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Acta Crystallogr Sect E Struct Rep Online. 2009 January 1; 65(Pt 1): o106.
Published online 2008 December 13. doi:  10.1107/S1600536808041627
PMCID: PMC2968030

2,3,5-Triphenyl­pyrazine

Abstract

In the title mol­ecule, C22H16N2, the pyrazine ring deviates very slightly from planarity [maximum deviation 0.044 (3) Å], tending towards a twist-boat conformation. The phenyl ring at position 3 makes dihedral angles of 64.0 (2) and 45.8 (2)°, respectively, with the phenyl rings at positions 2 and 5. The dihedral angle between the phenyl rings at positions 2 and 5 is 49.7 (2)°. A C—H(...)π inter­action is found in the crystal structure, but no classical hydrogen bonds form.

Related literature

For the biological properties of pyrazines, see: Foks et al. (2004 [triangle]); Premkumar & Govindarajan (2005 [triangle]); Sondhi et al. (2005 [triangle]).

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Object name is e-65-0o106-scheme1.jpg

Experimental

Crystal data

  • C22H16N2
  • M r = 308.37
  • Orthorhombic, An external file that holds a picture, illustration, etc.
Object name is e-65-0o106-efi1.jpg
  • a = 15.563 (2) Å
  • b = 6.2005 (9) Å
  • c = 16.845 (3) Å
  • V = 1625.5 (4) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 0.07 mm−1
  • T = 296 (2) K
  • 0.44 × 0.35 × 0.21 mm

Data collection

  • Bruker APEXII CCD diffractometer
  • Absorption correction: multi-scan (SADABS; Bruker, 2004 [triangle]) T min = 0.968, T max = 0.985
  • 17890 measured reflections
  • 1730 independent reflections
  • 1109 reflections with I > 2σ(I)
  • R int = 0.091

Refinement

  • R[F 2 > 2σ(F 2)] = 0.050
  • wR(F 2) = 0.129
  • S = 1.02
  • 1730 reflections
  • 218 parameters
  • 1 restraint
  • H-atom parameters constrained
  • Δρmax = 0.13 e Å−3
  • Δρmin = −0.13 e Å−3

Data collection: APEX2 (Bruker, 2004 [triangle]); cell refinement: SAINT-NT (Bruker, 2004 [triangle]); data reduction: SAINT-NT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: ORTEP-3 (Farrugia, 1997 [triangle]); software used to prepare material for publication: PLATON (Spek, 2003 [triangle]).

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808041627/wn2297sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808041627/wn2297Isup2.hkl

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

Acknowledgments

AT thanks the UGC, India, for the award of a Minor Research Project [File No. MRP-2355/06(UGC-SERO), Link No. 2355, 10/01/2007]. RJB acknowledges the NSF–MRI program for funding to purchase the X-ray CCD diffractometer.

supplementary crystallographic information

Comment

Pyrazines are heterocycles which exhibit nutty, roasted or earth flavouring agents. 2-Cyanopyrazine derivatives show anticancer, anti-inflammatory and analgesic activities (Sondhi et al., 2005). Pyrazine derivatives exhibit tuberculostatic activity (Foks et al., 2004) and antimicrobial activity (Premkumar & Govindarajan, 2005).

In the title molecule, C22H16N2, (Fig. 1), the pyrazine ring deviates very slightly from planarity, tending towards a twist-boat conformation. The phenyl ring at position 3 makes dihedral angles of 64.0 (2)° and 45.8 (2)° with the phenyl rings at positions 2 and 5, respectively. The dihedral angle between the phenyl rings at positions 2 and 5 is 49.7 (2)°. A C53—H53···π interaction involving the phenyl (C21–C26) ring at position 2 is found in the crystal structure, but no classical hydrogen bonds.

Experimental

To a homogeneous solution of benzil (1.05 g, 0.005 mol) and 1-phenylethanediamine dihydrochloride (1.04 g, 0.005 mol) in ethanol, sodium acetate trihydrate (2.04 g, 0.015 mol) was added. The precipitated sodium chloride was filtered off and the filtrate was refluxed for 2 h. On completion of the reaction, as indicated by TLC, the reaction mixture was poured into crushed ice and the resulting solid was filtered off and purified by column chromatography on silica gel. Elution with benzene: petroleum ether (4:1 v/v) at 333–353 K gave the product in pure form. Yield 1.6 g (80%).

