5,6-Di-2-thienyl-2,3-dihydro­pyrazine

Abstract

In the title compound, C₁₂H₁₀N₂S₂, which was synthesized by the reaction of 2,2′-thenil and ethyl­enediamine, the dihedral angle between the two thio­phene rings is 66.33 (9)°. In the crystal structure, inter­molecular C—H⋯N hydrogen bonds link the mol­ecules into infinite chains along the b axis and weak C—H⋯π inter­actions may further stabilize the structure.

Related literature

For backgroud to thenils, see: Shimon et al. (1993 ▶). For related structures, see: Crundwell et al. (2002a ▶,b ▶, 2003 ▶); Linehan et al. (2003 ▶); Stacy et al. (2003 ▶). For bond-length data, see: Allen et al. (1987 ▶). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986 ▶).

Experimental

Crystal data

• C₁₂H₁₀N₂S₂

• M _r = 246.34

• Monoclinic,

• a = 5.5006 (9) Å

• b = 7.5246 (12) Å

• c = 14.116 (2) Å

• β = 97.902 (5)°

• V = 578.73 (16) ų

• Z = 2

• Mo Kα radiation

• μ = 0.43 mm⁻¹

• T = 100 K

• 0.32 × 0.26 × 0.08 mm

Data collection

• Bruker APEX DUO CCD area-detector diffractometer

• Absorption correction: multi-scan (SADABS; Bruker, 2009 ▶) T _min = 0.875, T _max = 0.965

• 9583 measured reflections

• 4603 independent reflections

• 4295 reflections with I > 2σ(I)

• R _int = 0.022

Refinement

• R[F ² > 2σ(F ²)] = 0.032

• wR(F ²) = 0.115

• S = 1.20

• 4603 reflections

• 145 parameters

• 1 restraint

• All H-atom parameters refined

• Δρ_max = 0.62 e Å⁻³

• Δρ_min = −0.47 e Å⁻³

• Absolute structure: Flack (1983 ▶), with 1899 Friedel pairs

• Flack parameter: 0.07 (6)

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: SAINT (Bruker, 2009 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 ▶).

Supplementary Material

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

Table 1. Hydrogen-bond geometry (Å, °).

Cg2 is the centroid of the S2/C9–C12 ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C1—H1A⋯N1i	0.93	2.33	3.235 (3)	163
C2—H2A⋯Cg2ii	0.93	2.85	3.7737 (18)	171

Symmetry codes: (i) ; (ii) .

supplementary crystallographic information

Comment

Thienyl-based guests have shown preferential inclusion into the host by keeping thienyl ring S atoms pointed away from the face of growing crystals, possibly to avoid unfavorable electrostatic interactions between sulfur lone pairs coplanar with the thiophene ring and molecules already incorporated into the growing crystal face (Shimon et al., 1993). The structural studies on thenoins (Crundwell et al., 2002a,b) and thenils (Crundwell et al., 2003), and other thiophene-containing molecules such as 2,5-diphenyl-3,4-dithien-3-ylcyclopentadien-1-one (Linehan et al., 2003) and 4-bromo-2-thiophenecarboxaldehyde (Stacy et al., 2003) have been reported in the literature. In continuation of this area of study, the crystal structure of the title compound, (I), is reported here.

In the molecule of the title compound (Fig. 1), the bond lengths (Allen et al., 1987) and angles are within normal ranges. The dihedral angle between the two thiophene rings S1/C1–C4 and S2/C9–C12 is 66.33 (9)°. In the crystal structure, intermolecular C—H···N hydrogen bonds (Table 1) link the molecules (Fig. 2) into infinite chains along the b axis, in which they may be effective in the stabilization of the structure. The crystal structure is further stabilized by C—H···π interactions (Table 1), involving the S2/C9–C12 (centroid Cg2) ring.

