5-(3-Fluoro­phen­yl)-1,3,4-thia­diazol-2-amine

Abstract

The title compound, C₈H₆FN₃S, was synthesized by the reaction of 3-fluoro­benzoic acid and thio­semicarbazide. The dihedral angle between the planes of the thia­diazole and benzene rings is 37.3 (2)°. In the structure, two crystallographically independent mol­ecules form a centrosymmetric dimer, in which two inter­molecular N—H⋯N hydrogen bonds generate an R ₂ ²(8) motif.

Related literature

For the biological activity of 1,3,4-thiadiazole derivatives, see: Nakagawa et al. (1996 ▶); Wang et al. (1999 ▶). For a similar structure, see: Wan et al. (2006 ▶). For bond-length data, see: Allen et al. (1987 ▶).

Experimental

Crystal data

• C₈H₆FN₃S

• M _r = 195.23

• Monoclinic,

• a = 11.345 (2) Å

• b = 7.3130 (15) Å

• c = 11.269 (2) Å

• β = 111.64 (3)°

• V = 869.0 (3) ų

• Z = 4

• Mo Kα radiation

• μ = 0.34 mm⁻¹

• T = 293 K

• 0.20 × 0.10 × 0.10 mm

Data collection

• Enraf–Nonius CAD-4 diffractometer

• Absorption correction: ψ scan (North et al., 1968 ▶) T _min = 0.935, T _max = 0.967

• 1667 measured reflections

• 1584 independent reflections

• 1177 reflections with I > 2σ(I)

• R _int = 0.021

• 3 standard reflections every 200 reflections intensity decay: 1%

Refinement

• R[F ² > 2σ(F ²)] = 0.047

• wR(F ²) = 0.124

• S = 1.01

• 1584 reflections

• 118 parameters

• 13 restraints

• H-atom parameters constrained

• Δρ_max = 0.37 e Å⁻³

• Δρ_min = −0.25 e Å⁻³

Data collection: CAD-4 Software (Enraf–Nonius, 1989 ▶); cell refinement: CAD-4 Software; data reduction: XCAD4 (Harms & Wocadlo, 1995 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

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

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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N3—H3A⋯N2i	0.86	2.14	2.981 (5)	165

Symmetry code: (i) .

supplementary crystallographic information

Comment

1,3,4-Thiadiazole derivatives represent an interesting class of compounds possessing broad spectrum biological activities (Nakagawa et al., 1996). These compounds are known to exhibit diverse biological effects, such as insecticidal, fungicidal activities (Wang et al., 1999). We are focusing our synthetic and structural studies on thiadiazole derivatives and have published the structure of 5-(4-fluoro-phenyl)-[1,3,4]thiadiazol-2-ylamine (Wan et al., 2006). Here we report the crystal structure, (I).

In the title molecule (I), (Fig. 1), the dihedral angle between the thiadiazole and benzene ring is 37.3 (2)°, which is bigger than the angle in the structure of 5-(4-fluoro-phenyl)-[1,3,4]thiadiazol-2-ylamine (Wan et al., 2006), which is 30.1 (2)°. In the structure, two crystallographically independent molecules form a dimer structure, in which two intermolecular N—H···N hydrogen bonds generate a motif R₂²(8) (Fig. 2).

Experimental

3-Fluoro-benzoic acid (2 mmol) and thiosemicarbazide (5 mmol) were mixed in a 25 ml flask, and kept in the oil bath at 363 K for 6 h. After cooling, the crude product (I) precipitated and was filted. Pure compound (I) was obtained by crystallization from ethanol (20 ml). Crystals of (I) suitable for X-ray diffraction were obtained by slow evaporation of an acetone solution.

Refinement

All H atoms were placed geometrically with C—H = 0.93 Å and N—H = 0.86 Å, and included in the refinement in riding motion approximation with U_iso(H) = 1.2U_eq of the carrier atom.

Figures

Fig. 1.

A view of the molecular structure of (I). Displacement ellipsoids are drawn at the 50% probability level.

Fig. 2.

A view of a dimer structure, in which two intermolecular N—H···N hydrogen bonds generate a motif R22(8).

