Crystal structure of fipronil.

The title compound, C12H4Cl2F6N4OS {systematic name: 5-amino-1-[2,6-di-chloro-4-(tri-fluoro-meth-yl)phen-yl]-4-[(tri-fluoro-methane)sulfinyl]-1H-pyrazole-3-carbo-nitrile}, is a member of the phenyl-pyrazole group of acaricides, and one of the phenyl-pyrazole group of insecticides. The dihedral angle between the planes of the pyrazole and benzene rings is 89.03 (9)°. The fluorine atoms of the tri-fluoro-methyl substituent on the benzene ring are disordered over two sets of sites, with occupancy ratios 0.620 (15):0.380 (15). In the crystal, C-N⋯π inter-actions [N⋯ring centroid = 3.607 (4) Å] together with N-H⋯N and C-H⋯F hydrogen bonds form a looped chain structure along [10[Formula: see text]]. Finally, N-H⋯O hydrogen bonds and C-Cl⋯π inter-actions [Cl⋯ring centroid = 3.5159 (16) Å] generate a three-dimensional structure. Additionally, there are a short inter-molecular F⋯ F contacts present.

Chemical context

Fipronil is an insecticide that belongs to the phenyl­pyrazole group. It is an insecticide with extended use in the control of many agricultural vermin. Fipronil contains a tri­fluoro­methyl­sulfinyl substituent that is not present in any other agrochemicals and this is thought to contribute to its remarkable potency in the field (Hainzl & Casida, 1996 ▸). In addition, it is a highly effective and broad-spectrum insecticide against piercing–sucking, contact and chewing pests and is widely used to control many species of soil and foliar insects on various crops including rice, vegetables and fruits (Kaur et al., 2015 ▸). The toxicity of fipronil is attributed to its ability to act at the GABA receptor as a non-competitive inhibitor of the GABA-gated chloride channels of neurons in the central nervous system. Impediments to the influx of the chloride ions affect the transmission of nervous impulses, causing insect death by neuronal hyperexcitation and paralysis (Medeiros et al., 2015 ▸). Recently, eggs contaminated with fipronil have been found in Europe, Hong Kong and the Republic of Korea. We report here the crystal structure of fipronil, 5-amino-1-[2,6-di­chloro-4-(tri­fluoro­meth­yl)phen­yl]-4-(tri­fluoro­methane­sul­fin­yl)-1H-pyrazole-3-carbo­nitrile.

Structural commentary

The mol­ecular structure of the title compound is shown in Fig. 1 ▸. The dihedral angle between the planes of the pyrazole and benzene rings is 89.03 (9)°. All bond lengths and bond angles are normal and comparable to those observed in similar crystal structures (Kang et al., 2015 ▸; Jiang & Xu, 2009 ▸).

Figure 1

The structure of the title compound, with displacement ellipsoids drawn at the 50% probability level. H atoms are shown as small spheres of arbitrary radius.

Supra­molecular features

In the crystal, mol­ecules are linked by C12—N4⋯Cg1iii inter­actions [N⋯Cg1 = 3.607 (4) Å; Cg1 is the centroid of the C5–C10 ring; symmetry code: (iii) − + x,  − y, − + z], together with N3—H3A⋯N4i and C9—H9⋯F2i hydrogen bonds, forming looped chains along [10] (Fig. 2 ▸). Inversion-related C10—Cl2⋯Cg1iv inter­actions [Cl⋯Cg1 = 3.5159 (16)Å; symmetry code: (iv) 2 − x, −y, 2 − z] (red dashed lines), link adjacent chains, resulting in a two-dimensional network parallel to the (10) plane (Fig. 3 ▸). Finally, classical N3—H3B⋯O1ii hydrogen bonds (black dashed lines) combine with these contacts to generate a three-dimensional network structure (Fig. 4 ▸ and Table 1 ▸). Short F2⋯F4′v [2.762 (14) Å] and F3⋯F6′vi [2.855 (12) Å] inter­actions are also present [symmetry codes: (v) − + x,  − y, − + z; (vi) − + x,  + y, −1 + z].

