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ISSN: 2056-9890

Quinoxaline: Z′ = 1 form

aSolid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560 012, Karnataka, India
*Correspondence e-mail: desiraju@sscu.iisc.ernet.in

(Received 28 September 2010; accepted 6 October 2010; online 9 October 2010)

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

For the structure of quinoxaline Z′ = 5, see: Anthony et al. (1998[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.]). For the crystal structure of the hydrated organic compound, see: Namba et al. (1981[Namba, Y., Hirano, K. & Oda, T. (1981). Mem. Osaka Kyoiku Univ. Ser. III Nat. Sci. Appl. Sci. 30, 25-29.]).

[Scheme 1]

Experimental

Crystal data
  • C8H6N2

  • Mr = 130.15

  • Orthorhombic, P 21 21 21

  • a = 4.0212 (13) Å

  • b = 7.187 (2) Å

  • c = 23.095 (7) Å

  • V = 667.5 (3) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.08 mm−1

  • T = 270 K

  • 0.40 × 0.30 × 0.30 mm

Data collection
  • Bruker SMART CCD area-detector diffractometer

  • Absorption correction: multi-scan (SADABS; Sheldrick, 1996[Sheldrick, G. M. (1996). SADABS. University of Göttingen, Germany.]) Tmin = 0.968, Tmax = 0.976

  • 7556 measured reflections

  • 956 independent reflections

  • 494 reflections with I > 2σ(I)

  • Rint = 0.045

Refinement
  • R[F2 > 2σ(F2)] = 0.038

  • wR(F2) = 0.106

  • S = 0.90

  • 956 reflections

  • 91 parameters

  • H-atom parameters constrained

  • Δρmax = 0.13 e Å−3

  • Δρmin = −0.15 e Å−3

Data collection: SMART (Bruker, 1998[Bruker (1998). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 1998[Bruker (1998). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997[Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.]); software used to prepare material for publication: PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]).

Supporting information


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.

Structure description 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)

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 m3
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 mm1
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)
Graphite monochromatorRint = 0.045
φ and ω scansθmax = 27.9°, θmin = 1.8°
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
h = 55
Tmin = 0.968, Tmax = 0.976k = 99
7556 measured reflectionsl = 2929
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 Å3
0 restraintsΔρmin = 0.15 e Å3
Crystal data top
C8H6N2V = 667.5 (3) Å3
Mr = 130.15Z = 4
Orthorhombic, P212121Mo Kα radiation
a = 4.0212 (13) ŵ = 0.08 mm1
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 reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0380 restraints
wR(F2) = 0.106H-atom parameters constrained
S = 0.90Δρmax = 0.13 e Å3
956 reflectionsΔρmin = 0.15 e Å3
91 parameters
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)
C50.0218 (7)0.6547 (3)0.13897 (10)0.1051 (9)
C60.1499 (7)0.6977 (3)0.08739 (11)0.1121 (10)
C70.1662 (7)0.5672 (4)0.04429 (10)0.1201 (10)
C80.0500 (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*
H50.015100.744400.168000.1260*
H60.228900.817400.080700.1340*
H70.258200.598800.008700.1440*
H80.062200.305400.023500.1450*
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, º) 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—C80.6 (4)
C3—N1—C9—C8179.5 (3)C6—C7—C8—C90.1 (5)
C10—N2—C4—C30.3 (4)C7—C8—C9—C100.5 (4)
C4—N2—C10—C5179.3 (2)C7—C8—C9—N1178.8 (3)
C4—N2—C10—C90.3 (4)N1—C9—C10—N20.6 (4)
N1—C3—C4—N20.7 (5)C8—C9—C10—C50.3 (4)
C6—C5—C10—C90.4 (4)N1—C9—C10—C5179.0 (2)
C6—C5—C10—N2179.2 (3)C8—C9—C10—N2179.8 (3)
Symmetry codes: (i) x+1, y+1/2, z+1/2; (ii) x+1/2, y+3/2, z; (iii) x1/2, y+1/2, z; (iv) x+1/2, y+1/2, z; (v) x+1, y1/2, z+1/2; (vi) x1/2, y+3/2, z.

Experimental details

Crystal data
Chemical formulaC8H6N2
Mr130.15
Crystal system, space groupOrthorhombic, P212121
Temperature (K)270
a, b, c (Å)4.0212 (13), 7.187 (2), 23.095 (7)
V3)667.5 (3)
Z4
Radiation typeMo Kα
µ (mm1)0.08
Crystal size (mm)0.40 × 0.30 × 0.30
Data collection
DiffractometerBruker SMART CCD area-detector
Absorption correctionMulti-scan
(SADABS; Sheldrick, 1996)
Tmin, Tmax0.968, 0.976
No. of measured, independent and
observed [I > 2σ(I)] reflections
7556, 956, 494
Rint0.045
(sin θ/λ)max1)0.658
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.038, 0.106, 0.90
No. of reflections956
No. of parameters91
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.13, 0.15

Computer programs: SMART (Bruker, 1998), SAINT (Bruker, 1998), SHELXTL (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997), PLATON (Spek, 2009).

Selected geometric parameters (Å, º) 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

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 also thank Professor T. N. Guru Row for useful discussions.

References

First citationAnthony, 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.  CrossRef CAS Google Scholar
First citationBruker (1998). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationFarrugia, L. J. (1997). J. Appl. Cryst. 30, 565.  CrossRef IUCr Journals Google Scholar
First citationNamba, Y., Hirano, K. & Oda, T. (1981). Mem. Osaka Kyoiku Univ. Ser. III Nat. Sci. Appl. Sci. 30, 25–29.  CAS Google Scholar
First citationSheldrick, G. M. (1996). SADABS. University of Göttingen, Germany.  Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationSpek, A. L. (2009). Acta Cryst. D65, 148–155.  Web of Science CrossRef CAS IUCr Journals Google Scholar

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Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
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