organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890

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

aX-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia
*Correspondence e-mail: hkfun@usm.my

(Received 13 October 2008; accepted 17 October 2008; online 22 October 2008)

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[Fun, H.-K. & Kia, R. (2008). Acta Cryst. E64, o1722-o1723.]). For general background, see: Pal et al. (2005[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.]); Calligaris & Randaccio (1987[Calligaris, M. & Randaccio, L. (1987). Comprehensive Coordination Chemistry, Vol. 2, edited by G. Wilkinson, pp. 715-738. London: Pergamon.]); Hou et al. (2001[Hou, B., Friedman, N., Ruhman, S., Sheves, M. & Ottolenghi, M. (2001). J. Phys. Chem. B, 105, 7042-7048.]); Ren et al. (2002[Ren, S., Wang, R., Komatsu, K., Bonaz-Krause, P., Zyrianov, Y., McKenna, C. E., Csipke, C., Tokes, Z. A. & Lien, E. J. (2002). J. Med. Chem. 45, 410-419.]); Allen et al. (1987[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.]).

[Scheme 1]

Experimental

Crystal data
  • C16H12Cl2F2N2

  • Mr = 341.18

  • Monoclinic, P 21 /n

  • 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[Bruker (2005). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.795, Tmax = 0.983

  • 17372 measured reflections

  • 2139 independent reflections

  • 1705 reflections with I > 2σ(I)

  • Rint = 0.054

Refinement
  • R[F2 > 2σ(F2)] = 0.044

  • wR(F2) = 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

Table 1
Selected interatomic distances (Å)

Cl1⋯F1i 3.087 (1)
C3⋯C6ii 3.429 (3)
Symmetry codes: (i) [x+{\script{1\over 2}}, -y+{\script{1\over 2}}, z-{\script{1\over 2}}]; (ii) x+1, y, z.

Data collection: APEX2 (Bruker, 2005[Bruker (2005). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: APEX2; data reduction: SAINT (Bruker, 2005[Bruker (2005). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); program(s) used to solve structure: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2003[Spek, A. L. (2003). J. Appl. Cryst. 36, 7-13.]).

Supporting information


Comment top

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 CN 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).

Related literature top

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

Experimental top

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 top

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.

Computing details top

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

Figures top
[Figure 1] Fig. 1. The molecular structure of (I) with atom labels and 50% probability displacement ellipsoids [symmetry code: (A) -x, -y, -z + 1].
N,N'-Bis(4-chloro-3-fluorobenzylidene)ethane-1,2-diamine top
Crystal data top
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 top
Bruker SMART APEXII CCD area-detector
diffractometer
2139 independent reflections
Radiation source: fine-focus sealed tube1705 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.054
ϕ and ω scansθmax = 30.2°, θmin = 1.8°
Absorption correction: multi-scan
(SADABS; Bruker, 2005)
h = 66
Tmin = 0.795, Tmax = 0.983k = 3232
17372 measured reflectionsl = 99
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)] = 0.044Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.113H-atom parameters constrained
S = 1.07 w = 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
Crystal data top
C16H12Cl2F2N2V = 720.12 (3) Å3
Mr = 341.18Z = 2
Monoclinic, P21/nMo Kα radiation
a = 4.6542 (1) ŵ = 0.47 mm1
b = 23.1343 (6) ÅT = 100 K
c = 6.9961 (2) Å0.51 × 0.05 × 0.04 mm
β = 107.063 (2)°
Data collection top
Bruker SMART APEXII CCD area-detector
diffractometer
2139 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2005)
1705 reflections with I > 2σ(I)
Tmin = 0.795, Tmax = 0.983Rint = 0.054
17372 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0440 restraints
wR(F2) = 0.113H-atom parameters constrained
S = 1.07Δρmax = 0.99 e Å3
2139 reflectionsΔρmin = 0.34 e Å3
100 parameters
Special details top

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) top
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)
H4A0.53810.06840.23400.020*
C50.3581 (4)0.07550 (8)0.0045 (3)0.0158 (4)
H5A0.28900.03760.01000.019*
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*
C80.0692 (4)0.02721 (8)0.4438 (3)0.0154 (4)
H8A0.28110.02080.37750.019*
H8B0.05100.05900.53720.019*
Atomic displacement parameters (Å2) top
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, º) top
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—C30.5 (3)C4—C5—C6—C7179.29 (16)
F1—C2—C3—C4179.76 (16)C2—C1—C6—C50.2 (3)
C1—C2—C3—C40.2 (3)C2—C1—C6—C7179.57 (16)
F1—C2—C3—Cl10.1 (2)C8—N1—C7—C6178.90 (15)
C1—C2—C3—Cl1179.65 (14)C5—C6—C7—N14.9 (3)
C2—C3—C4—C51.4 (3)C1—C6—C7—N1175.37 (17)
Cl1—C3—C4—C5178.50 (14)C7—N1—C8—C8i133.5 (2)
C3—C4—C5—C61.7 (3)
Symmetry codes: (i) x, y, z+1; (ii) x+1/2, y+1/2, z1/2; (iii) x+1, y, z.

Experimental details

Crystal data
Chemical formulaC16H12Cl2F2N2
Mr341.18
Crystal system, space groupMonoclinic, P21/n
Temperature (K)100
a, b, c (Å)4.6542 (1), 23.1343 (6), 6.9961 (2)
β (°) 107.063 (2)
V3)720.12 (3)
Z2
Radiation typeMo Kα
µ (mm1)0.47
Crystal size (mm)0.51 × 0.05 × 0.04
Data collection
DiffractometerBruker SMART APEXII CCD area-detector
diffractometer
Absorption correctionMulti-scan
(SADABS; Bruker, 2005)
Tmin, Tmax0.795, 0.983
No. of measured, independent and
observed [I > 2σ(I)] reflections
17372, 2139, 1705
Rint0.054
(sin θ/λ)max1)0.708
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.044, 0.113, 1.07
No. of reflections2139
No. of parameters100
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.99, 0.34

Computer programs: APEX2 (Bruker, 2005), SAINT (Bruker, 2005), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2003).

Selected interatomic distances (Å) top
Cl1···F1i3.087 (1)C3···C6ii3.429 (3)
Symmetry codes: (i) x+1/2, y+1/2, z1/2; (ii) x+1, y, z.
 

Acknowledgements

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.

References

First citationAllen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–S19.  CrossRef Web of Science
First citationBruker (2005). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.
First citationCalligaris, M. & Randaccio, L. (1987). Comprehensive Coordination Chemistry, Vol. 2, edited by G. Wilkinson, pp. 715–738. London: Pergamon.
First citationFun, H.-K. & Kia, R. (2008). Acta Cryst. E64, o1722–o1723.  Web of Science CSD CrossRef IUCr Journals
First citationHou, B., Friedman, N., Ruhman, S., Sheves, M. & Ottolenghi, M. (2001). J. Phys. Chem. B, 105, 7042–7048.  Web of Science CrossRef CAS
First citationPal, 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.  Web of Science CSD CrossRef PubMed CAS
First citationRen, S., Wang, R., Komatsu, K., Bonaz-Krause, P., Zyrianov, Y., McKenna, C. E., Csipke, C., Tokes, Z. A. & Lien, E. J. (2002). J. Med. Chem. 45, 410–419.  Web of Science CrossRef PubMed CAS
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals
First citationSpek, A. L. (2003). J. Appl. Cryst. 36, 7–13.  Web of Science CrossRef CAS IUCr Journals

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Follow Acta Cryst. E
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds