2-(2-Pyridyl­imino)-2H-1,2,4-thia­diazo­lo­[2,3-a]­pyridine

The title compound, C₁₁H₈N₄S, is found to have a symmetrical resonance structure in which both pyridyl-N atoms interact with the S atom forming hemi-bonds. This also results in the formation of a delocalized di­imine region and disturbance of the aromaticity in the pyridyl rings.

Computing details

Data collection: DENZO (Otwinowski & Minor, 1997) and COLLECT (Hooft, 1998); cell refinement: DENZO and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: CAMERON (Watkin & Pearce, 1995).

(II)

Crystal data

C11H8N4S	F(000) = 944
Mr = 228.27	Dx = 1.516 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 10.970 (2) Å	Cell parameters from 42625 reflections
b = 8.986 (2) Å	θ = 2.0–27.5°
c = 20.881 (4) Å	µ = 0.30 mm^−1
β = 103.66 (3)°	T = 150 K
V = 2000.2 (7) Å^3	Plate, pale yellow
Z = 8	0.1 × 0.1 × 0.03 mm

Data collection

Nonius KappaCCD Area Detector diffractometer	2164 reflections with I > 2σ(I)
Radiation source: Nonius FR591 rotating anode	Rint = 0.037
φ and ω scans to fill Ewald sphere	θmax = 27.5°, θmin = 2.0°
Absorption correction: multi-scans (SORTAV; Blessing, 1995)	h = −14→14
Tmin = 0.957, Tmax = 0.994	k = −11→11
42625 measured reflections	l = −27→27
2294 independent reflections

Refinement

Refinement on F^2	0 restraints
Least-squares matrix: full	All H-atom parameters refined
R[F^2 > 2σ(F^2)] = 0.027	w = 1/[σ^2(Fo^2) + (0.0165P)^2 + 1.9948P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.065	(Δ/σ)max = 0.003
S = 1.16	Δρmax = 0.24 e Å^−3
2294 reflections	Δρmin = −0.29 e Å^−3
177 parameters

Special details

Experimental. A combination of φ and ω scans (10 second exposure time and one degree frame increment) were employed to cover an entire hemisphere of reciprocal space.