Crystal data

C8H6FN3S	F(000) = 400
Mr = 195.23	Dx = 1.492 Mg m−3
Monoclinic, P21/c	Melting point: 515 K
Hall symbol: -P 2ybc	Mo Kα radiation, λ = 0.71073 Å
a = 11.345 (2) Å	Cell parameters from 25 reflections
b = 7.3130 (15) Å	θ = 10–13°
c = 11.269 (2) Å	µ = 0.34 mm−1
β = 111.64 (3)°	T = 293 K
V = 869.0 (3) Å3	Block, colourless
Z = 4	0.20 × 0.10 × 0.10 mm

Data collection

Enraf–Nonius CAD-4 diffractometer	1177 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.021
graphite	θmax = 25.3°, θmin = 1.9°
ω/2θ scans	h = −13→0
Absorption correction: ψ scan (North et al., 1968)	k = 0→8
Tmin = 0.935, Tmax = 0.967	l = −12→13
1667 measured reflections	3 standard reflections every 200 reflections
1584 independent reflections	intensity decay: 1%

Refinement

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.047	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.124	H-atom parameters constrained
S = 1.01	w = 1/[σ2(Fo2) + (0.06P)2] where P = (Fo2 + 2Fc2)/3
1584 reflections	(Δ/σ)max < 0.001
118 parameters	Δρmax = 0.37 e Å−3
13 restraints	Δρmin = −0.25 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
S	0.82144 (7)	0.08639 (11)	0.55908 (6)	0.0548 (3)
F	0.5162 (3)	−0.2428 (3)	0.0198 (2)	0.1125 (9)
N1	0.8658 (2)	0.1443 (3)	0.3566 (2)	0.0523 (6)
C1	0.7322 (3)	−0.2918 (5)	0.3984 (3)	0.0713 (9)
H1B	0.7804	−0.3036	0.4850	0.086*
N2	0.9262 (2)	0.2841 (3)	0.4381 (2)	0.0551 (6)
C2	0.6592 (4)	−0.4354 (5)	0.3322 (4)	0.0817 (11)
H2B	0.6585	−0.5443	0.3746	0.098*
N3	0.9606 (3)	0.3931 (4)	0.6429 (2)	0.0733 (9)
H3A	1.0043	0.4846	0.6340	0.088*
H3B	0.9481	0.3787	0.7131	0.088*
C3	0.5871 (4)	−0.4202 (5)	0.2040 (4)	0.0822 (12)
H3C	0.5378	−0.5175	0.1592	0.099*
C4	0.5898 (3)	−0.2597 (6)	0.1447 (3)	0.0741 (10)
C5	0.6637 (3)	−0.1132 (4)	0.2071 (3)	0.0639 (9)
H5A	0.6658	−0.0066	0.1628	0.077*
C6	0.7338 (3)	−0.1272 (4)	0.3350 (3)	0.0516 (7)
C7	0.8082 (3)	0.0307 (4)	0.4039 (2)	0.0475 (7)
C8	0.9121 (3)	0.2733 (4)	0.5476 (2)	0.0499 (7)

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
S	0.0686 (5)	0.0626 (5)	0.0402 (4)	−0.0130 (4)	0.0282 (3)	0.0002 (3)
F	0.1200 (19)	0.122 (2)	0.0888 (16)	−0.0253 (16)	0.0307 (14)	−0.0193 (15)
N1	0.0646 (15)	0.0583 (14)	0.0421 (12)	−0.0113 (12)	0.0293 (11)	−0.0079 (11)
C1	0.070 (2)	0.068 (2)	0.073 (2)	−0.0121 (18)	0.0235 (17)	0.0023 (18)
N2	0.0753 (16)	0.0580 (15)	0.0433 (12)	−0.0172 (13)	0.0353 (12)	−0.0097 (11)
C2	0.074 (2)	0.060 (2)	0.112 (3)	−0.0081 (19)	0.035 (2)	0.001 (2)
N3	0.110 (2)	0.0800 (19)	0.0452 (14)	−0.0379 (17)	0.0462 (15)	−0.0191 (13)
C3	0.074 (2)	0.079 (3)	0.104 (3)	−0.020 (2)	0.045 (2)	−0.040 (2)
C4	0.075 (2)	0.091 (3)	0.062 (2)	−0.024 (2)	0.0319 (18)	−0.0344 (19)
C5	0.075 (2)	0.068 (2)	0.0514 (17)	−0.0144 (17)	0.0271 (16)	−0.0140 (16)
C6	0.0557 (17)	0.0533 (17)	0.0519 (16)	0.0000 (13)	0.0270 (14)	−0.0051 (13)
C7	0.0541 (16)	0.0513 (16)	0.0421 (14)	0.0000 (13)	0.0236 (13)	−0.0013 (12)
C8	0.0634 (18)	0.0556 (17)	0.0374 (13)	−0.0068 (14)	0.0265 (13)	−0.0025 (13)