Figure 2

A view along the b axis of the crystal packing of the title compound. Looped chains are formed through inter­molecular C—N⋯π inter­actions together with N—H⋯N and C—H⋯F hydrogen bonds (yellow dashed lines). H atoms not involved in inter­molecular inter­actions have been omitted for clarity.

Figure 3

The two-dimensional network formed through inter­molecular C—Cl⋯π inter­actions (red dashed lines). H atoms not involved in inter­molecular inter­actions have been omitted for clarity.

Figure 4

The overall packing of the title compound, showing the three-dimensional network formed through N—H⋯O hydrogen bonds (black dashed lines). H atoms not involved in inter­molecular inter­actions have been omitted for clarity.

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N3—H3A⋯N4i	0.88	2.39	3.183 (3)	151
N3—H3B⋯O1ii	0.88	2.28	2.896 (3)	127
C9—H9⋯F2i	0.95	2.42	3.222 (3)	143

Symmetry codes: (i) ; (ii) .

Database survey

The title compound has been used as a starting material for the synthesis of other materials (Tang et al., 2005 ▸; Liu et al., 2013 ▸). Moreover, the structures of CuII, CdII, ZnII and MnII complexes using fipronil as a ligand are known (Tang et al., 2009 ▸, 2010 ▸). The crystal structures of other phenyl­pyrazole compounds such as ethyl 7-methyl-2-phenyl­pyrazolo­[1,5-a]pyrimidine-5-carboxyl­ate (Bassoude et al., 2013 ▸) and 4-{[(E)-(3,5-dimethyl-1-phenyl-1H-pyrazol-4-yl)methyl­idene]amino}-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one (Fun et al., 2010 ▸) have also been reported.

Synthesis and crystallization

The title compound was purchased from Dr. Ehrenstorfer GmbH. Colourless single crystals suitable for X-ray diffraction were obtained from a CH3CN solution by slow evaporation at room temperature.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2 ▸. All H atoms were positioned geometrically and refined using a riding model with d(N—H) = 0.88 Å, U iso = 1.2U eq(C) for the N—H group, d(C—H) = 0.95 Å, U iso = 1.2U eq(C) for aromatic C—H. Atoms F4–F6 of the CF3 substituent are disordered over two sets of sites. Their occupancies refined to 0.620 (15) and 0.380 (15).

Table 2

Experimental details

Crystal data
Chemical formula	C12H4Cl2F6N4OS
M r	437.15
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	173
a, b, c (Å)	22.5649 (16), 12.6823 (9), 14.9051 (11)
β (°)	129.699 (3)
V (Å3)	3281.9 (4)
Z	8
Radiation type	Mo Kα
μ (mm−1)	0.60
Crystal size (mm)	0.15 × 0.13 × 0.04
Data collection
Diffractometer	Bruker APEXII CCD
Absorption correction	Multi-scan (SADABS; Bruker, 2014 ▸)
T min, T max	0.587, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections	14125, 3731, 2506
R int	0.066
(sin θ/λ)max (Å−1)	0.648
Refinement
R[F 2 > 2σ(F 2)], wR(F 2), S	0.048, 0.120, 1.03
No. of reflections	3731
No. of parameters	263
No. of restraints	36
H-atom treatment	H-atom parameters constrained
Δρmax, Δρmin (e Å−3)	0.38, −0.32

Computer programs: APEX2 and SAINT (Bruker, 2014 ▸), SHELXS97 and SHELXTL (Sheldrick, 2008 ▸), SHELXL2014 (Sheldrick, 2015 ▸), DIAMOND (Brandenburg, 2010 ▸) and publCIF (Westrip, 2010 ▸).

