supplementary materials


HTML versionpdf versioncif file3d viewstructure factorssupplementary materialsCIF check reportsimilar papers Open access

ds2061 scheme

Acta Cryst. (2010). E66, o2789    [ doi:10.1107/S1600536810039905 ]

Quinoxaline: Z' = 1 form

S. Ranganathan, S. Mahapatra, T. S. Thakur and G. R. Desiraju

Abstract top

A new Z' = 1 crystal structure of quinoxaline (or 1,4-diazanaphthalene), C8H6N2, with one-fifth the volume of the earlier known Z' = 5 structure was obtained by means of an in situ cryocrystallization technique.

Related literature top

For the structure of quinoxaline Z' = 5, see: Anthony et al. (1998). For the crystal structure of the hydrated organic compound, see: Namba et al. (1981)

Experimental top

For in situ crystallization, liquid quinoxaline was taken in a Lindemann glass capillary of 0.5 mm diameter. The Z' = 1 form of quinoxaline was obtained by sudden quenching of a capillary, kept in a hot water bath at 70 oC, down to liquid N2 temperature.The capillary was aligned on a Bruker AXS Smart Apex diffractometer and data was collected at 270 K under a liquid N2 flow using the OXFORD N2 cryosystems appratus.

Refinement top

A crystal domain for the Z' = 1 structure was selected and indexed using the RLATT software and refined using SHELXL97. MERG 3 command was used for merging the Friedel pairs. Flack parameter was not reported as compound is achiral.

Computing details top

Data collection: SMART (Bruker, 1998); cell refinement: SAINT (Bruker, 1998); data reduction: SAINT (Bruker, 1998); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: PLATON (Spek, 2009).

Figures top
[Figure 1] Fig. 1. View of the title compound with the atom numbering. Displacement ellipsoids for non-H atoms are drawn at the 50% probability level.
Quinoxaline top
Crystal data top
C8H6N2Dx = 1.295 Mg m−3
Mr = 130.15Melting point = 301–305 K
Orthorhombic, P212121Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2abCell parameters from 734 reflections
a = 4.0212 (13) Åθ = 1.8–26.0°
b = 7.187 (2) ŵ = 0.08 mm−1
c = 23.095 (7) ÅT = 270 K
V = 667.5 (3) Å3Block, pink
Z = 40.40 × 0.30 × 0.30 mm
F(000) = 272
Data collection top
Bruker SMART CCD area-detector
diffractometer		956 independent reflections
Radiation source: fine-focus sealed tube494 reflections with I > 2σ(I)
graphiteRint = 0.045
φ and ω scansθmax = 27.9°, θmin = 1.8°
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)		h = −5→5
Tmin = 0.968, Tmax = 0.976k = −9→9
7556 measured reflectionsl = −29→29
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)] = 0.038Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.106H-atom parameters constrained
S = 0.90 w = 1/[σ2(Fo2) + (0.0652P)2]
where P = (Fo2 + 2Fc2)/3
956 reflections(Δ/σ)max < 0.001
91 parametersΔρmax = 0.13 e Å−3
0 restraintsΔρmin = −0.15 e Å−3
Crystal data top
C8H6N2V = 667.5 (3) Å3
Mr = 130.15Z = 4
Orthorhombic, P212121Mo Kα radiation
a = 4.0212 (13) ŵ = 0.08 mm−1
b = 7.187 (2) ÅT = 270 K
c = 23.095 (7) Å0.40 × 0.30 × 0.30 mm
Data collection top
Bruker SMART CCD area-detector
diffractometer		956 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)		494 reflections with I > 2σ(I)
Tmin = 0.968, Tmax = 0.976Rint = 0.045
7556 measured reflectionsθmax = 27.9°
Refinement top
R[F2 > 2σ(F2)] = 0.038H-atom parameters constrained
wR(F2) = 0.106Δρmax = 0.13 e Å−3
S = 0.90Δρmin = −0.15 e Å−3
956 reflectionsAbsolute structure: ?
91 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
Special details top

