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Acta Cryst. (2009). E65, o2225    [ doi:10.1107/S1600536809033029 ]

5,6-Diphenylpyrazine-2,3-dicarbonitrile

T. Hökelek, E. Yalçin, Z. Seferoglu and E. Sahin

Abstract top

In the title compound, C18H10N4, the pyrazine ring is oriented at dihedral angles of 48.08 (7) and 44.80 (7)° with respect to the phenyl rings, while the dihedral angle between the phenyl rings is 49.47 (7)°. In the crystal structure, weak [pi]-[pi] contacts between pyrazine and phenyl rings [centroid-centroid distance = 3.813 (1) Å] may stabilize the structure.

Comment top

2,3-Dicyanopyrazine derivatives have become a potential subject of investigation because of their wide variety of applications, which include heterocycles for bioactive substances, coloring matters, nonlinear optical (NLO) and electroluminescence (EL) materials (Hou et al., 1993; Jaung et al., 1996). They are also the intermediate compounds to synthesize phthalocyanine dyes, which is nowadays a very important class of dyes. On the other hand, it has been found that a group of 2,3-dicyanopyrazine derivatives have very good herbicidial activity in treatment of the soil of water-submerged paddies, foliage of weeds in the growth period, and the soil of upland farms, these compounds generally tend to form a rigid chemical-treated layer in the surface of the soil, and have the ability to control barnyard grass and other annual and perennial weeds excellently with substantially no phytotoxicity to transplanted rise plants (Takematsu et al., 1981). The present study was undertaken in order to ascertain the crystal structure of the title compound.

In the molecule of the title compound, (Fig. 1), the bond lengths (Allen et al., 1987) and angles are within normal ranges. The cyano groups bond lengths C17—N4 [1.138 (3) Å] and C18—N3 [1.138 (3) Å] are in good agreement with the corresponding values [1.140 (2) and 1.142 (2) Å] reported in 4,5-diaminobenzene-1,2-dicarbonitrile (Zhang et al., 2009). Rings A (C1—C6), B (C7—C12) and C (N1/N2/C13—C16) are, of course, planar and they are oriented at dihedral angles of A/B = 49.47 (7), A/C = 48.08 (7) and B/C = 44.80 (7)°.

In the crystal structure, the π–π contact between the pyrazine and the phenyl rings, Cg1—Cg2i, [symmetry code: (i) 1/2 - x, 1/2 + y, 1/2 - z, where Cg1 and Cg2 are centroids of the rings C (N1/N2/C13—C16) and A (C1—C6), respectively] may stabilize the structure, with centroid-centroid distance of 3.813 (1) Å.

As can be seen from the packing diagram (Fig. 2), the molecules are stacked along the b axis and elongated along the a axis.

Related literature top

For applications of 2,3-dicyanopyrazine derivatives, see: Hou et al. (1993); Jaung et al. (1996); Takematsu et al. (1981). For a related structure, see: Zhang et al. (2009). For bond-length data, see: Allen et al. (1987).

Experimental top

For the preparation of the title compound, a mixture of benzyl (2.10 g, 10 mmol), diaminomaleonitrile (1.18 g, 11 mmol) and acetic acid (2 ml) in ethanol (20 ml) and water (15 ml) was heated at 348 K overnight. The reaction mixture was cooled, and water (20 ml) was added. The precipitate was filtered and washed with ethanol and then ether. The crude product was dissolved in dichloromethane and treated with activated charcoal. The solid was recrystallized from ethanol to give colorless crystals (yield; 1.97 g, 70%, m.p. 516–518 K).

Refinement top

H atoms were positioned geometrically, with C—H = 0.93 Å, and constrained to ride on their parent atom with Uiso(H) = 1.2Ueq(C).

Computing details top

Data collection: CrystalClear (Rigaku/MSC, 2005); cell refinement: CrystalClear (Rigaku/MSC, 2005); data reduction: CrystalClear (Rigaku/MSC, 2005); program(s) used to solve structure: SHELXS97 (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: WinGX (Farrugia, 1999) and PLATON (Spek, 2009).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title molecule with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.
[Figure 2] Fig. 2. A partial packing diagram.
5,6-Diphenylpyrazine-2,3-dicarbonitrile top
Crystal data top
C18H10N4F(000) = 584
Mr = 282.31Dx = 1.320 Mg m−3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 4324 reflections
a = 9.2195 (2) Åθ = 2.3–26.4°
b = 7.2837 (2) ŵ = 0.08 mm−1
c = 21.5507 (5) ÅT = 294 K
β = 101.108 (1)°Block, colorless
V = 1420.06 (6) Å30.30 × 0.15 × 0.10 mm
Z = 4
Data collection top
Rigaku R-AXIS RAPID-S
diffractometer		1708 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.137
graphiteθmax = 26.4°, θmin = 2.3°
ω scansh = −11→11
28933 measured reflectionsk = −9→8
2911 independent reflectionsl = −26→26
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.057H-atom parameters constrained
wR(F2) = 0.145 w = 1/[σ2(Fo2) + (0.0434P)2 + 0.1959P]
where P = (Fo2 + 2Fc2)/3
S = 1.05(Δ/σ)max < 0.001
2911 reflectionsΔρmax = 0.14 e Å−3
200 parametersΔρmin = −0.17 e Å−3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.039 (5)
Crystal data top
C18H10N4V = 1420.06 (6) Å3
Mr = 282.31Z = 4
Monoclinic, P21/nMo Kα radiation
a = 9.2195 (2) ŵ = 0.08 mm−1
b = 7.2837 (2) ÅT = 294 K
c = 21.5507 (5) Å0.30 × 0.15 × 0.10 mm
β = 101.108 (1)°
Data collection top
Rigaku R-AXIS RAPID-S
diffractometer		1708 reflections with I > 2σ(I)
28933 measured reflectionsRint = 0.137
2911 independent reflectionsθmax = 26.4°
Refinement top
R[F2 > 2σ(F2)] = 0.057H-atom parameters constrained
wR(F2) = 0.145Δρmax = 0.14 e Å−3
S = 1.05Δρmin = −0.17 e Å−3
2911 reflectionsAbsolute structure: ?
200 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
Special details top

Experimental. IR (Mattson 1000 F T—IR spectrophotometer, KBr, νmax): 3073 cm-1 (aromatic C—H), 2238 cm-1 (CN), 1515 cm-1 (CC). 1H-NMR (Bruker-Spectrospin Avance DPX 400 MHz Ultra-Shield): (δ, DMSO-d6) 7.40–7.50 p.p.m. (m, 10H, ArH).