Refinement

H atoms were positioned geometrically and allowed to ride on their parent atoms, with C—H = 0.93 Å and Uiso(H) = 1.2 times Ueq(C). In the absence of significant anomalous scattering effects Friedel pairs have been merged.

Figures

Fig. 1.
The molecular structure of the title compound, showing the atom-numbering scheme and displacement ellipsoids drawn at the 50% probability level. H atoms are shown as small spheres of arbitrary radius.

Crystal data

C22H16N2Dx = 1.260 Mg m3
Mr = 308.37Melting point: 421 K
Orthorhombic, Pna21Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2nCell parameters from 2955 reflections
a = 15.563 (2) Åθ = 2.4–21.2°
b = 6.2005 (9) ŵ = 0.07 mm1
c = 16.845 (3) ÅT = 296 K
V = 1625.5 (4) Å3Chunk, colourless
Z = 40.44 × 0.35 × 0.21 mm
F(000) = 648

Data collection

Bruker APEXII CCD diffractometer1730 independent reflections
Radiation source: fine-focus sealed tube1109 reflections with I > 2σ(I)
graphiteRint = 0.091
[var phi] and ω scansθmax = 26.5°, θmin = 2.4°
Absorption correction: multi-scan (SADABS; Bruker, 2004)h = −19→19
Tmin = 0.968, Tmax = 0.985k = −7→7
17890 measured reflectionsl = −20→19

Refinement

Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.050H-atom parameters constrained
wR(F2) = 0.129w = 1/[σ2(Fo2) + (0.0653P)2 + 0.1081P] where P = (Fo2 + 2Fc2)/3
S = 1.02(Δ/σ)max = 0.001
1730 reflectionsΔρmax = 0.13 e Å3
218 parametersΔρmin = −0.13 e Å3
1 restraintExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.015 (3)

