trans-2-(2-Phenyl­ethenyl)­pyrazine

The title compound, C₁₂H₁₀N₂, belonging to the orthorhombic system with space group Pbca, was prepared by the condensation reaction of benz­aldehyde and 2-methyl­pyrazine in DMF, using KOH as catalyst. The mol­ecule is nearly planar, with a dihedral angle of 7.1 (3)° between the pyrazine and phenyl planes. In the crystal structure, mol­ecules are connected by C—H...N hydrogen bonds and weak π–π interactions, resulting in a two-dimensional network.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.045
• wR factor = 0.103
• Data-to-parameter ratio = 13.5

checkCIF/PLATON results

No syntax errors found


No errors found in this datablock

---

Computing details

Data collection: SMART (Bruker, 1997); cell refinement: SMART; data reduction: SAINT (Bruker, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 1997); software used to prepare material for publication: SHELXTL.

trans-2-(2-Phenylethenyl)pyrazine

Crystal data

C12H10N2	Dx = 1.242 Mg m^−3
Mr = 182.22	Melting point: 355 K
Orthorhombic, Pbca	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2ab	Cell parameters from 785 reflections
a = 9.794 (5) Å	θ = 3.5–23.7°
b = 7.388 (3) Å	µ = 0.08 mm^−1
c = 26.946 (12) Å	T = 293 K
V = 1949.6 (15) Å^3	Plate, colourless
Z = 8	0.24 × 0.20 × 0.08 mm
F(000) = 768

Data collection

Bruker SMART CCD area-detector diffractometer	1724 independent reflections
Radiation source: fine-focus sealed tube	1201 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.040
ψ and ω scans	θmax = 25.0°, θmin = 2.6°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −11→11
Tmin = 0.954, Tmax = 0.994	k = −8→8
9258 measured reflections	l = −22→32

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.045	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.103	H-atom parameters constrained
S = 1.09	w = 1/[σ^2(Fo^2) + (0.03P)^2 + 0.5088P] where P = (Fo^2 + 2Fc^2)/3
1724 reflections	(Δ/σ)max < 0.001
128 parameters	Δρmax = 0.13 e Å^−3
0 restraints	Δρmin = −0.10 e Å^−3

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
N1	0.38022 (15)	−0.0078 (2)	0.43674 (6)	0.0598 (5)
N2	0.56948 (18)	−0.2812 (2)	0.45665 (6)	0.0710 (5)
C1	0.50626 (18)	−0.0023 (2)	0.41776 (7)	0.0500 (5)
C2	0.5984 (2)	−0.1396 (3)	0.42815 (7)	0.0649 (6)
H2	0.6853	−0.1322	0.4144	0.078*
C3	0.4446 (2)	−0.2835 (3)	0.47528 (7)	0.0669 (6)
H3	0.4188	−0.3791	0.4957	0.080*
C4	0.3520 (2)	−0.1491 (3)	0.46537 (7)	0.0665 (6)
H4	0.2654	−0.1573	0.4794	0.080*
C5	0.54309 (19)	0.1496 (3)	0.38608 (7)	0.0552 (5)
H5	0.6268	0.1447	0.3699	0.066*
C6	0.46610 (18)	0.2940 (2)	0.37869 (6)	0.0538 (5)
H6	0.3838	0.2972	0.3959	0.065*
C7	0.49472 (18)	0.4493 (2)	0.34674 (7)	0.0493 (5)
C8	0.3985 (2)	0.5870 (3)	0.34227 (7)	0.0605 (5)
H8	0.3178	0.5803	0.3603	0.073*
C9	0.4209 (2)	0.7334 (3)	0.31156 (8)	0.0722 (6)
H9	0.3554	0.8240	0.3091	0.087*
C10	0.5392 (2)	0.7458 (3)	0.28467 (8)	0.0730 (6)
H10	0.5541	0.8442	0.2638	0.088*
C11	0.6357 (2)	0.6119 (3)	0.28872 (7)	0.0698 (6)
H11	0.7161	0.6197	0.2705	0.084*
C12	0.61442 (19)	0.4660 (3)	0.31958 (7)	0.0592 (5)
H12	0.6814	0.3773	0.3223	0.071*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.0556 (10)	0.0566 (10)	0.0673 (10)	−0.0005 (8)	0.0050 (8)	0.0071 (8)
N2	0.0723 (12)	0.0663 (12)	0.0743 (12)	0.0081 (9)	−0.0121 (10)	0.0099 (10)
C1	0.0498 (11)	0.0478 (11)	0.0523 (10)	−0.0012 (9)	−0.0042 (8)	−0.0032 (9)
C2	0.0560 (12)	0.0670 (14)	0.0718 (14)	0.0057 (10)	−0.0011 (10)	0.0064 (11)
C3	0.0772 (15)	0.0586 (13)	0.0648 (13)	−0.0049 (11)	−0.0094 (12)	0.0116 (11)
C4	0.0622 (13)	0.0649 (14)	0.0724 (14)	−0.0056 (11)	0.0042 (10)	0.0095 (12)
C5	0.0488 (10)	0.0578 (12)	0.0592 (12)	−0.0021 (10)	0.0051 (9)	−0.0015 (10)
C6	0.0482 (11)	0.0547 (12)	0.0584 (12)	−0.0028 (9)	0.0017 (9)	−0.0008 (10)
C7	0.0504 (11)	0.0492 (11)	0.0484 (10)	−0.0048 (9)	−0.0060 (9)	−0.0046 (9)
C8	0.0565 (12)	0.0599 (12)	0.0651 (12)	−0.0009 (10)	−0.0038 (10)	−0.0010 (10)
C9	0.0769 (15)	0.0597 (13)	0.0799 (14)	0.0004 (11)	−0.0191 (12)	0.0079 (12)
C10	0.0867 (16)	0.0644 (15)	0.0679 (14)	−0.0184 (13)	−0.0159 (13)	0.0141 (11)
C11	0.0721 (14)	0.0722 (15)	0.0652 (13)	−0.0182 (12)	0.0035 (11)	0.0000 (11)
C12	0.0583 (12)	0.0551 (12)	0.0642 (12)	−0.0042 (10)	0.0012 (10)	−0.0018 (10)