Crystal structure: contains datablock(s) I, New_Global_Publ_Block. DOI: 10.1107/S205698901701310X/sj5534sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S205698901701310X/sj5534Isup2.hkl

CCDC reference: 1574261

Additional supporting information: crystallographic information; 3D view; checkCIF report

C12H4Cl2F6N4OS	F(000) = 1728
Mr = 437.15	Dx = 1.769 Mg m−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 22.5649 (16) Å	Cell parameters from 2101 reflections
b = 12.6823 (9) Å	θ = 2.4–21.6°
c = 14.9051 (11) Å	µ = 0.60 mm−1
β = 129.699 (3)°	T = 173 K
V = 3281.9 (4) Å3	Plate, colourless
Z = 8	0.15 × 0.13 × 0.04 mm

Bruker APEXII CCD diffractometer	2506 reflections with I > 2σ(I)
φ and ω scans	Rint = 0.066
Absorption correction: multi-scan (SADABS; Bruker, 2014)	θmax = 27.4°, θmin = 2.0°
Tmin = 0.587, Tmax = 0.746	h = −28→29
14125 measured reflections	k = −16→16
3731 independent reflections	l = −19→19

Refinement on F2	36 restraints
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.048	H-atom parameters constrained
wR(F2) = 0.120	w = 1/[σ2(Fo2) + (0.0463P)2 + 0.8977P] where P = (Fo2 + 2Fc2)/3
S = 1.03	(Δ/σ)max = 0.001
3731 reflections	Δρmax = 0.38 e Å−3
263 parameters	Δρmin = −0.32 e Å−3

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

	x	y	z	Uiso*/Ueq	Occ. (<1)
Cl1	0.94088 (4)	0.32995 (6)	1.06637 (7)	0.0429 (2)
Cl2	1.04310 (4)	0.06765 (6)	0.90739 (7)	0.0417 (2)
S1	0.83382 (4)	0.44166 (6)	0.63886 (6)	0.0337 (2)
F1	0.89072 (10)	0.55280 (14)	0.83001 (16)	0.0516 (5)
F2	0.77293 (11)	0.50457 (17)	0.7312 (2)	0.0695 (7)
F3	0.80245 (12)	0.62984 (14)	0.66925 (18)	0.0673 (6)
F4	1.2426 (3)	0.1359 (8)	1.3877 (5)	0.084 (2)	0.620 (15)
F5	1.1906 (7)	−0.0112 (5)	1.3561 (5)	0.110 (4)	0.620 (15)
F6	1.1641 (4)	0.1123 (8)	1.4199 (6)	0.075 (2)	0.620 (15)
F4'	1.2399 (5)	0.0680 (16)	1.3697 (9)	0.081 (4)	0.380 (15)
F5'	1.1577 (6)	−0.0083 (10)	1.3614 (9)	0.075 (3)	0.380 (15)
F6'	1.1875 (10)	0.1483 (11)	1.4220 (10)	0.092 (5)	0.380 (15)
O1	0.89951 (12)	0.48383 (17)	0.6504 (2)	0.0470 (6)
N1	0.93791 (12)	0.22985 (17)	0.88474 (19)	0.0279 (5)
N2	0.86486 (12)	0.18765 (17)	0.8196 (2)	0.0321 (6)
N3	1.00700 (13)	0.37326 (19)	0.8898 (2)	0.0376 (6)
H3A	1.0499	0.3510	0.9563	0.045*
H3B	1.0072	0.4310	0.8572	0.045*
N4	0.67806 (14)	0.2159 (2)	0.5679 (3)	0.0525 (8)
C1	0.82489 (17)	0.5375 (2)	0.7227 (3)	0.0398 (8)
C2	0.86620 (15)	0.3372 (2)	0.7357 (2)	0.0291 (6)
C3	0.94140 (15)	0.3194 (2)	0.8382 (2)	0.0278 (6)
C4	0.82316 (15)	0.2528 (2)	0.7293 (2)	0.0304 (6)
C5	0.99688 (14)	0.1918 (2)	0.9991 (2)	0.0268 (6)
C6	1.00414 (16)	0.2340 (2)	1.0918 (3)	0.0302 (6)
C7	1.06225 (16)	0.2006 (2)	1.2042 (2)	0.0325 (7)
H7	1.0673	0.2297	1.2676	0.039*
C8	1.11308 (15)	0.1241 (2)	1.2236 (2)	0.0319 (7)
C9	1.10661 (15)	0.0802 (2)	1.1335 (2)	0.0307 (7)
H9	1.1411	0.0264	1.1480	0.037*
C10	1.04895 (15)	0.1158 (2)	1.0209 (2)	0.0287 (6)
C11	1.1763 (2)	0.0878 (3)	1.3460 (3)	0.0481 (9)
C12	0.74238 (17)	0.2320 (2)	0.6396 (3)	0.0364 (7)