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
N10.9159 (2)0.0899 (3)0.77849 (9)0.0548 (5)
N21.1240 (2)−0.0919 (3)0.72267 (8)0.0541 (5)
N31.1092 (3)0.1454 (3)0.92857 (11)0.0803 (7)
N41.4193 (3)−0.1142 (3)0.84155 (11)0.0843 (8)
C10.6099 (3)0.0462 (3)0.70896 (11)0.0558 (6)
H10.62120.00370.75030.067*
C20.4703 (3)0.0730 (3)0.67328 (13)0.0642 (7)
H20.38760.04460.69030.077*
C30.4526 (3)0.1412 (3)0.61287 (13)0.0677 (7)
H30.35820.15640.58880.081*
C40.5738 (3)0.1870 (4)0.58798 (12)0.0688 (7)
H40.56150.23780.54770.083*
C50.7134 (3)0.1579 (3)0.62258 (11)0.0617 (7)
H50.79540.18870.60540.074*
C60.7335 (2)0.0829 (3)0.68285 (10)0.0508 (6)
C70.9497 (3)−0.1528 (3)0.62762 (10)0.0517 (6)
C80.8195 (3)−0.2521 (3)0.60918 (11)0.0625 (7)
H80.7527−0.26150.63630.075*
C90.7894 (3)−0.3364 (4)0.55095 (13)0.0717 (7)
H90.7027−0.40350.53900.086*
C100.8868 (3)−0.3215 (4)0.51061 (12)0.0755 (8)
H100.8650−0.37650.47090.091*
C111.0169 (3)−0.2254 (4)0.52857 (12)0.0746 (8)
H111.0829−0.21630.50110.090*
C121.0494 (3)−0.1427 (3)0.58728 (11)0.0631 (7)
H121.1382−0.08030.59970.076*
C130.9860 (2)−0.0659 (3)0.69065 (10)0.0496 (6)
C140.8827 (2)0.0355 (3)0.71825 (10)0.0490 (5)
C151.1567 (2)−0.0300 (3)0.78196 (10)0.0526 (6)
C161.0523 (2)0.0551 (3)0.81061 (10)0.0521 (6)
C171.3043 (3)−0.0720 (3)0.81610 (11)0.0617 (7)
C181.0848 (3)0.1071 (3)0.87641 (12)0.0592 (6)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0558 (12)0.0556 (12)0.0531 (12)0.0020 (9)0.0111 (9)−0.0003 (9)
N20.0506 (12)0.0585 (12)0.0535 (12)0.0001 (9)0.0109 (9)0.0005 (9)
N30.0844 (17)0.0934 (18)0.0607 (14)0.0033 (13)0.0083 (12)−0.0100 (12)
N40.0646 (16)0.0988 (19)0.0842 (17)0.0087 (13)0.0009 (13)−0.0086 (13)
C10.0601 (15)0.0541 (14)0.0556 (14)0.0004 (12)0.0168 (11)−0.0013 (11)
C20.0530 (15)0.0619 (16)0.0793 (18)0.0008 (12)0.0171 (13)−0.0019 (13)
C30.0542 (16)0.0680 (17)0.0765 (18)0.0112 (12)0.0012 (13)0.0025 (14)
C40.0691 (18)0.0709 (17)0.0646 (16)0.0123 (14)0.0083 (14)0.0117 (13)
C50.0588 (16)0.0685 (17)0.0595 (15)0.0057 (12)0.0160 (12)0.0069 (12)
C60.0518 (14)0.0493 (13)0.0519 (13)0.0046 (10)0.0112 (10)−0.0019 (10)
C70.0533 (14)0.0545 (14)0.0472 (13)0.0067 (11)0.0096 (11)−0.0007 (10)
C80.0597 (15)0.0671 (17)0.0614 (15)0.0027 (13)0.0134 (12)−0.0081 (13)
C90.0681 (18)0.0721 (18)0.0709 (18)0.0028 (13)0.0032 (14)−0.0142 (14)
C100.088 (2)0.0764 (19)0.0560 (16)0.0228 (16)−0.0024 (15)−0.0127 (13)
C110.087 (2)0.083 (2)0.0592 (16)0.0206 (17)0.0273 (15)0.0004 (14)
C120.0651 (16)0.0658 (16)0.0602 (16)0.0054 (12)0.0167 (12)−0.0008 (12)
C130.0503 (13)0.0514 (14)0.0480 (13)−0.0014 (11)0.0118 (10)0.0014 (10)
C140.0489 (13)0.0492 (13)0.0500 (13)−0.0002 (10)0.0126 (10)0.0016 (10)
C150.0490 (13)0.0574 (14)0.0505 (14)−0.0016 (11)0.0072 (10)0.0011 (11)
C160.0556 (15)0.0526 (14)0.0476 (13)−0.0013 (11)0.0090 (11)−0.0002 (10)