Experimental

2,2'-thenil (55 mg) and ethylenediamine (15 mg) in ethanol/water (40 ml) were heated under reflux for 2 h with stirring. The resulting solution was then cooled to room temperature. After a few days of slow evaporation of the solvent, brown plates of (I) were obtained.

Refinement

All H atoms were positioned geometrically (C—H = 0.93 or 0.97 Å) and were refined using a riding model, with U_iso(H) = 1.2 or 1.5U_eq(C). In the absence of significant anomalous scattering effects, 1899 Friedel pairs were merged.

Figures

Fig. 1.

The asymmetric unit of (I) with displacement ellipsoids drawn at the 50% probability level.

Fig. 2.

The crystal packing of (I), showing hydrogen-bonded (dashed lines) networks. H atoms are not involving the hydrogen bond interactions are omitted for clarity.

Crystal data

C12H10N2S2	F(000) = 256
Mr = 246.34	Dx = 1.414 Mg m−3
Monoclinic, P21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2yb	Cell parameters from 5014 reflections
a = 5.5006 (9) Å	θ = 2.9–34.8°
b = 7.5246 (12) Å	µ = 0.43 mm−1
c = 14.116 (2) Å	T = 100 K
β = 97.902 (5)°	Plate, brown
V = 578.73 (16) Å3	0.32 × 0.26 × 0.08 mm
Z = 2

Data collection

Bruker APEX DUO CCD area-detector diffractometer	4603 independent reflections
Radiation source: fine-focus sealed tube	4295 reflections with I > 2σ(I)
graphite	Rint = 0.022
φ and ω scans	θmax = 35.1°, θmin = 1.5°
Absorption correction: multi-scan (SADABS; Bruker, 2009)	h = −8→8
Tmin = 0.875, Tmax = 0.965	k = −12→12
9583 measured reflections	l = −22→22

Refinement

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)] = 0.032	All H-atom parameters refined
wR(F2) = 0.115	w = 1/[σ2(Fo2) + (0.0632P)2 + 0.0559P] where P = (Fo2 + 2Fc2)/3
S = 1.20	(Δ/σ)max < 0.001
4603 reflections	Δρmax = 0.62 e Å−3
145 parameters	Δρmin = −0.47 e Å−3
1 restraint	Absolute structure: Flack (1983), with 1899 Friedel pairs
Primary atom site location: structure-invariant direct methods	Flack parameter: 0.07 (6)

Special details

Experimental. The crystal was placed in the cold stream of an Oxford Cryosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) K.

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 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 (Ų)

