research communications
of fipronil
aDepartment of Chemistry (BK21 plus) and Research Institute of Natural Sciences, Gyeongsang National University, Jinju 52828, Republic of Korea
*Correspondence e-mail: thkim@gnu.ac.kr, jekim@gnu.ac.kr
The title compound, C12H4Cl2F6N4OS {systematic name: 5-amino-1-[2,6-dichloro-4-(trifluoromethyl)phenyl]-4-[(trifluoromethane)sulfinyl]-1H-pyrazole-3-carbonitrile}, is a member of the phenylpyrazole group of acaricides, and one of the phenylpyrazole group of insecticides. The dihedral angle between the planes of the pyrazole and benzene rings is 89.03 (9)°. The fluorine atoms of the trifluoromethyl 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 interactions [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]. Finally, N—H⋯O hydrogen bonds and C—Cl⋯π interactions [Cl⋯ring centroid = 3.5159 (16) Å] generate a three-dimensional structure. Additionally, there are a short intermolecular F⋯ F contacts present.
Keywords: crystal structure; fipronil; acaricides; insecticides.
CCDC reference: 1574261
1. 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 of fipronil, 5-amino-1-[2,6-dichloro-4-(trifluoromethyl)phenyl]-4-(trifluoromethanesulfinyl)-1H-pyrazole-3-carbonitrile.
2. 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).
3. 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].
4. 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.
5. 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.
6. Refinement
Crystal data, data collection and structure . All H atoms were positioned geometrically and refined using a riding model with d(N—H) = 0.88 Å, Uiso = 1.2Ueq(C) for the N—H group, d(C—H) = 0.95 Å, Uiso = 1.2Ueq(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).
details are summarized in Table 2Supporting information
CCDC reference: 1574261
https://doi.org/10.1107/S205698901701310X/sj5534sup1.cif
contains datablocks I, New_Global_Publ_Block. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S205698901701310X/sj5534Isup2.hkl
Data collection: APEX2 (Bruker, 2014); cell
SAINT (Bruker, 2014); data reduction: SAINT (Bruker, 2014); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: DIAMOND (Brandenburg, 2010); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and publCIF (Westrip, 2010).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 |
Symmetry codes: (i) x+1/2, −y+1/2, z+1/2; (ii) −x+2, y, −z+3/2. |
Funding information
This research was supported by the Basic Science Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (No. 2015R1D1A4A01020317 and 2017R1D1A3A03000534).
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