10.0184 (8)0.0155 (9)0.0192 (9)−0.0001 (7)0.0088 (7)−0.0015 (7)
C20.0175 (8)0.0138 (8)0.0241 (10)−0.0015 (6)0.0093 (7)0.0016 (7)
C30.0135 (8)0.0185 (9)0.0185 (9)0.0003 (7)0.0077 (7)0.0048 (7)
C40.0168 (8)0.0165 (9)0.0171 (9)0.0003 (7)0.0061 (7)−0.0004 (7)
C50.0173 (8)0.0131 (8)0.0185 (9)−0.0008 (6)0.0073 (7)0.0017 (7)
C60.0139 (7)0.0152 (8)0.0155 (8)0.0006 (6)0.0057 (6)0.0027 (7)
C70.0147 (8)0.0169 (9)0.0152 (9)0.0003 (6)0.0057 (7)0.0012 (7)
C80.0164 (8)0.0155 (8)0.0165 (9)0.0003 (6)0.0081 (7)0.0020 (7)

Geometric parameters (Å, °)

Cl1—C31.7274 (19)C4—C51.389 (3)
F1—C21.345 (2)C4—H4A0.9300
N1—C71.270 (2)C5—C61.395 (3)
N1—C81.458 (2)C5—H5A0.9300
C1—C21.383 (3)C6—C71.472 (3)
C1—C61.399 (3)C7—H7A0.9300
C1—H1A0.9300C8—C8i1.524 (4)
C2—C31.383 (3)C8—H8A0.9700
C3—C41.387 (3)C8—H8B0.9700
Cl1···F1ii3.087 (1)C3···C6iii3.429 (3)
C7—N1—C8117.74 (17)C4—C5—H5A119.7
C2—C1—C6118.90 (18)C6—C5—H5A119.7
C2—C1—H1A120.5C5—C6—C1119.56 (17)
C6—C1—H1A120.5C5—C6—C7121.36 (16)
F1—C2—C3118.59 (17)C1—C6—C7119.08 (17)
F1—C2—C1119.72 (17)N1—C7—C6121.70 (18)
C3—C2—C1121.70 (17)N1—C7—H7A119.2
C2—C3—C4119.55 (17)C6—C7—H7A119.2
C2—C3—Cl1119.73 (14)N1—C8—C8i109.64 (18)
C4—C3—Cl1120.72 (15)N1—C8—H8A109.7
C3—C4—C5119.63 (18)C8i—C8—H8A109.7
C3—C4—H4A120.2N1—C8—H8B109.7
C5—C4—H4A120.2C8i—C8—H8B109.7
C4—C5—C6120.65 (17)H8A—C8—H8B108.2
C6—C1—C2—F1178.99 (16)C4—C5—C6—C11.0 (3)
C6—C1—C2—C3−0.5 (3)C4—C5—C6—C7−179.29 (16)
F1—C2—C3—C4−179.76 (16)C2—C1—C6—C50.2 (3)
C1—C2—C3—C4−0.2 (3)C2—C1—C6—C7−179.57 (16)
F1—C2—C3—Cl10.1 (2)C8—N1—C7—C6−178.90 (15)
C1—C2—C3—Cl1179.65 (14)C5—C6—C7—N14.9 (3)
C2—C3—C4—C51.4 (3)C1—C6—C7—N1−175.37 (17)
Cl1—C3—C4—C5−178.50 (14)C7—N1—C8—C8i−133.5 (2)
C3—C4—C5—C6−1.7 (3)

Symmetry codes: (i) −x, −y, −z+1; (ii) x+1/2, −y+1/2, z−1/2; (iii) x+1, y, z.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: CV2465).

References

  • Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–S19.
  • Bruker (2005). APEX2, SAINT and SADABS Bruker AXS Inc., Madison, Wisconsin, USA.
  • Calligaris, M. & Randaccio, L. (1987). Comprehensive Coordination Chemistry, Vol. 2, edited by G. Wilkinson, pp. 715–738. London: Pergamon.
  • Fun, H.-K. & Kia, R. (2008). Acta Cryst. E64, o1722–o1723. [PMC free article] [PubMed]
  • Hou, B., Friedman, N., Ruhman, S., Sheves, M. & Ottolenghi, M. (2001). J. Phys. Chem. B, 105, 7042–7048.
  • Pal, S., Barik, A. K., Gupta, S., Hazra, A., Kar, S. K., Peng, S.-M., Lee, G.-H., Butcher, R. J., El Fallah, M. S. & Ribas, J. (2005). Inorg. Chem.44, 3880–3889. [PubMed]
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Articles from Acta Crystallographica Section E: Structure Reports Online are provided here courtesy of International Union of Crystallography