	x	y	z	Uiso*/Ueq
S1	0.53730 (6)	0.88379 (6)	0.15567 (3)	0.02249 (9)
S2	−0.08370 (7)	0.37500 (7)	0.39261 (3)	0.02435 (10)
N1	−0.1511 (2)	0.42753 (19)	0.18646 (9)	0.0176 (2)
N2	0.2016 (2)	0.58341 (19)	0.08083 (8)	0.0167 (2)
C1	0.5372 (3)	1.0745 (3)	0.22117 (12)	0.0256 (3)
H1A	0.6518	1.1651	0.2206	0.031*
C2	0.3468 (3)	1.0777 (2)	0.27490 (12)	0.0225 (3)
H2A	0.3166	1.1719	0.3143	0.027*
C3	0.2025 (3)	0.9222 (2)	0.26367 (10)	0.0176 (2)
H3A	0.0665	0.9026	0.2948	0.021*
C4	0.2854 (2)	0.8021 (2)	0.20133 (9)	0.0141 (2)
C5	0.1765 (2)	0.6334 (2)	0.16622 (10)	0.0141 (2)
C6	0.0602 (3)	0.4259 (2)	0.04601 (10)	0.0199 (3)
H6A	0.1494	0.3194	0.0686	0.024*
H6B	0.0373	0.4245	−0.0234	0.024*
C7	−0.1875 (3)	0.4280 (2)	0.08163 (10)	0.0192 (3)
H7A	−0.2783	0.5333	0.0582	0.023*
H7B	−0.2817	0.3244	0.0579	0.023*
C8	0.0286 (2)	0.5231 (2)	0.22635 (9)	0.0136 (2)
C9	0.0980 (3)	0.5061 (2)	0.32993 (9)	0.0148 (2)
C10	0.3080 (3)	0.5582 (2)	0.38767 (10)	0.0199 (3)
H10A	0.4286	0.6292	0.3670	0.024*
C11	0.3203 (4)	0.4914 (3)	0.48252 (11)	0.0272 (3)
H11A	0.4496	0.5144	0.5307	0.033*
C12	0.1220 (4)	0.3904 (3)	0.49497 (11)	0.0296 (4)
H12A	0.1007	0.3360	0.5524	0.036*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
S1	0.02124 (15)	0.02353 (19)	0.02375 (16)	−0.01080 (15)	0.00690 (12)	−0.00227 (15)
S2	0.02570 (17)	0.0293 (2)	0.01976 (15)	−0.00416 (17)	0.00917 (12)	0.00490 (16)
N1	0.0195 (5)	0.0164 (5)	0.0168 (4)	−0.0061 (4)	0.0022 (4)	−0.0014 (4)
N2	0.0188 (5)	0.0166 (5)	0.0151 (5)	−0.0038 (4)	0.0037 (4)	−0.0023 (4)
C1	0.0311 (8)	0.0176 (7)	0.0264 (7)	−0.0130 (6)	−0.0022 (6)	0.0022 (6)
C2	0.0283 (7)	0.0127 (6)	0.0246 (6)	−0.0012 (6)	−0.0030 (5)	−0.0006 (5)
C3	0.0178 (5)	0.0161 (6)	0.0186 (5)	−0.0030 (5)	0.0010 (4)	−0.0018 (5)
C4	0.0142 (5)	0.0126 (6)	0.0151 (5)	−0.0027 (4)	0.0007 (4)	0.0008 (4)
C5	0.0138 (5)	0.0131 (6)	0.0154 (5)	−0.0023 (4)	0.0019 (4)	0.0006 (4)
C6	0.0256 (6)	0.0162 (6)	0.0181 (5)	−0.0039 (5)	0.0042 (5)	−0.0054 (5)
C7	0.0203 (6)	0.0200 (7)	0.0164 (5)	−0.0066 (5)	0.0001 (4)	−0.0024 (5)
C8	0.0154 (5)	0.0113 (5)	0.0141 (5)	−0.0022 (4)	0.0027 (4)	0.0000 (4)
C9	0.0180 (5)	0.0129 (6)	0.0140 (5)	−0.0001 (5)	0.0036 (4)	0.0004 (4)
C10	0.0205 (6)	0.0206 (7)	0.0173 (5)	−0.0006 (5)	−0.0017 (5)	0.0012 (5)
C11	0.0331 (8)	0.0304 (9)	0.0163 (6)	0.0034 (7)	−0.0030 (5)	0.0006 (6)
C12	0.0399 (8)	0.0353 (10)	0.0151 (5)	0.0070 (9)	0.0087 (5)	0.0054 (7)

Geometric parameters (Å, °)

