7-Aza­thieno[2,3-c]cinnoline

The title compound (systematic name: pyrido[4,3-e]thieno[2,3-c]pyridazine), C₉H₅N₃S, consists of three fused heterocyclic rings. The mol­ecule is planar and the N=N bond length of 1.302 (2) Å is in good agreement with values observed in similar compounds. The mol­ecules show π–π stacking inter­actions, forming mol­ecular stacks along the b axis with inter­planar distances of 3.39 (2) and 3.49 (2) Å. The C—H groups of the thio­phene ring are involved in C—H...N inter­actions, joining mol­ecules into two-dimensional sheets parallel to (01).

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.041
• wR factor = 0.132
• Data-to-parameter ratio = 17.3

checkCIF/PLATON results

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Alert level G
PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature        293 K

   0 ALERT level A = In general: serious problem
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   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
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S1. Comment

The crystal structure of the title compound was solved as part of a study of new tris-heterocyclic compounds with potential biological activity (Stockmann & Fiksdahl, 2007). Thieno[c]cinnolines (Barton et al., 1985) have been described in the literature and the crystal structure of benzo[c]cinnoline (9,10-diazaphenanthrene) has been solved (van der Meer et al., 1972). A view of the title molecule with the atomic numbering scheme is presented in Fig. 1. The bond lengths are within the normal range of such bonds and also in accordance with the regio-isomer 7-azathieno[3,2-c]cinnoline (Hansen et al., 2007) and other benzo[c]cinnoline derivatives (Hökelek et al., 1990, 1991a,b). The mean N═N distance for seven similar structures is 1.293 (10) Å, ranging from 1.283 (4) to 1.306 (2) Å. The C6—C7 bonds are always significantly shorter than the C7—C8 bonds. Mean C6—C7 bond is 1.364 (10) Å while the mean C7—C8 bond is 1.409 (10) Å. Also the angles show the same systematic differences. The mean C8—C9—C3 angle and the mean C4—C8—C9 angle are 117.8(2.) and 116.1(1.9)°, respectively, while the mean N2—C4—C8 angle is 122.3(2.0)° (see van der Meer, 1972 and references cited therein). The C—H groups of the thiophene ring are involved in intermolecular C—H···N interactions.

Related literature

For related literature, see: Barton et al. (1985); Hansen et al. (2007); Holt & Fiksdahl (2006); Hökelek et al. (1990, 1991a,b); Stockmann & Fiksdahl (2007); van der Meer et al. (1972).

S2. Experimental

7-Azathieno[2,3-c]cinnoline was prepared by intramolecular diazo coupling of the diazonium ion intermediate, made by NOBF₄ diazotization (Holt & Fiksdahl, 2006) of the 3-amino-4-(thiophen-3-yl)pyridine precursor. Single crystals were grown by crystallization from ethyl acetate (Stockmann & Fiksdahl, 2007).

S3. Refinement

All H atoms were found from a difference map and were refined with isotropic displacement parameters.

Computing details

Data collection: CAD-4-PC Software (Enraf–Nonius, 1992); cell refinement: CELDIM in CAD-4-PC Software (Enraf–Nonius, 1992); data reduction: XCAD (McArdle & Higgins, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEX (McArdle, 1995) and ORTEPIII (Burnett & Johnson, 1996); software used to prepare material for publication: OSCAIL (McArdle, 1993).

Figures

Fig. 1. A view of the title molecule with the atomic numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.

pyrido[4,3-e]thieno[2,3-c]pyridazine

Crystal data

C9H5N3S	Z = 2
Mr = 187.22	F(000) = 192
Triclinic, P1	Dx = 1.514 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71069 Å
a = 6.8340 (18) Å	Cell parameters from 25 reflections
b = 7.656 (2) Å	θ = 12–18°
c = 8.847 (2) Å	µ = 0.34 mm^−1
α = 104.172 (3)°	T = 293 K
β = 101.376 (4)°	Prism, colourless
γ = 107.042 (5)°	0.40 × 0.30 × 0.20 mm
V = 410.63 (18) Å^3

Data collection

Enraf–Nonius CAD-4 diffractometer	1805 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.008
Graphite monochromator	θmax = 29.9°, θmin = 2.5°
ω/2θ scans	h = 0→9
Absorption correction: ψ scan [ABSCALC in OSCAIL (McArdle & Daly, 1999; North et al., 1968)]	k = −10→10
Tmin = 0.882, Tmax = 0.935	l = −12→12
2646 measured reflections	3 standard reflections every 120 min
2387 independent reflections	intensity decay: 1%

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)] = 0.041	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.132	All H-atom parameters refined
S = 1.09	w = 1/[σ^2(Fo^2) + (0.0802P)^2 + 0.041P] where P = (Fo^2 + 2Fc^2)/3
2387 reflections	(Δ/σ)max = 0.016
138 parameters	Δρmax = 0.37 e Å^−3
0 restraints	Δρmin = −0.28 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.