	U11	U22	U33	U12	U13	U23
Cl1	0.0409 (5)	0.0398 (4)	0.0512 (5)	0.0144 (3)	0.0308 (4)	0.0070 (3)
Cl2	0.0381 (4)	0.0498 (5)	0.0383 (5)	0.0030 (3)	0.0249 (4)	−0.0050 (3)
S1	0.0242 (4)	0.0383 (4)	0.0292 (4)	0.0042 (3)	0.0127 (4)	0.0077 (3)
F1	0.0376 (11)	0.0530 (12)	0.0410 (12)	0.0005 (9)	0.0143 (10)	−0.0068 (8)
F2	0.0514 (13)	0.0723 (15)	0.1067 (19)	−0.0067 (11)	0.0606 (14)	−0.0199 (13)
F3	0.0577 (13)	0.0370 (11)	0.0654 (14)	0.0157 (9)	0.0200 (12)	0.0090 (9)
F4	0.026 (2)	0.100 (5)	0.060 (3)	−0.007 (3)	−0.003 (2)	0.023 (3)
F5	0.138 (7)	0.048 (3)	0.041 (3)	0.043 (4)	0.010 (3)	0.010 (2)
F6	0.059 (3)	0.125 (6)	0.037 (3)	0.020 (3)	0.030 (3)	0.022 (3)
F4'	0.039 (4)	0.128 (9)	0.063 (5)	0.019 (5)	0.026 (4)	0.048 (5)
F5'	0.062 (5)	0.087 (6)	0.058 (4)	0.006 (4)	0.031 (4)	0.046 (4)
F6'	0.103 (8)	0.081 (6)	0.030 (4)	0.037 (6)	0.013 (5)	−0.001 (4)
O1	0.0429 (13)	0.0494 (14)	0.0594 (15)	0.0056 (11)	0.0376 (13)	0.0151 (11)
N1	0.0143 (11)	0.0307 (12)	0.0257 (13)	−0.0012 (9)	0.0067 (11)	0.0049 (9)
N2	0.0178 (11)	0.0313 (13)	0.0332 (14)	−0.0032 (10)	0.0098 (11)	0.0022 (10)
N3	0.0169 (12)	0.0442 (15)	0.0356 (15)	−0.0038 (10)	0.0093 (12)	0.0110 (11)
N4	0.0248 (15)	0.0419 (16)	0.0570 (19)	−0.0042 (12)	0.0104 (15)	−0.0070 (13)
C1	0.0229 (15)	0.0400 (18)	0.045 (2)	0.0010 (13)	0.0164 (16)	0.0011 (14)
C2	0.0166 (13)	0.0316 (15)	0.0286 (16)	0.0007 (11)	0.0096 (13)	0.0033 (11)
C3	0.0210 (14)	0.0306 (15)	0.0285 (16)	0.0021 (11)	0.0144 (13)	0.0035 (12)
C4	0.0165 (13)	0.0294 (15)	0.0325 (16)	0.0005 (11)	0.0097 (13)	−0.0011 (12)
C5	0.0189 (13)	0.0267 (14)	0.0264 (15)	−0.0023 (11)	0.0106 (13)	0.0033 (11)
C6	0.0248 (15)	0.0264 (14)	0.0361 (17)	0.0032 (11)	0.0178 (14)	0.0025 (12)
C7	0.0316 (16)	0.0332 (15)	0.0286 (16)	−0.0008 (13)	0.0173 (15)	−0.0011 (12)
C8	0.0226 (15)	0.0326 (16)	0.0288 (16)	−0.0006 (12)	0.0110 (14)	0.0045 (12)
C9	0.0221 (14)	0.0280 (15)	0.0364 (17)	0.0031 (11)	0.0161 (14)	0.0044 (12)
C10	0.0232 (14)	0.0282 (15)	0.0302 (16)	−0.0013 (11)	0.0150 (14)	−0.0004 (11)
C11	0.040 (2)	0.055 (2)	0.0331 (19)	0.0070 (17)	0.0153 (18)	0.0064 (16)
C12	0.0237 (16)	0.0269 (15)	0.0414 (19)	−0.0029 (12)	0.0128 (15)	−0.0019 (13)

