5,6-Diphenyl­pyrazine-2,3-dicarbonitrile

Hökelek, T.; Yalçın, E.; Seferoğlu, Z.; Şahin, E.

doi:10.1107/S1600536809033029

organic compounds

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ISSN: 2056-9890

Volume 65| Part 9| September 2009| Page o2225

doi:10.1107/S1600536809033029

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5,6-Diphenylpyrazine-2,3-dicarbonitrile

Tuncer Hökelek,^a ^* Ergin Yalçın,^b Zeynel Seferoğlu ^b and Ertan Şahin ^c

^aHacettepe University, Department of Physics, 06800 Beytepe, Ankara, Turkey, ^bGazi University, Department of Chemistry, 06500 Beşevler, Ankara, Turkey, and ^cAtatürk University, Department of Chemistry, 22240 Erzurum, Turkey
^*Correspondence e-mail: merzifon@hacettepe.edu.tr

(Received 18 August 2009; accepted 19 August 2009; online 22 August 2009)

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 π–π contacts between pyrazine and phenyl rings [centroid–centroid distance = 3.813 (1) Å] may stabilize the structure.

Related literature

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

Crystal data

C₁₈H₁₀N₄
M_r = 282.31
Monoclinic, P 2₁ /n
a = 9.2195 (2) Å
b = 7.2837 (2) Å
c = 21.5507 (5) Å
β = 101.108 (1)°
V = 1420.06 (6) Å³
Z = 4
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 294 K
0.30 × 0.15 × 0.10 mm

Data collection

Rigaku R-AXIS RAPID-S diffractometer
Absorption correction: none
28933 measured reflections
2911 independent reflections
1708 reflections with I > 2σ(I)
R_int = 0.137

Refinement

R[F² > 2σ(F²)] = 0.057
wR(F²) = 0.145
S = 1.05
2911 reflections
200 parameters
H-atom parameters constrained
Δρ_max = 0.14 e Å⁻³
Δρ_min = −0.18 e Å⁻³

Data collection: CrystalClear (Rigaku/MSC, 2005 ); cell refinement: CrystalClear; data reduction: CrystalClear; 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 ).

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809033029/xu2592sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809033029/xu2592Isup2.hkl

checkCIF report

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).

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

	Fig. 1. The molecular structure of the title molecule with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.
	Fig. 2. A partial packing diagram.

5,6-Diphenylpyrazine-2,3-dicarbonitrile top

Crystal data top

C₁₈H₁₀N₄	F(000) = 584
M_r = 282.31	D_x = 1.320 Mg m⁻³
Monoclinic, P2₁/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 4324 reflections
a = 9.2195 (2) Å	θ = 2.3–26.4°
b = 7.2837 (2) Å	µ = 0.08 mm⁻¹
c = 21.5507 (5) Å	T = 294 K
β = 101.108 (1)°	Block, colorless
V = 1420.06 (6) Å³	0.30 × 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 tube	R_int = 0.137
Graphite monochromator	θ_max = 26.4°, θ_min = 2.3°
ω scans	h = −11→11
28933 measured reflections	k = −9→8
2911 independent reflections	l = −26→26

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.057	H-atom parameters constrained
wR(F²) = 0.145	w = 1/[σ²(F_o²) + (0.0434P)² + 0.1959P] where P = (F_o² + 2F_c²)/3
S = 1.05	(Δ/σ)_max < 0.001
2911 reflections	Δρ_max = 0.14 e Å⁻³
200 parameters	Δρ_min = −0.18 e Å⁻³
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.039 (5)

Crystal data top

C₁₈H₁₀N₄	V = 1420.06 (6) Å³
M_r = 282.31	Z = 4
Monoclinic, P2₁/n	Mo Kα radiation
a = 9.2195 (2) Å	µ = 0.08 mm⁻¹
b = 7.2837 (2) Å	T = 294 K
c = 21.5507 (5) Å	0.30 × 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 reflections	R_int = 0.137
2911 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.057	0 restraints
wR(F²) = 0.145	H-atom parameters constrained
S = 1.05	Δρ_max = 0.14 e Å⁻³
2911 reflections	Δρ_min = −0.18 e Å⁻³
200 parameters