Least-squares planes (x,y,z in crystal coordinates) and deviations from them (* indicates atom used to define plane)

- 0.8879 (0.0025) x + 6.8684 (0.0030) y - 5.7312 (0.0029) z = 1.8667 (0.0014)

* 0.0357 (0.0008) S1 * -0.0053 (0.0012) N1 * -0.0173 (0.0012) N2 * 0.0186 (0.0014) N3 * 0.0049 (0.0013) C1 * -0.0149 (0.0013) C2 * 0.0030 (0.0013) C3 * -0.0112 (0.0013) C4 * 0.0111 (0.0015) C5 * 0.0122 (0.0014) C6 * -0.0038 (0.0013) C7 * -0.0169 (0.0012) C8 * -0.0161 (0.0012) C9

Rms deviation of fitted atoms = 0.0156

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
S1	0.31663 (8)	0.41015 (6)	0.11053 (5)	0.05756 (17)
N2	0.78580 (19)	0.7761 (2)	0.48565 (19)	0.0527 (3)
N1	0.6832 (2)	0.6459 (2)	0.34347 (19)	0.0516 (3)
N3	0.7020 (3)	1.0644 (2)	0.83784 (19)	0.0640 (4)
H2	0.009 (3)	0.557 (3)	0.340 (3)	0.064 (6)*
H5	0.937 (4)	1.042 (3)	0.766 (3)	0.071 (6)*
H6	0.419 (4)	1.059 (4)	0.871 (3)	0.083 (7)*
H7	0.203 (4)	0.833 (4)	0.648 (3)	0.084 (7)*
H1	−0.045 (3)	0.332 (3)	0.077 (2)	0.057 (5)*
C1	0.0860 (3)	0.4135 (2)	0.1556 (2)	0.0521 (4)
C2	0.1168 (2)	0.5381 (2)	0.30372 (18)	0.0440 (3)
C3	0.4669 (2)	0.5808 (2)	0.29745 (17)	0.0400 (3)
C4	0.6725 (2)	0.8437 (2)	0.58315 (18)	0.0421 (3)
C5	0.7900 (3)	0.9894 (3)	0.7357 (2)	0.0584 (4)
C6	0.4846 (3)	1.0005 (3)	0.7961 (2)	0.0576 (4)
C7	0.3532 (3)	0.8628 (2)	0.65419 (18)	0.0449 (3)
C8	0.44728 (19)	0.77948 (18)	0.54209 (15)	0.0349 (3)
C9	0.33770 (19)	0.63693 (18)	0.38810 (15)	0.0342 (3)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S1	0.0703 (3)	0.0558 (3)	0.0418 (2)	0.0245 (2)	0.01587 (18)	0.00583 (17)
N2	0.0308 (6)	0.0565 (8)	0.0718 (9)	0.0165 (5)	0.0131 (6)	0.0227 (7)
N1	0.0395 (6)	0.0590 (8)	0.0648 (8)	0.0245 (6)	0.0224 (6)	0.0205 (7)
N3	0.0738 (10)	0.0452 (7)	0.0484 (8)	0.0114 (7)	−0.0071 (7)	0.0048 (6)
C1	0.0461 (8)	0.0480 (8)	0.0460 (8)	0.0091 (6)	−0.0026 (6)	0.0096 (6)
C2	0.0311 (6)	0.0470 (7)	0.0487 (8)	0.0118 (5)	0.0057 (5)	0.0139 (6)
C3	0.0390 (6)	0.0418 (7)	0.0426 (7)	0.0178 (5)	0.0136 (5)	0.0139 (5)
C4	0.0314 (6)	0.0393 (7)	0.0492 (7)	0.0090 (5)	0.0024 (5)	0.0151 (6)
C5	0.0450 (8)	0.0463 (8)	0.0611 (10)	0.0050 (7)	−0.0090 (7)	0.0116 (7)
C6	0.0773 (12)	0.0485 (8)	0.0421 (8)	0.0242 (8)	0.0131 (8)	0.0076 (6)
C7	0.0481 (8)	0.0444 (7)	0.0426 (7)	0.0177 (6)	0.0157 (6)	0.0115 (6)
C8	0.0315 (6)	0.0347 (6)	0.0373 (6)	0.0115 (5)	0.0077 (5)	0.0119 (5)
C9	0.0291 (5)	0.0368 (6)	0.0367 (6)	0.0126 (5)	0.0083 (4)	0.0121 (5)