S1—C1	1.707 (2)	C4—C5	1.461 (2)
S1—C4	1.7201 (14)	C5—C8	1.5040 (19)
S2—C12	1.7124 (19)	C6—C7	1.516 (2)
S2—C9	1.7317 (14)	C6—H6A	0.9700
N1—C8	1.2874 (18)	C6—H6B	0.9700
N1—C7	1.4658 (19)	C7—H7A	0.9700
N2—C5	1.2880 (18)	C7—H7B	0.9700
N2—C6	1.465 (2)	C8—C9	1.4652 (19)
C1—C2	1.375 (3)	C9—C10	1.376 (2)
C1—H1A	0.9300	C10—C11	1.423 (2)
C2—C3	1.411 (2)	C10—H10A	0.9300
C2—H2A	0.9300	C11—C12	1.361 (3)
C3—C4	1.382 (2)	C11—H11A	0.9300
C3—H3A	0.9300	C12—H12A	0.9300
C1—S1—C4	92.13 (8)	C7—C6—H6B	109.7
C12—S2—C9	91.82 (8)	H6A—C6—H6B	108.2
C8—N1—C7	115.50 (12)	N1—C7—C6	109.29 (12)
C5—N2—C6	115.48 (12)	N1—C7—H7A	109.8
C2—C1—S1	111.76 (12)	C6—C7—H7A	109.8
C2—C1—H1A	124.1	N1—C7—H7B	109.8
S1—C1—H1A	124.1	C6—C7—H7B	109.8
C1—C2—C3	112.51 (15)	H7A—C7—H7B	108.3
C1—C2—H2A	123.7	N1—C8—C9	117.84 (12)
C3—C2—H2A	123.7	N1—C8—C5	120.25 (12)
C4—C3—C2	112.59 (13)	C9—C8—C5	121.61 (12)
C4—C3—H3A	123.7	C10—C9—C8	130.47 (13)
C2—C3—H3A	123.7	C10—C9—S2	110.85 (10)
C3—C4—C5	128.94 (12)	C8—C9—S2	118.02 (10)
C3—C4—S1	110.99 (11)	C9—C10—C11	112.61 (15)
C5—C4—S1	119.83 (10)	C9—C10—H10A	123.7
N2—C5—C4	118.67 (13)	C11—C10—H10A	123.7
N2—C5—C8	120.18 (13)	C12—C11—C10	112.55 (15)
C4—C5—C8	121.10 (11)	C12—C11—H11A	123.7
N2—C6—C7	109.89 (12)	C10—C11—H11A	123.7
N2—C6—H6A	109.7	C11—C12—S2	112.16 (12)
C7—C6—H6A	109.7	C11—C12—H12A	123.9
N2—C6—H6B	109.7	S2—C12—H12A	123.9
C4—S1—C1—C2	−1.31 (14)	C7—N1—C8—C5	3.3 (2)
S1—C1—C2—C3	0.95 (19)	N2—C5—C8—N1	−29.3 (2)
C1—C2—C3—C4	0.1 (2)	C4—C5—C8—N1	148.07 (15)
C2—C3—C4—C5	−175.19 (14)	N2—C5—C8—C9	144.36 (15)
C2—C3—C4—S1	−1.03 (16)	C4—C5—C8—C9	−38.3 (2)
C1—S1—C4—C3	1.33 (12)	N1—C8—C9—C10	163.90 (16)
C1—S1—C4—C5	176.10 (12)	C5—C8—C9—C10	−9.9 (2)
C6—N2—C5—C4	−172.06 (13)	N1—C8—C9—S2	−5.87 (19)
C6—N2—C5—C8	5.4 (2)	C5—C8—C9—S2	−179.66 (11)
C3—C4—C5—N2	147.03 (16)	C12—S2—C9—C10	−0.12 (14)
S1—C4—C5—N2	−26.69 (19)	C12—S2—C9—C8	171.56 (13)
C3—C4—C5—C8	−30.4 (2)	C8—C9—C10—C11	−170.37 (16)
S1—C4—C5—C8	155.92 (11)	S2—C9—C10—C11	−0.03 (18)
C5—N2—C6—C7	37.17 (19)	C9—C10—C11—C12	0.2 (2)
C8—N1—C7—C6	38.97 (19)	C10—C11—C12—S2	−0.3 (2)
N2—C6—C7—N1	−60.13 (17)	C9—S2—C12—C11	0.26 (17)
C7—N1—C8—C9	−170.61 (13)

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
C1—H1A···N1i	0.93	2.33	3.235 (3)	163
C2—H2A···Cg2ii	0.93	2.85	3.7737 (18)	171

Symmetry codes: (i) x+1, y+1, z; (ii) x, y+1, z.