Special details

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 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 > 2σ(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
N10.2355 (2)0.1296 (5)0.19242 (19)0.0547 (12)
N40.3436 (2)−0.1252 (5)0.10173 (19)0.0487 (11)
C20.2412 (3)0.1612 (5)0.1141 (2)0.0463 (12)
C30.3009 (3)0.0395 (6)0.0686 (2)0.0447 (12)
C50.3329 (3)−0.1640 (6)0.1791 (2)0.0477 (12)
C60.2822 (3)−0.0252 (7)0.2244 (3)0.0557 (14)
C210.1810 (3)0.3188 (6)0.0793 (2)0.0480 (12)
C220.1658 (3)0.5110 (6)0.1192 (3)0.0547 (16)
C230.1074 (3)0.6577 (7)0.0897 (3)0.0670 (17)
C240.0622 (3)0.6125 (8)0.0212 (3)0.0717 (17)
C250.0760 (3)0.4218 (8)−0.0185 (3)0.0683 (19)
C260.1359 (3)0.2775 (8)0.0110 (3)0.0610 (17)
C310.3243 (3)0.0908 (7)−0.0142 (2)0.0500 (14)
C320.3486 (3)0.2977 (7)−0.0358 (3)0.0583 (16)
C330.3772 (3)0.3414 (7)−0.1116 (3)0.0653 (17)
C340.3783 (3)0.1810 (8)−0.1676 (3)0.0660 (17)
C350.3525 (3)−0.0229 (8)−0.1474 (3)0.0687 (17)
C360.3261 (3)−0.0692 (6)−0.0714 (2)0.0577 (16)
C510.3770 (3)−0.3528 (6)0.2136 (2)0.0483 (12)
C520.4302 (3)−0.4792 (7)0.1662 (3)0.0610 (17)
C530.4682 (3)−0.6620 (7)0.1961 (3)0.0730 (19)
C540.4543 (3)−0.7247 (8)0.2734 (3)0.0747 (19)
C550.4017 (4)−0.6012 (8)0.3210 (3)0.0770 (19)
C560.3635 (3)−0.4195 (7)0.2911 (3)0.0667 (17)
H60.28114−0.042590.279210.0669*
H220.195100.540890.166010.0653*
H230.098400.787570.116050.0803*
H240.022340.711090.001860.0859*
H250.045490.39011−0.064470.0819*
H260.145840.14928−0.016120.0727*
H320.345520.408420.001370.0699*
H330.395840.47943−0.124640.0783*
H340.396400.21058−0.219020.0788*
H350.35281−0.13135−0.185550.0820*
H360.30936−0.20876−0.058330.0693*
H520.44015−0.439490.113710.0731*
H530.50365−0.744460.163660.0872*
H540.48007−0.848830.293250.0894*
H550.39220−0.641120.373520.0927*
H560.32749−0.338880.323670.0800*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
N10.062 (2)0.052 (2)0.050 (2)0.0055 (17)0.0027 (16)−0.0004 (16)
N40.0533 (19)0.0458 (18)0.047 (2)0.0009 (15)0.0024 (15)0.0030 (15)
C20.057 (2)0.042 (2)0.040 (2)−0.0052 (18)0.0015 (17)−0.0036 (18)
C30.055 (2)0.039 (2)0.040 (2)0.0020 (18)0.0004 (16)−0.0025 (16)
C50.055 (2)0.047 (2)0.041 (2)−0.0069 (18)−0.0003 (17)0.0022 (18)
C60.069 (3)0.057 (2)0.041 (2)−0.002 (2)−0.0020 (19)−0.001 (2)
C210.051 (2)0.047 (2)0.046 (2)−0.0008 (17)0.0017 (18)−0.0008 (18)
C220.060 (3)0.050 (2)0.054 (3)0.000 (2)0.0030 (19)−0.0013 (19)
C230.067 (3)0.055 (3)0.079 (3)0.011 (2)0.007 (3)0.001 (2)
C240.066 (3)0.077 (3)0.072 (3)0.013 (3)0.002 (3)0.008 (3)
C250.067 (3)0.085 (4)0.053 (3)0.012 (3)−0.006 (2)0.004 (2)
C260.067 (3)0.062 (3)0.054 (3)0.002 (2)−0.004 (2)−0.002 (2)
C310.054 (2)0.054 (3)0.042 (2)0.0078 (19)−0.0010 (18)0.0036 (18)
C320.077 (3)0.047 (2)0.051 (3)0.003 (2)0.009 (2)0.002 (2)
C330.077 (3)0.056 (3)0.063 (3)0.006 (2)0.012 (2)0.015 (2)
C340.076 (3)0.076 (3)0.046 (3)0.015 (3)0.009 (2)0.014 (3)
C350.089 (3)0.070 (3)0.047 (3)0.017 (3)0.001 (2)−0.006 (2)
C360.079 (3)0.046 (2)0.048 (3)0.009 (2)0.001 (2)−0.004 (2)
C510.049 (2)0.045 (2)0.051 (2)−0.0034 (18)−0.0025 (18)0.0050 (19)
C520.064 (3)0.056 (3)0.063 (3)−0.001 (2)0.005 (2)0.013 (2)
C530.066 (3)0.061 (3)0.092 (4)0.012 (2)0.008 (3)0.011 (3)
C540.075 (3)0.056 (3)0.093 (4)0.007 (3)−0.019 (3)0.019 (3)
C550.098 (4)0.072 (3)0.061 (3)0.010 (3)−0.013 (3)0.012 (3)
C560.085 (3)0.064 (3)0.051 (3)0.013 (2)−0.010 (2)0.006 (2)

Geometric parameters (Å, °)