Special details top

Experimental. IR (Mattson 1000 F T—IR spectrophotometer, KBr, ν_max): 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

	x	y	z	U_iso*/U_eq
N1	0.9159 (2)	0.0899 (3)	0.77849 (9)	0.0548 (5)
N2	1.1240 (2)	−0.0919 (3)	0.72267 (8)	0.0541 (5)
N3	1.1092 (3)	0.1454 (3)	0.92857 (11)	0.0803 (7)
N4	1.4193 (3)	−0.1142 (3)	0.84155 (11)	0.0843 (8)
C1	0.6099 (3)	0.0462 (3)	0.70896 (11)	0.0558 (6)
H1	0.6212	0.0037	0.7503	0.067*
C2	0.4703 (3)	0.0730 (3)	0.67328 (13)	0.0642 (7)
H2	0.3876	0.0446	0.6903	0.077*
C3	0.4526 (3)	0.1412 (3)	0.61287 (13)	0.0677 (7)
H3	0.3582	0.1564	0.5888	0.081*
C4	0.5738 (3)	0.1870 (4)	0.58798 (12)	0.0688 (7)
H4	0.5615	0.2378	0.5477	0.083*
C5	0.7134 (3)	0.1579 (3)	0.62258 (11)	0.0617 (7)
H5	0.7954	0.1887	0.6054	0.074*
C6	0.7335 (2)	0.0829 (3)	0.68285 (10)	0.0508 (6)
C7	0.9497 (3)	−0.1528 (3)	0.62762 (10)	0.0517 (6)
C8	0.8195 (3)	−0.2521 (3)	0.60918 (11)	0.0625 (7)
H8	0.7527	−0.2615	0.6363	0.075*
C9	0.7894 (3)	−0.3364 (4)	0.55095 (13)	0.0717 (7)
H9	0.7027	−0.4035	0.5390	0.086*
C10	0.8868 (3)	−0.3215 (4)	0.51061 (12)	0.0755 (8)
H10	0.8650	−0.3765	0.4709	0.091*
C11	1.0169 (3)	−0.2254 (4)	0.52857 (12)	0.0746 (8)
H11	1.0829	−0.2163	0.5011	0.090*
C12	1.0494 (3)	−0.1427 (3)	0.58728 (11)	0.0631 (7)
H12	1.1382	−0.0803	0.5997	0.076*
C13	0.9860 (2)	−0.0659 (3)	0.69065 (10)	0.0496 (6)
C14	0.8827 (2)	0.0355 (3)	0.71825 (10)	0.0490 (5)
C15	1.1567 (2)	−0.0300 (3)	0.78196 (10)	0.0526 (6)
C16	1.0523 (2)	0.0551 (3)	0.81061 (10)	0.0521 (6)
C17	1.3043 (3)	−0.0720 (3)	0.81610 (11)	0.0617 (7)
C18	1.0848 (3)	0.1071 (3)	0.87641 (12)	0.0592 (6)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