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
S1	0.18952 (3)	0.02295 (3)	0.521887 (14)	0.02052 (9)
N1	0.11376 (9)	0.15679 (11)	0.44888 (5)	0.0216 (2)
N2	0.03596 (9)	0.25051 (12)	0.53383 (5)	0.0229 (2)
N3	0.11007 (9)	0.10644 (11)	0.62870 (5)	0.0220 (2)
N4	0.24126 (9)	−0.07373 (11)	0.60437 (5)	0.0201 (2)
C1	0.13075 (12)	0.15735 (15)	0.38676 (6)	0.0265 (3)
C2	0.07311 (13)	0.26186 (16)	0.34222 (6)	0.0303 (3)
C3	−0.00437 (12)	0.36816 (16)	0.36191 (7)	0.0304 (3)
C4	−0.02053 (12)	0.36851 (15)	0.42517 (7)	0.0273 (3)
C5	0.04194 (11)	0.25923 (13)	0.46963 (6)	0.0218 (2)
C6	0.10301 (10)	0.13836 (13)	0.56541 (6)	0.0198 (2)
C7	0.18796 (11)	−0.00927 (13)	0.64980 (6)	0.0204 (2)
C8	0.21988 (12)	−0.06373 (14)	0.71512 (6)	0.0252 (3)
C9	0.30527 (12)	−0.17717 (15)	0.73103 (6)	0.0269 (3)
C10	0.35967 (12)	−0.23948 (15)	0.68243 (7)	0.0267 (3)
C11	0.32579 (11)	−0.18580 (14)	0.61937 (6)	0.0239 (2)
H1	0.1864 (14)	0.0798 (18)	0.3765 (7)	0.028 (4)*
H2	0.0868 (16)	0.2621 (19)	0.2991 (8)	0.040 (4)*
H3	−0.0445 (15)	0.4430 (19)	0.3318 (8)	0.036 (4)*
H4	−0.0687 (14)	0.4394 (18)	0.4401 (7)	0.028 (4)*
H8	0.1819 (14)	−0.0177 (18)	0.7469 (8)	0.031 (4)*
H9	0.3303 (15)	−0.2137 (18)	0.7750 (8)	0.035 (4)*
H10	0.4220 (15)	−0.3168 (18)	0.6921 (8)	0.034 (4)*
H11	0.3630 (14)	−0.2203 (17)	0.5841 (8)	0.029 (4)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S1	0.02135 (15)	0.02052 (15)	0.02073 (15)	−0.00246 (11)	0.00706 (10)	−0.00299 (10)
N1	0.0220 (5)	0.0218 (5)	0.0201 (5)	−0.0046 (4)	0.0031 (4)	−0.0006 (4)
N2	0.0221 (5)	0.0220 (5)	0.0247 (5)	−0.0008 (4)	0.0060 (4)	0.0001 (4)
N3	0.0232 (5)	0.0225 (5)	0.0214 (5)	−0.0006 (4)	0.0073 (4)	−0.0017 (4)
N4	0.0201 (5)	0.0207 (5)	0.0201 (5)	−0.0019 (4)	0.0060 (4)	−0.0005 (4)
C1	0.0269 (6)	0.0306 (7)	0.0217 (6)	−0.0052 (5)	0.0049 (5)	−0.0022 (5)
C2	0.0295 (6)	0.0387 (7)	0.0210 (6)	−0.0088 (6)	0.0027 (5)	0.0024 (5)
C3	0.0271 (6)	0.0311 (7)	0.0286 (6)	−0.0066 (5)	−0.0024 (5)	0.0081 (5)
C4	0.0233 (6)	0.0252 (6)	0.0313 (7)	−0.0020 (5)	0.0022 (5)	0.0024 (5)
C5	0.0185 (5)	0.0215 (6)	0.0244 (6)	−0.0060 (4)	0.0028 (4)	−0.0010 (5)
C6	0.0177 (5)	0.0199 (5)	0.0224 (5)	−0.0036 (4)	0.0059 (4)	−0.0041 (4)
C7	0.0195 (5)	0.0210 (5)	0.0214 (5)	−0.0040 (4)	0.0062 (4)	−0.0024 (4)
C8	0.0290 (6)	0.0262 (6)	0.0216 (6)	−0.0023 (5)	0.0083 (5)	−0.0009 (5)
C9	0.0287 (6)	0.0281 (6)	0.0226 (6)	−0.0034 (5)	0.0036 (5)	0.0031 (5)
C10	0.0225 (6)	0.0253 (6)	0.0313 (6)	0.0011 (5)	0.0046 (5)	0.0028 (5)
C11	0.0220 (6)	0.0233 (6)	0.0278 (6)	−0.0005 (5)	0.0085 (5)	−0.0013 (5)

Geometric parameters (Å, º)

S1—C6	1.7915 (12)	N4—C11	1.3546 (16)
S1—N4	1.8926 (11)	C1—C2	1.3671 (19)
S1—N1	1.9653 (11)	C2—C3	1.403 (2)
N1—C5	1.3480 (16)	C3—C4	1.3737 (19)
N1—C1	1.3534 (16)	C4—C5	1.4126 (18)
N2—C6	1.3276 (16)	C7—C8	1.4132 (17)
N2—C5	1.3598 (16)	C8—C9	1.3711 (18)
N3—C6	1.3366 (15)	C9—C10	1.4092 (19)
N3—C7	1.3518 (16)	C10—C11	1.3687 (18)
N4—C7	1.3561 (15)
C6—S1—N4	83.40 (5)	C3—C4—C5	118.54 (13)
C6—S1—N1	82.05 (5)	N1—C5—N2	116.45 (11)
N4—S1—N1	165.42 (5)	N1—C5—C4	119.55 (11)
C5—N1—C1	121.92 (11)	N2—C5—C4	124.00 (12)
C5—N1—S1	109.93 (8)	N2—C6—N3	123.36 (11)
C1—N1—S1	128.10 (9)	N2—C6—S1	119.02 (9)
C6—N2—C5	112.54 (10)	N3—C6—S1	117.61 (9)
C6—N3—C7	111.83 (10)	N3—C7—N4	116.38 (11)
C7—N4—C11	122.72 (11)	N3—C7—C8	125.05 (11)
C7—N4—S1	110.75 (8)	N4—C7—C8	118.54 (11)
C11—N4—S1	126.41 (8)	C9—C8—C7	119.38 (12)
N1—C1—C2	120.56 (13)	C8—C9—C10	120.15 (12)
C1—C2—C3	118.90 (12)	C11—C10—C9	119.19 (12)
C4—C3—C2	120.52 (13)	N4—C11—C10	120.00 (11)