N1—C21.337 (5)C51—C561.386 (6)
N1—C61.319 (6)C52—C531.374 (6)
N4—C31.340 (5)C53—C541.376 (7)
N4—C51.336 (5)C54—C551.378 (7)
C2—C31.421 (6)C55—C561.370 (7)
C2—C211.475 (6)C6—H60.9300
C3—C311.476 (5)C22—H220.9300
C5—C61.395 (6)C23—H230.9300
C5—C511.476 (6)C24—H240.9300
C21—C221.389 (6)C25—H250.9300
C21—C261.372 (6)C26—H260.9300
C22—C231.379 (6)C32—H320.9300
C23—C241.380 (7)C33—H330.9300
C24—C251.375 (7)C34—H340.9300
C25—C261.384 (7)C35—H350.9300
C31—C321.386 (6)C36—H360.9300
C31—C361.383 (5)C52—H520.9300
C32—C331.379 (7)C53—H530.9300
C33—C341.371 (7)C54—H540.9300
C34—C351.370 (7)C55—H550.9300
C35—C361.375 (6)C56—H560.9300
C51—C521.392 (6)
N1···N42.768 (4)C34···H54viii3.0900
N4···N12.768 (4)C35···H54viii2.9000
N1···H222.6600C35···H56v3.0600
N1···H35i2.8800C51···H22ii3.0200
N4···H362.8000C52···H23vii3.0000
N4···H522.4700C56···H62.6700
C5···C22ii3.441 (6)H6···C562.6700
C6···C34iii3.587 (7)H6···H562.1100
C6···C54iv3.366 (7)H22···N12.6600
C21···C323.253 (6)H22···C5iv2.8300
C22···C5iv3.441 (6)H22···C51iv3.0200
C26···C323.405 (7)H23···C52ix3.0000
C26···C313.181 (7)H25···C33ix3.0900
C31···C263.181 (7)H26···C32.8900
C32···C263.405 (7)H26···C312.8000
C32···C213.253 (6)H32···C22.9300
C34···C6v3.587 (7)H32···C212.9300
C35···C56v3.576 (7)H32···H52iv2.5800
C54···C6ii3.366 (7)H35···N1x2.8800
C56···C35iii3.576 (7)H36···N42.8000
C2···H322.9300H52···N42.4700
C3···H262.8900H52···H32ii2.5800
C5···H22ii2.8300H54···C34xi3.0900
C6···H562.6600H54···C35xi2.9000
C21···H322.9300H55···C24xii3.0000
C24···H55vi3.0000H56···C62.6600
C31···H262.8000H56···H62.1100
C33···H25vii3.0900H56···C35iii3.0600
C2—N1—C6118.2 (4)C54—C55—C56120.1 (5)
C3—N4—C5118.8 (3)C51—C56—C55121.8 (4)
N1—C2—C3119.9 (3)N1—C6—H6119.00
N1—C2—C21116.6 (3)C5—C6—H6119.00
C3—C2—C21123.5 (3)C21—C22—H22120.00
N4—C3—C2120.3 (3)C23—C22—H22120.00
N4—C3—C31115.8 (4)C22—C23—H23120.00
C2—C3—C31123.8 (3)C24—C23—H23120.00
N4—C5—C6119.6 (4)C23—C24—H24120.00
N4—C5—C51118.0 (3)C25—C24—H24120.00
C6—C5—C51122.5 (3)C24—C25—H25120.00
N1—C6—C5122.5 (4)C26—C25—H25120.00
C2—C21—C22119.0 (3)C21—C26—H26119.00
C2—C21—C26122.3 (4)C25—C26—H26119.00
C22—C21—C26118.6 (4)C31—C32—H32119.00
C21—C22—C23120.3 (4)C33—C32—H32120.00
C22—C23—C24120.2 (4)C32—C33—H33120.00
C23—C24—C25120.1 (4)C34—C33—H33120.00
C24—C25—C26119.1 (5)C33—C34—H34120.00
C21—C26—C25121.7 (4)C35—C34—H34120.00
C3—C31—C32121.0 (4)C34—C35—H35120.00
C3—C31—C36120.6 (4)C36—C35—H35120.00
C32—C31—C36118.4 (4)C31—C36—H36120.00
C31—C32—C33120.9 (4)C35—C36—H36120.00
C32—C33—C34119.9 (4)C51—C52—H52120.00
C33—C34—C35119.7 (5)C53—C52—H52120.00
C34—C35—C36120.8 (4)C52—C53—H53120.00
C31—C36—C35120.3 (4)C54—C53—H53120.00
C5—C51—C52119.8 (3)C53—C54—H54120.00
C5—C51—C56122.5 (4)C55—C54—H54120.00
C52—C51—C56117.6 (4)C54—C55—H55120.00
C51—C52—C53120.7 (4)C56—C55—H55120.00
C52—C53—C54120.8 (4)C51—C56—H56119.00
C53—C54—C55119.1 (5)C55—C56—H56119.00
C6—N1—C2—C3−4.3 (6)C2—C21—C22—C23−177.5 (4)
C6—N1—C2—C21173.4 (4)C26—C21—C22—C23−0.9 (7)
C2—N1—C6—C5−3.9 (6)C2—C21—C26—C25176.3 (4)
C5—N4—C3—C2−4.0 (6)C22—C21—C26—C25−0.2 (7)
C5—N4—C3—C31172.3 (4)C21—C22—C23—C241.4 (7)
C3—N4—C5—C6−4.0 (6)C22—C23—C24—C25−0.8 (7)
C3—N4—C5—C51176.9 (4)C23—C24—C25—C26−0.3 (7)
N1—C2—C3—N48.5 (6)C24—C25—C26—C210.8 (7)
N1—C2—C3—C31−167.5 (4)C3—C31—C32—C33174.6 (4)
C21—C2—C3—N4−169.0 (4)C36—C31—C32—C33−2.6 (7)
C21—C2—C3—C3115.0 (6)C3—C31—C36—C35−176.4 (4)
N1—C2—C21—C2242.2 (6)C32—C31—C36—C350.8 (7)
N1—C2—C21—C26−134.2 (4)C31—C32—C33—C342.8 (7)
C3—C2—C21—C22−140.2 (4)C32—C33—C34—C35−1.3 (7)
C3—C2—C21—C2643.4 (6)C33—C34—C35—C36−0.5 (7)
N4—C3—C31—C32−126.1 (4)C34—C35—C36—C310.7 (7)
N4—C3—C31—C3651.0 (6)C5—C51—C52—C53−176.5 (4)
C2—C3—C31—C3250.0 (7)C56—C51—C52—C53−0.6 (7)
C2—C3—C31—C36−132.9 (5)C5—C51—C56—C55176.7 (5)
N4—C5—C6—N18.4 (7)C52—C51—C56—C550.9 (7)
C51—C5—C6—N1−172.6 (4)C51—C52—C53—C540.3 (7)
N4—C5—C51—C522.3 (6)C52—C53—C54—C55−0.2 (7)
N4—C5—C51—C56−173.5 (4)C53—C54—C55—C560.5 (8)
C6—C5—C51—C52−176.8 (4)C54—C55—C56—C51−0.9 (8)
C6—C5—C51—C567.5 (7)