Cl1—C6	1.724 (3)	N2—C4	1.327 (3)
Cl2—C10	1.723 (3)	N3—C3	1.340 (3)
S1—O1	1.479 (2)	N3—H3A	0.8800
S1—C2	1.739 (3)	N3—H3B	0.8800
S1—C1	1.844 (3)	N4—C12	1.144 (4)
F1—C1	1.329 (3)	C2—C3	1.398 (4)
F2—C1	1.325 (3)	C2—C4	1.408 (4)
F3—C1	1.321 (4)	C4—C12	1.437 (4)
F4—C11	1.344 (7)	C5—C10	1.388 (4)
F5—C11	1.281 (7)	C5—C6	1.389 (4)
F6—C11	1.331 (8)	C6—C7	1.379 (4)
F4'—C11	1.265 (9)	C7—C8	1.384 (4)
F5'—C11	1.357 (11)	C7—H7	0.9500
F6'—C11	1.253 (13)	C8—C9	1.373 (4)
N1—C3	1.359 (3)	C8—C11	1.500 (4)
N1—N2	1.379 (3)	C9—C10	1.387 (4)
N1—C5	1.418 (3)	C9—H9	0.9500
O1—S1—C2	108.69 (13)	C7—C6—C5	120.5 (3)
O1—S1—C1	102.58 (14)	C7—C6—Cl1	119.7 (2)
C2—S1—C1	96.30 (14)	C5—C6—Cl1	119.9 (2)
C3—N1—N2	113.4 (2)	C6—C7—C8	119.1 (3)
C3—N1—C5	125.6 (2)	C6—C7—H7	120.4
N2—N1—C5	119.7 (2)	C8—C7—H7	120.4
C4—N2—N1	103.1 (2)	C9—C8—C7	121.6 (3)
C3—N3—H3A	120.0	C9—C8—C11	119.3 (3)
C3—N3—H3B	120.0	C7—C8—C11	119.1 (3)
H3A—N3—H3B	120.0	C8—C9—C10	118.9 (3)
F3—C1—F2	108.4 (3)	C8—C9—H9	120.6
F3—C1—F1	107.4 (3)	C10—C9—H9	120.6
F2—C1—F1	107.9 (3)	C9—C10—C5	120.6 (3)
F3—C1—S1	110.0 (2)	C9—C10—Cl2	119.8 (2)
F2—C1—S1	110.0 (2)	C5—C10—Cl2	119.6 (2)
F1—C1—S1	112.9 (2)	F6'—C11—F4'	109.4 (8)
C3—C2—C4	104.7 (2)	F5—C11—F6	107.4 (6)
C3—C2—S1	127.2 (2)	F5—C11—F4	105.6 (5)
C4—C2—S1	128.1 (2)	F6—C11—F4	105.6 (5)
N3—C3—N1	122.4 (2)	F6'—C11—F5'	107.5 (9)
N3—C3—C2	132.0 (3)	F4'—C11—F5'	101.2 (7)
N1—C3—C2	105.5 (2)	F6'—C11—C8	113.4 (6)
N2—C4—C2	113.2 (2)	F4'—C11—C8	115.4 (5)
N2—C4—C12	119.1 (3)	F5—C11—C8	114.6 (4)
C2—C4—C12	127.8 (3)	F6—C11—C8	113.3 (4)
C10—C5—C6	119.3 (3)	F4—C11—C8	109.7 (4)