Geometric parameters (Å, º)

N1—C4	1.327 (2)	C6—H6	0.9300
N1—C1	1.337 (2)	C7—C12	1.387 (2)
N2—C3	1.322 (3)	C7—C8	1.392 (3)
N2—C2	1.329 (2)	C8—C9	1.379 (3)
C1—C2	1.386 (3)	C8—H8	0.9300
C1—C5	1.455 (2)	C9—C10	1.370 (3)
C2—H2	0.9300	C9—H9	0.9300
C3—C4	1.371 (3)	C10—C11	1.372 (3)
C3—H3	0.9300	C10—H10	0.9300
C4—H4	0.9300	C11—C12	1.377 (3)
C5—C6	1.321 (2)	C11—H11	0.9300
C5—H5	0.9300	C12—H12	0.9300
C6—C7	1.461 (2)
C4—N1—C1	116.01 (16)	C7—C6—H6	116.1
C3—N2—C2	115.27 (18)	C12—C7—C8	117.46 (18)
N1—C1—C2	120.11 (17)	C12—C7—C6	122.86 (17)
N1—C1—C5	118.46 (16)	C8—C7—C6	119.68 (17)
C2—C1—C5	121.42 (17)	C9—C8—C7	121.17 (19)
N2—C2—C1	123.65 (19)	C9—C8—H8	119.4
N2—C2—H2	118.2	C7—C8—H8	119.4
C1—C2—H2	118.2	C10—C9—C8	120.3 (2)
N2—C3—C4	121.9 (2)	C10—C9—H9	119.9
N2—C3—H3	119.0	C8—C9—H9	119.9
C4—C3—H3	119.0	C9—C10—C11	119.5 (2)
N1—C4—C3	123.04 (19)	C9—C10—H10	120.3
N1—C4—H4	118.5	C11—C10—H10	120.3
C3—C4—H4	118.5	C10—C11—C12	120.5 (2)
C6—C5—C1	124.71 (17)	C10—C11—H11	119.7
C6—C5—H5	117.6	C12—C11—H11	119.7
C1—C5—H5	117.6	C11—C12—C7	121.07 (19)
C5—C6—C7	127.80 (17)	C11—C12—H12	119.5
C5—C6—H6	116.1	C7—C12—H12	119.5
C4—N1—C1—C2	0.3 (3)	C5—C6—C7—C12	−1.4 (3)
C4—N1—C1—C5	−179.97 (16)	C5—C6—C7—C8	177.73 (19)
C3—N2—C2—C1	−0.3 (3)	C12—C7—C8—C9	0.7 (3)
N1—C1—C2—N2	−0.1 (3)	C6—C7—C8—C9	−178.48 (17)
C5—C1—C2—N2	−179.74 (17)	C7—C8—C9—C10	0.0 (3)
C2—N2—C3—C4	0.4 (3)	C8—C9—C10—C11	−0.3 (3)
C1—N1—C4—C3	−0.3 (3)	C9—C10—C11—C12	−0.1 (3)
N2—C3—C4—N1	−0.1 (3)	C10—C11—C12—C7	0.9 (3)
N1—C1—C5—C6	7.7 (3)	C8—C7—C12—C11	−1.2 (3)
C2—C1—C5—C6	−172.66 (19)	C6—C7—C12—C11	177.98 (17)
C1—C5—C6—C7	−178.54 (17)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C4—H4···N2^i	0.93	2.62	3.512 (3)	161

Symmetry code: (i) x−1/2, −y−1/2, −z+1.