Geometric parameters (Å, º)

S1—C1	1.7058 (19)	C2—H2	0.89 (2)
S1—C3	1.7267 (17)	C3—C9	1.3929 (18)
N2—N1	1.302 (2)	C4—C8	1.4114 (18)
N2—C4	1.375 (2)	C4—C5	1.421 (2)
N1—C3	1.3534 (19)	C5—H5	0.92 (2)
N3—C5	1.293 (3)	C6—C7	1.359 (2)
N3—C6	1.361 (3)	C6—H6	0.97 (2)
C1—C2	1.354 (2)	C7—C8	1.4089 (19)
C1—H1	0.95 (2)	C7—H7	0.97 (3)
C2—C9	1.4205 (18)	C8—C9	1.4136 (18)
C1—S1—C3	90.68 (7)	N3—C5—C4	123.69 (16)
N1—N2—C4	119.47 (12)	N3—C5—H5	115.1 (15)
N2—N1—C3	118.30 (13)	C4—C5—H5	121.2 (15)
C5—N3—C6	117.91 (15)	C7—C6—N3	124.48 (17)
C2—C1—S1	114.11 (12)	C7—C6—H6	117.7 (15)
C2—C1—H1	127.8 (12)	N3—C6—H6	117.8 (15)
S1—C1—H1	118.1 (12)	C6—C7—C8	118.13 (16)
C1—C2—C9	111.69 (14)	C6—C7—H7	112.6 (15)
C1—C2—H2	122.8 (14)	C8—C7—H7	129.3 (15)
C9—C2—H2	125.4 (14)	C7—C8—C4	118.27 (13)
N1—C3—C9	126.65 (14)	C7—C8—C9	126.32 (12)
N1—C3—S1	121.77 (11)	C4—C8—C9	115.40 (12)
C9—C3—S1	111.58 (11)	C3—C9—C8	115.56 (12)
N2—C4—C8	124.60 (13)	C3—C9—C2	111.93 (13)
N2—C4—C5	117.89 (14)	C8—C9—C2	132.50 (12)
C8—C4—C5	117.51 (15)
C4—N2—N1—C3	−0.5 (2)	C6—C7—C8—C9	−179.09 (14)
C3—S1—C1—C2	0.64 (13)	N2—C4—C8—C7	−179.74 (13)
S1—C1—C2—C9	−0.48 (18)	C5—C4—C8—C7	−0.2 (2)
N2—N1—C3—C9	−0.8 (2)	N2—C4—C8—C9	−0.6 (2)
N2—N1—C3—S1	179.35 (11)	C5—C4—C8—C9	178.96 (13)
C1—S1—C3—N1	179.21 (14)	N1—C3—C9—C8	1.4 (2)
C1—S1—C3—C9	−0.63 (11)	S1—C3—C9—C8	−178.80 (9)
N1—N2—C4—C8	1.2 (2)	N1—C3—C9—C2	−179.35 (14)
N1—N2—C4—C5	−178.37 (15)	S1—C3—C9—C2	0.49 (15)
C6—N3—C5—C4	−0.4 (3)	C7—C8—C9—C3	178.46 (13)
N2—C4—C5—N3	−179.99 (16)	C4—C8—C9—C3	−0.58 (18)
C8—C4—C5—N3	0.4 (3)	C7—C8—C9—C2	−0.6 (2)
C5—N3—C6—C7	0.1 (3)	C4—C8—C9—C2	−179.69 (14)
N3—C6—C7—C8	0.1 (3)	C1—C2—C9—C3	−0.02 (18)
C6—C7—C8—C4	−0.1 (2)	C1—C2—C9—C8	179.12 (14)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C1—H1···N3^i	0.943 (19)	2.441 (18)	3.352 (3)	159.1 (18)
C2—H2···N1^ii	0.89 (2)	2.52 (2)	3.360 (2)	158 (2)

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