Geometric parameters (Å, °)

S—C8	1.744 (3)	C2—H2B	0.9300
S—C7	1.747 (3)	N3—C8	1.338 (3)
F—C4	1.351 (4)	N3—H3A	0.8600
N1—C7	1.288 (3)	N3—H3B	0.8600
N1—N2	1.377 (3)	C3—C4	1.357 (5)
C1—C2	1.375 (5)	C3—H3C	0.9300
C1—C6	1.403 (4)	C4—C5	1.382 (4)
C1—H1B	0.9300	C5—C6	1.369 (4)
N2—C8	1.303 (3)	C5—H5A	0.9300
C2—C3	1.378 (5)	C6—C7	1.472 (4)
C8—S—C7	86.76 (13)	F—C4—C3	118.3 (3)
C7—N1—N2	114.0 (2)	F—C4—C5	119.0 (4)
C2—C1—C6	119.8 (3)	C3—C4—C5	122.7 (3)
C2—C1—H1B	120.1	C6—C5—C4	119.0 (3)
C6—C1—H1B	120.1	C6—C5—H5A	120.5
C8—N2—N1	112.5 (2)	C4—C5—H5A	120.5
C1—C2—C3	120.9 (4)	C5—C6—C1	119.3 (3)
C1—C2—H2B	119.6	C5—C6—C7	119.6 (3)
C3—C2—H2B	119.6	C1—C6—C7	121.1 (3)
C8—N3—H3A	120.0	N1—C7—C6	124.6 (2)
C8—N3—H3B	120.0	N1—C7—S	113.2 (2)
H3A—N3—H3B	120.0	C6—C7—S	122.1 (2)
C4—C3—C2	118.3 (3)	N2—C8—N3	124.3 (3)
C4—C3—H3C	120.9	N2—C8—S	113.5 (2)
C2—C3—H3C	120.9	N3—C8—S	122.19 (19)
C7—N1—N2—C8	−0.2 (4)	N2—N1—C7—S	0.5 (3)
C6—C1—C2—C3	−0.1 (5)	C5—C6—C7—N1	−36.0 (4)
C1—C2—C3—C4	−0.1 (6)	C1—C6—C7—N1	144.6 (3)
C2—C3—C4—F	−178.1 (3)	C5—C6—C7—S	141.4 (3)
C2—C3—C4—C5	1.3 (6)	C1—C6—C7—S	−37.9 (4)
F—C4—C5—C6	177.0 (3)	C8—S—C7—N1	−0.4 (2)
C3—C4—C5—C6	−2.4 (5)	C8—S—C7—C6	−178.2 (2)
C4—C5—C6—C1	2.2 (5)	N1—N2—C8—N3	−179.5 (3)
C4—C5—C6—C7	−177.2 (3)	N1—N2—C8—S	−0.1 (3)
C2—C1—C6—C5	−1.0 (5)	C7—S—C8—N2	0.3 (2)
C2—C1—C6—C7	178.4 (3)	C7—S—C8—N3	179.7 (3)
N2—N1—C7—C6	178.1 (2)

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
N3—H3A···N2i	0.86	2.14	2.981 (5)	165

Symmetry codes: (i) −x+2, −y+1, −z+1.