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

Refinement. Refinement on F2 for ALL reflections except those flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The observed criterion of F2 > σ(F2) is used only for calculating -R-factor-obs 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
N10.2099 (7)0.1700 (3)0.11405 (9)0.1298 (9)
N20.2375 (6)0.4337 (3)0.20264 (7)0.1131 (8)
C30.3379 (8)0.1356 (3)0.16499 (13)0.1287 (13)
C40.3497 (7)0.2654 (4)0.20858 (9)0.1197 (10)
C5−0.0218 (7)0.6547 (3)0.13897 (10)0.1051 (9)
C6−0.1499 (7)0.6977 (3)0.08739 (11)0.1121 (10)
C7−0.1662 (7)0.5672 (4)0.04429 (10)0.1201 (10)
C8−0.0500 (9)0.3930 (4)0.05303 (8)0.1210 (10)
C90.0873 (6)0.3450 (2)0.10587 (8)0.0900 (8)
C100.1023 (6)0.4767 (3)0.14993 (7)0.0842 (7)
H30.424900.017800.172000.1550*
H40.442300.231300.243900.1440*
H5−0.015100.744400.168000.1260*
H6−0.228900.817400.080700.1340*
H7−0.258200.598800.008700.1440*
H8−0.062200.305400.023500.1450*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.175 (2)0.0880 (13)0.1265 (15)0.0079 (13)−0.0063 (15)−0.0159 (10)
N20.1395 (18)0.1161 (14)0.0837 (11)−0.0085 (13)−0.0069 (11)−0.0063 (9)
C30.156 (3)0.0884 (14)0.1418 (19)0.0102 (16)0.003 (2)0.0182 (15)
C40.134 (2)0.1240 (18)0.1012 (14)0.002 (2)−0.0040 (16)0.0271 (14)
C50.131 (2)0.0819 (13)0.1025 (14)0.0005 (13)0.0090 (14)−0.0123 (10)
C60.1148 (19)0.0976 (14)0.1238 (17)0.0038 (14)0.0150 (17)0.0233 (14)
C70.120 (2)0.154 (2)0.0862 (13)−0.0023 (19)−0.0026 (14)0.0241 (16)
C80.160 (2)0.1223 (17)0.0806 (13)0.0018 (19)−0.0101 (16)−0.0157 (12)
C90.1152 (17)0.0750 (10)0.0797 (11)−0.0063 (12)0.0067 (12)−0.0083 (8)
C100.1008 (16)0.0802 (10)0.0717 (10)−0.0131 (12)0.0090 (10)−0.0034 (8)
Geometric parameters (Å, °) top
N1—C31.308 (4)C8—C91.383 (3)
N1—C91.364 (3)C9—C101.391 (3)
N2—C41.298 (4)C3—H30.9300
N2—C101.369 (3)C4—H40.9300
C3—C41.373 (4)C5—H50.9300
C5—C61.334 (4)C6—H60.9300
C5—C101.396 (3)C7—H70.9300
C6—C71.369 (4)C8—H80.9300
C7—C81.352 (4)
N1···N22.791 (3)H4···N2v2.7900
N2···N12.791 (3)H7···C6vi3.0900
N2···H4i2.7900H8···C8iii3.0000
C6···H7ii3.0900H8···C8iv3.0700
C8···H8iii3.0700H8···H8iii2.4200
C8···H8iv3.0000H8···H8iv2.4200
C3—N1—C9116.2 (2)C5—C10—C9118.38 (18)
C4—N2—C10116.26 (19)N1—C3—H3118.00
N1—C3—C4123.0 (2)C4—C3—H3119.00
N2—C4—C3122.9 (2)N2—C4—H4119.00
C6—C5—C10120.8 (2)C3—C4—H4119.00
C5—C6—C7120.6 (2)C6—C5—H5120.00
C6—C7—C8120.6 (2)C10—C5—H5120.00
C7—C8—C9120.1 (2)C5—C6—H6120.00
N1—C9—C8119.77 (19)C7—C6—H6120.00
N1—C9—C10120.69 (19)C6—C7—H7120.00
C8—C9—C10119.54 (18)C8—C7—H7120.00
N2—C10—C5120.67 (19)C7—C8—H8120.00
N2—C10—C9121.0 (2)C9—C8—H8120.00
C9—N1—C3—C40.3 (4)C10—C5—C6—C70.8 (4)
C3—N1—C9—C100.3 (4)C5—C6—C7—C8−0.6 (4)
C3—N1—C9—C8179.5 (3)C6—C7—C8—C9−0.1 (5)
C10—N2—C4—C30.3 (4)C7—C8—C9—C100.5 (4)
C4—N2—C10—C5−179.3 (2)C7—C8—C9—N1−178.8 (3)
C4—N2—C10—C90.3 (4)N1—C9—C10—N2−0.6 (4)
N1—C3—C4—N2−0.7 (5)C8—C9—C10—C5−0.3 (4)
C6—C5—C10—C9−0.4 (4)N1—C9—C10—C5179.0 (2)
C6—C5—C10—N2179.2 (3)C8—C9—C10—N2−179.8 (3)
Symmetry codes: (i) −x+1, y+1/2, −z+1/2; (ii) x+1/2, −y+3/2, −z; (iii) x−1/2, −y+1/2, −z; (iv) x+1/2, −y+1/2, −z; (v) −x+1, y−1/2, −z+1/2; (vi) x−1/2, −y+3/2, −z.
Table 1
Selected geometric parameters (Å, °) top
N1—C31.308 (4)N2—C41.298 (4)
N1—C91.364 (3)N2—C101.369 (3)
C3—N1—C9116.2 (2)N1—C9—C8119.77 (19)
C4—N2—C10116.26 (19)N1—C9—C10120.69 (19)
N1—C3—C4123.0 (2)N2—C10—C5120.67 (19)
N2—C4—C3122.9 (2)N2—C10—C9121.0 (2)
Acknowledgements top

TST thanks the Indian Institute of Science for a post-doctoral fellowship and GRD thanks the DST for the award of a J. C. Bose fellowship. We thank Professor T. N. Guru Row for useful discussions.

references
References top

Anthony, A., Desiraju, G. R., Jetti, R. K. R., Kuduva, S. S., Madhavi, N. N. L., Nangia, A., Thaimattam, R. & Thalladi, V. R. (1998). Cryst. Eng. 1, 1–18.

Bruker (1998). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.

Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.

Namba, Y., Hirano, K. & Oda, T. (1981). Mem. Osaka Kyoiku Univ. Ser. III Nat. Sci. Appl. Sci. 30, 25–?. Final page number?

Sheldrick, G. M. (1996). SADABS. University of Göttingen, Germany.

Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.

Spek, A. L. (2009). Acta Cryst. D65, 148–155.