C170.0594 (16)0.0664 (17)0.0586 (15)−0.0014 (13)0.0095 (13)−0.0045 (12)
C180.0599 (16)0.0619 (16)0.0559 (16)0.0034 (12)0.0111 (12)−0.0023 (12)
Geometric parameters (Å, °) top
N1—C141.335 (3)C7—C121.383 (3)
N1—C161.338 (3)C8—C91.376 (3)
N2—C131.339 (3)C8—H80.9300
N2—C151.334 (3)C9—C101.369 (4)
C1—C21.380 (3)C9—H90.9300
C1—H10.9300C10—C111.378 (4)
C2—H20.9300C10—H100.9300
C3—C41.371 (4)C11—H110.9300
C3—C21.374 (3)C12—C111.381 (3)
C3—H30.9300C12—H120.9300
C4—H40.9300C13—C71.477 (3)
C5—C41.374 (3)C14—C131.422 (3)
C5—H50.9300C15—C161.386 (3)
C6—C11.391 (3)C15—C171.450 (3)
C6—C51.388 (3)C17—N41.138 (3)
C6—C141.480 (3)C18—N31.138 (3)
C7—C81.393 (3)C18—C161.442 (3)
C14—N1—C16117.58 (19)C8—C9—H9119.9
C15—N2—C13117.57 (19)C10—C9—C8120.1 (3)
C2—C1—C6119.8 (2)C10—C9—H9119.9
C2—C1—H1120.1C9—C10—C11120.2 (2)
C6—C1—H1120.1C9—C10—H10119.9
C1—C2—H2119.8C11—C10—H10119.9
C3—C2—C1120.5 (2)C10—C11—C12120.1 (3)
C3—C2—H2119.8C10—C11—H11119.9
C2—C3—H3119.9C12—C11—H11119.9
C4—C3—C2120.1 (2)C7—C12—H12120.0
C4—C3—H3119.9C11—C12—C7120.0 (3)
C3—C4—C5119.9 (2)C11—C12—H12120.0
C3—C4—H4120.0N2—C13—C7115.93 (19)
C5—C4—H4120.0N2—C13—C14120.28 (19)
C4—C5—C6120.7 (2)C14—C13—C7123.8 (2)
C4—C5—H5119.6N1—C14—C6116.61 (19)
C6—C5—H5119.6N1—C14—C13120.96 (19)
C1—C6—C14120.0 (2)C13—C14—C6122.43 (19)
C5—C6—C1118.8 (2)N2—C15—C16122.0 (2)
C5—C6—C14121.2 (2)N2—C15—C17115.6 (2)
C8—C7—C13121.0 (2)C16—C15—C17122.2 (2)
C12—C7—C8119.2 (2)N1—C16—C15121.2 (2)
C12—C7—C13119.7 (2)N1—C16—C18117.1 (2)
C7—C8—H8119.9C15—C16—C18121.7 (2)
C9—C8—C7120.2 (2)N4—C17—C15176.3 (3)
C9—C8—H8119.9N3—C18—C16178.8 (3)
C16—N1—C14—C6−177.30 (19)C12—C7—C8—C9−1.2 (4)
C16—N1—C14—C133.9 (3)C13—C7—C8—C9−178.2 (2)
C14—N1—C16—C151.6 (3)C8—C7—C12—C112.2 (4)
C14—N1—C16—C18−177.3 (2)C13—C7—C12—C11179.3 (2)
C15—N2—C13—C144.2 (3)C7—C8—C9—C10−0.6 (4)
C15—N2—C13—C7−174.0 (2)C8—C9—C10—C111.4 (4)
C13—N2—C15—C161.3 (3)C9—C10—C11—C12−0.3 (4)
C13—N2—C15—C17176.1 (2)C7—C12—C11—C10−1.4 (4)
C6—C1—C2—C3−2.1 (4)N2—C13—C7—C12−43.6 (3)
C4—C3—C2—C1−1.4 (4)N2—C13—C7—C8133.4 (2)
C2—C3—C4—C52.6 (4)C14—C13—C7—C8−44.7 (3)
C6—C5—C4—C3−0.2 (4)C14—C13—C7—C12138.3 (2)
C5—C6—C1—C24.3 (3)N1—C14—C13—N2−7.0 (3)
C14—C6—C1—C2−173.3 (2)N1—C14—C13—C7171.0 (2)
C1—C6—C5—C4−3.2 (4)C6—C14—C13—N2174.2 (2)
C14—C6—C5—C4174.5 (2)C6—C14—C13—C7−7.8 (3)
C1—C6—C14—N1−49.0 (3)N2—C15—C16—N1−4.4 (4)
C1—C6—C14—C13129.8 (2)N2—C15—C16—C18174.4 (2)
C5—C6—C14—N1133.4 (2)C17—C15—C16—N1−178.9 (2)
C5—C6—C14—C13−47.8 (3)C17—C15—C16—C180.0 (4)
Acknowledgements top

The authors are indebted to the Department of Chemistry, Atatürk University, Erzurum, Turkey, for the use of X-ray diffractometer purchased under grant No. 2003/219 of the University Research Fund.

references
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