N1	0.0558 (12)	0.0556 (12)	0.0531 (12)	0.0020 (9)	0.0111 (9)	−0.0003 (9)
N2	0.0506 (12)	0.0585 (12)	0.0535 (12)	0.0001 (9)	0.0109 (9)	0.0005 (9)
N3	0.0844 (17)	0.0934 (18)	0.0607 (14)	0.0033 (13)	0.0083 (12)	−0.0100 (12)
N4	0.0646 (16)	0.0988 (19)	0.0842 (17)	0.0087 (13)	0.0009 (13)	−0.0086 (13)
C1	0.0601 (15)	0.0541 (14)	0.0556 (14)	0.0004 (12)	0.0168 (11)	−0.0013 (11)
C2	0.0530 (15)	0.0619 (16)	0.0793 (18)	0.0008 (12)	0.0171 (13)	−0.0019 (13)
C3	0.0542 (16)	0.0680 (17)	0.0765 (18)	0.0112 (12)	0.0012 (13)	0.0025 (14)
C4	0.0691 (18)	0.0709 (17)	0.0646 (16)	0.0123 (14)	0.0083 (14)	0.0117 (13)
C5	0.0588 (16)	0.0685 (17)	0.0595 (15)	0.0057 (12)	0.0160 (12)	0.0069 (12)
C6	0.0518 (14)	0.0493 (13)	0.0519 (13)	0.0046 (10)	0.0112 (10)	−0.0019 (10)
C7	0.0533 (14)	0.0545 (14)	0.0472 (13)	0.0067 (11)	0.0096 (11)	−0.0007 (10)
C8	0.0597 (15)	0.0671 (17)	0.0614 (15)	0.0027 (13)	0.0134 (12)	−0.0081 (13)
C9	0.0681 (18)	0.0721 (18)	0.0709 (18)	0.0028 (13)	0.0032 (14)	−0.0142 (14)
C10	0.088 (2)	0.0764 (19)	0.0560 (16)	0.0228 (16)	−0.0024 (15)	−0.0127 (13)
C11	0.087 (2)	0.083 (2)	0.0592 (16)	0.0206 (17)	0.0273 (15)	0.0004 (14)
C12	0.0651 (16)	0.0658 (16)	0.0602 (16)	0.0054 (12)	0.0167 (12)	−0.0008 (12)
C13	0.0503 (13)	0.0514 (14)	0.0480 (13)	−0.0014 (11)	0.0118 (10)	0.0014 (10)
C14	0.0489 (13)	0.0492 (13)	0.0500 (13)	−0.0002 (10)	0.0126 (10)	0.0016 (10)
C15	0.0490 (13)	0.0574 (14)	0.0505 (14)	−0.0016 (11)	0.0072 (10)	0.0011 (11)
C16	0.0556 (15)	0.0526 (14)	0.0476 (13)	−0.0013 (11)	0.0090 (11)	−0.0002 (10)
C17	0.0594 (16)	0.0664 (17)	0.0586 (15)	−0.0014 (13)	0.0095 (13)	−0.0045 (12)
C18	0.0599 (16)	0.0619 (16)	0.0559 (16)	0.0034 (12)	0.0111 (12)	−0.0023 (12)