Symmetry codes: (i) −x+1/2, y+1/2, z+1/2; (ii) x, y−1, z; (iii) −x+1/2, y−1/2, z+1/2; (iv) x, y+1, z; (v) −x+1/2, y+1/2, z−1/2; (vi) −x+1/2, y+3/2, z−1/2; (vii) x+1/2, −y+1/2, z; (viii) −x+1, −y−1, z−1/2; (ix) x−1/2, −y+1/2, z; (x) −x+1/2, y−1/2, z−1/2; (xi) −x+1, −y−1, z+1/2; (xii) −x+1/2, y−3/2, z+1/2.

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
C53—H53···Cgxiii0.932.983.909 (5)174

Symmetry codes: (xiii) x+1/2, −y−1/2, z.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: WN2297).

References

  • Bruker (2004). APEX2, SAINT-NT and SADABS Bruker AXS Inc., Madison, Wisconsin, USA.
  • Farrugia, L. J. (1997). J. Appl. Cryst.30, 565.
  • Foks, H., Trapkaoska, I., Janowiec, M., Zwolska, Z. & Augustynowicz-Kopec, E. (2004). Chem. Heterocycl. Cmpd, 40, 1185–1193.
  • Premkumar, T. & Govindarajan, S. (2005). World J. Microbiol. Biotechnol.21, 479–480.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Sondhi, S. M., Singh, N., Rajvanshi, S. & Johar, M. (2005). Indian J. Chem.44B, 387–399.
  • Spek, A. L. (2003). J. Appl. Cryst.36, 7–13.

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