C10—C5—N1	121.4 (3)	F5'—C11—C8	108.9 (5)
C6—C5—N1	119.2 (2)	N4—C12—C4	179.7 (4)
C3—N1—N2—C4	1.3 (3)	N2—N1—C5—C6	−85.1 (3)
C5—N1—N2—C4	169.4 (2)	C10—C5—C6—C7	−0.2 (4)
O1—S1—C1—F3	67.2 (2)	N1—C5—C6—C7	−178.2 (2)
C2—S1—C1—F3	178.0 (2)	C10—C5—C6—Cl1	179.0 (2)
O1—S1—C1—F2	−173.4 (2)	N1—C5—C6—Cl1	1.0 (4)
C2—S1—C1—F2	−62.6 (2)	C5—C6—C7—C8	−0.3 (4)
O1—S1—C1—F1	−52.8 (2)	Cl1—C6—C7—C8	−179.5 (2)
C2—S1—C1—F1	58.0 (2)	C6—C7—C8—C9	−0.5 (4)
O1—S1—C2—C3	24.2 (3)	C6—C7—C8—C11	179.9 (3)
C1—S1—C2—C3	−81.4 (3)	C7—C8—C9—C10	1.8 (4)
O1—S1—C2—C4	−156.3 (3)	C11—C8—C9—C10	−178.7 (3)
C1—S1—C2—C4	98.1 (3)	C8—C9—C10—C5	−2.3 (4)
N2—N1—C3—N3	178.6 (3)	C8—C9—C10—Cl2	176.2 (2)
C5—N1—C3—N3	11.4 (4)	C6—C5—C10—C9	1.5 (4)
N2—N1—C3—C2	−0.3 (3)	N1—C5—C10—C9	179.5 (2)
C5—N1—C3—C2	−167.6 (3)	C6—C5—C10—Cl2	−177.0 (2)
C4—C2—C3—N3	−179.6 (3)	N1—C5—C10—Cl2	1.0 (4)
S1—C2—C3—N3	0.0 (5)	C9—C8—C11—F6'	164.8 (12)
C4—C2—C3—N1	−0.8 (3)	C7—C8—C11—F6'	−15.6 (12)
S1—C2—C3—N1	178.9 (2)	C9—C8—C11—F4'	37.5 (12)
N1—N2—C4—C2	−1.8 (3)	C7—C8—C11—F4'	−142.9 (11)
N1—N2—C4—C12	178.8 (3)	C9—C8—C11—F5	−38.1 (10)
C3—C2—C4—N2	1.7 (3)	C7—C8—C11—F5	141.4 (9)
S1—C2—C4—N2	−177.9 (2)	C9—C8—C11—F6	−161.9 (6)
C3—C2—C4—C12	−179.0 (3)	C7—C8—C11—F6	17.6 (6)
S1—C2—C4—C12	1.4 (5)	C9—C8—C11—F4	80.4 (6)
C3—N1—C5—C10	−96.6 (3)	C7—C8—C11—F4	−100.0 (6)
N2—N1—C5—C10	96.9 (3)	C9—C8—C11—F5'	−75.4 (7)
C3—N1—C5—C6	81.4 (3)	C7—C8—C11—F5'	104.1 (7)

D—H···A	D—H	H···A	D···A	D—H···A
N3—H3A···N4i	0.88	2.39	3.183 (3)	151
N3—H3B···O1ii	0.88	2.28	2.896 (3)	127
C9—H9···F2i	0.95	2.42	3.222 (3)	143