Geometric parameters (Å, º) top

N1—C14	1.335 (3)	C7—C12	1.383 (3)
N1—C16	1.338 (3)	C8—C9	1.376 (3)
N2—C13	1.339 (3)	C8—H8	0.9300
N2—C15	1.334 (3)	C9—C10	1.369 (4)
C1—C2	1.380 (3)	C9—H9	0.9300
C1—H1	0.9300	C10—C11	1.378 (4)
C2—H2	0.9300	C10—H10	0.9300
C3—C4	1.371 (4)	C11—H11	0.9300
C3—C2	1.374 (3)	C12—C11	1.381 (3)
C3—H3	0.9300	C12—H12	0.9300
C4—H4	0.9300	C13—C7	1.477 (3)
C5—C4	1.374 (3)	C14—C13	1.422 (3)
C5—H5	0.9300	C15—C16	1.386 (3)
C6—C1	1.391 (3)	C15—C17	1.450 (3)
C6—C5	1.388 (3)	C17—N4	1.138 (3)
C6—C14	1.480 (3)	C18—N3	1.138 (3)
C7—C8	1.393 (3)	C18—C16	1.442 (3)

C14—N1—C16	117.58 (19)	C8—C9—H9	119.9
C15—N2—C13	117.57 (19)	C10—C9—C8	120.1 (3)
C2—C1—C6	119.8 (2)	C10—C9—H9	119.9
C2—C1—H1	120.1	C9—C10—C11	120.2 (2)
C6—C1—H1	120.1	C9—C10—H10	119.9
C1—C2—H2	119.8	C11—C10—H10	119.9
C3—C2—C1	120.5 (2)	C10—C11—C12	120.1 (3)
C3—C2—H2	119.8	C10—C11—H11	119.9
C2—C3—H3	119.9	C12—C11—H11	119.9
C4—C3—C2	120.1 (2)	C7—C12—H12	120.0
C4—C3—H3	119.9	C11—C12—C7	120.0 (3)
C3—C4—C5	119.9 (2)	C11—C12—H12	120.0
C3—C4—H4	120.0	N2—C13—C7	115.93 (19)
C5—C4—H4	120.0	N2—C13—C14	120.28 (19)
C4—C5—C6	120.7 (2)	C14—C13—C7	123.8 (2)
C4—C5—H5	119.6	N1—C14—C6	116.61 (19)
C6—C5—H5	119.6	N1—C14—C13	120.96 (19)
C1—C6—C14	120.0 (2)	C13—C14—C6	122.43 (19)
C5—C6—C1	118.8 (2)	N2—C15—C16	122.0 (2)
C5—C6—C14	121.2 (2)	N2—C15—C17	115.6 (2)
C8—C7—C13	121.0 (2)	C16—C15—C17	122.2 (2)
C12—C7—C8	119.2 (2)	N1—C16—C15	121.2 (2)
C12—C7—C13	119.7 (2)	N1—C16—C18	117.1 (2)
C7—C8—H8	119.9	C15—C16—C18	121.7 (2)
C9—C8—C7	120.2 (2)	N4—C17—C15	176.3 (3)
C9—C8—H8	119.9	N3—C18—C16	178.8 (3)

C16—N1—C14—C6	−177.30 (19)	C12—C7—C8—C9	−1.2 (4)
C16—N1—C14—C13	3.9 (3)	C13—C7—C8—C9	−178.2 (2)
C14—N1—C16—C15	1.6 (3)	C8—C7—C12—C11	2.2 (4)
C14—N1—C16—C18	−177.3 (2)	C13—C7—C12—C11	179.3 (2)
C15—N2—C13—C14	4.2 (3)	C7—C8—C9—C10	−0.6 (4)
C15—N2—C13—C7	−174.0 (2)	C8—C9—C10—C11	1.4 (4)
C13—N2—C15—C16	1.3 (3)	C9—C10—C11—C12	−0.3 (4)
C13—N2—C15—C17	176.1 (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—C8	133.4 (2)
C2—C3—C4—C5	2.6 (4)	C14—C13—C7—C8	−44.7 (3)
C6—C5—C4—C3	−0.2 (4)	C14—C13—C7—C12	138.3 (2)
C5—C6—C1—C2	4.3 (3)	N1—C14—C13—N2	−7.0 (3)
C14—C6—C1—C2	−173.3 (2)	N1—C14—C13—C7	171.0 (2)
C1—C6—C5—C4	−3.2 (4)	C6—C14—C13—N2	174.2 (2)
C14—C6—C5—C4	174.5 (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—C13	129.8 (2)	N2—C15—C16—C18	174.4 (2)
C5—C6—C14—N1	133.4 (2)	C17—C15—C16—N1	−178.9 (2)
C5—C6—C14—C13	−47.8 (3)	C17—C15—C16—C18	0.0 (4)

Experimental details

Crystal data
Chemical formula	C₁₈H₁₀N₄
M_r	282.31
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	294
a, b, c (Å)	9.2195 (2), 7.2837 (2), 21.5507 (5)
β (°)	101.108 (1)
V (Å³)	1420.06 (6)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.08
Crystal size (mm)	0.30 × 0.15 × 0.10

Data collection
Diffractometer	Rigaku R-AXIS RAPID-S diffractometer
Absorption correction	–
No. of measured, independent and observed [I > 2σ(I)] reflections	28933, 2911, 1708
R_int	0.137
(sin θ/λ)_max (Å⁻¹)	0.626

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.057, 0.145, 1.05
No. of reflections	2911
No. of parameters	200
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.14, −0.18

Computer programs: CrystalClear (Rigaku/MSC, 2005), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997), WinGX (Farrugia, 1999) and PLATON (Spek, 2009).

Acknowledgements

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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