6,7-Difluoro-1,2,3,4-tetra­hydro­quin­oxa­line-5,8-dicarbonitrile

Qu, B.-H.; Jia, X.-C.; Li, J.; He, M.-Y.

doi:10.1107/S1600536813003206

Volume 69
Part 3
Page o376
March 2013

Received 29 October 2012
Accepted 31 January 2013
Online 13 February 2013

Key indicators
Single-crystal X-ray study
T = 293 K
Mean (C-C) = 0.002 Å
R = 0.043
wR = 0.140
Data-to-parameter ratio = 14.8
Details

6,7-Difluoro-1,2,3,4-tetrahydroquinoxaline-5,8-dicarbonitrile

Bao-Hua Qu,^a Xiao-Chuan Jia,^b Jing Li ^b and Ming-Yang He ^a ^*

^aKey Laboratory of Fine Petrochemical Technology, Changzhou University, Changzhou 213164, People's Republic of China, and ^bTianjin Entry-Exit Inspection and Quarantine Bureau, Tianjin 300457, People's Republic of China
Correspondence e-mail: hemingyangjpu@yahoo.com

In the title compound, C₁₀H₆F₂N₄, the C_ar-N bonds are slightly shortened with respect to a standard aniline C-N bond [1.3580 (16) and 1.3618 (16) versus 1.39 Å], thus indicating some [pi] - [pi] conjgation with the electron-acceptor CN groups. The molecule, except for two C atom of the ethylene bridge, is nearly planar, the largest deviation of the other non-H atoms from the mean plane being 0.309 (2) Å. The N-C-C-N torsion angle involving the ethylene bridge is 50.23 (18)°. In the crystal, molecules are connected by pairs of N-HN hydrogen bonds into chains along [21-1].

Related literature

For general background to the synthesis and use of tetrafluoroterephthalonitrile and its derivatives, see: Meazza et al. (2007). For reference structural data on tetrafluoroterephthalic acid, see: Orthaber et al. (2010). For standard bond lengths, see: Allen et al. (1987). For hydrogen bonding graph-set descriptors, see: Etter (1990).

Experimental

Crystal data

C₁₀H₆F₂N₄
M_r = 220.19
Triclinic, $[P \overline 1]$
a = 5.2173 (9) Å
b = 8.7011 (15) Å
c = 11.1453 (19) Å
= 75.545 (2)°
= 81.854 (2)°
= 76.427 (2)°
V = 474.40 (14) Å³
Z = 2
Mo K radiation
= 0.13 mm^-1
T = 293 K
0.28 × 0.24 × 0.16 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2003) T_min = 0.964, T_max = 0.980
4155 measured reflections
2141 independent reflections
1816 reflections with I > 2(I)
R_int = 0.026

Refinement

R[F² > 2(F²)] = 0.043
wR(F²) = 0.140
S = 1.06
2141 reflections
145 parameters
H-atom parameters constrained
_max = 0.29 e Å^-3
_min = -0.23 e Å^-3

Table 1
Hydrogen-bond geometry (Å, °)

D-HA	D-H	HA	DA	D-HA
N3-H3N1ⁱ	0.86	2.29	3.075 (2)	152
N4-H4N2ⁱⁱ	0.86	2.21	3.0358 (19)	160
Symmetry codes: (i) -x+1, -y+1, -z+1; (ii) -x-1, -y, -z+2.

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL and DIAMOND (Brandenburg, 2005); software used to prepare material for publication: SHELXTL.

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: YK2078 ).

References

Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1-19.
Brandenburg, K. (2005). DIAMOND. Crystal Impact GbR, Bonn, Germany.
Bruker (2007). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.
Etter, M. C. (1990). Acc. Chem. Res. 23, 120-126.
Meazza, G., Bettarini, F. & Fornara, L. (2007). WO Patent No. 2007101587.
Orthaber, A., Seidel, C., Belaj, F., Albering, J. H., Pietschnig, R. & Ruschewitz, U. (2010). Inorg. Chem. 49, 9350-9357.
Sheldrick, G. M. (2003). SADABS. University of Göttingen, Germany.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.

organic compounds