Crystal structure of pyrazoxyfen

Eunjin Kwon; Jineun Kim; Gihaeng Kang; Tae Ho Kim

doi:10.1107/S2056989015023233

. 2015 Dec 9;71(Pt 12):o1033–o1034. doi: 10.1107/S2056989015023233

Crystal structure of pyrazoxyfen

Eunjin Kwon ^a, Jineun Kim ^a,^*, Gihaeng Kang ^a, Tae Ho Kim ^a,^*

PMCID: PMC4719964 PMID: 26870483

Abstract

The title compound, C₂₀H₁₆Cl₂N₂O₃ (systematic name: 2-{[4-(2,4-dichlorobenzoyl)-1,3-dimethylpyrazol-5-yl}oxy}-1-phenylethan-1-one), is the benzoylpyrazole herbicide pyrazoxyfen. The asymmetric unit comprises two independent molecules, A and B, in which the pyrazole ring makes dihedral angles of 80.29 (10) and 61.70 (10)° and 87.60 (10) and 63.92 (8)°, respectively, with the dichlorophenyl and phenyl rings. In the crystal, C—H⋯O and C—H⋯N hydrogen bonds, and C—H⋯π and π–π [3.646 (2) Å] interactions link adjacent molecules, forming a two-dimensional network parellel to (011). In addition, the networks are linked by weak intermolecular C—Cl⋯π [3.356 (2), 3.950 (2), 3.250 (2) and 3.575 (2) Å] interactions, resulting in a three-dimensional architecture.

Keywords: crystal structure, pyrazoxyfen, acetophenone, herbicide

Related literature

For information on the herbicidal properties of the title compound, see: Hirai et al. (2002 ▸). For a related crystal structure, see: Indumathi et al. (2012 ▸). graphic file with name e-71-o1033-scheme1.jpg

Experimental

Crystal data

C₂₀H₁₆Cl₂N₂O₃
M _r = 403.25
Triclinic,
a = 7.827 (3) Å
b = 15.534 (5) Å
c = 15.886 (6) Å
α = 88.82 (2)°
β = 89.093 (18)°
γ = 77.266 (18)°
V = 1883.4 (11) Å³
Z = 4
Mo Kα radiation
μ = 0.37 mm⁻¹
T = 173 K
0.20 × 0.16 × 0.11 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2014 ▸) T _min = 0.684, T _max = 0.746
22903 measured reflections
6579 independent reflections
3991 reflections with I > 2σ(I)
R _int = 0.063

Refinement

R[F ² > 2σ(F ²)] = 0.049
wR(F ²) = 0.109
S = 0.99
6579 reflections
491 parameters
H-atom parameters constrained
Δρ_max = 0.25 e Å⁻³
Δρ_min = −0.35 e Å⁻³

Data collection: APEX2 (Bruker, 2014 ▸); cell refinement: SAINT (Bruker, 2014 ▸); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▸); program(s) used to refine structure: SHELXL2013 (Sheldrick, 2015 ▸); molecular graphics: DIAMOND (Brandenburg, 2010 ▸); software used to prepare material for publication: SHELXTL (Sheldrick, 2008 ▸).

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S2056989015023233/hg5466sup1.cif

e-71-o1033-sup1.cif^{(763.8KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989015023233/hg5466Isup2.hkl

e-71-o1033-Isup2.hkl^{(360.5KB, hkl)}

Click here for additional data file.^{(6.9KB, cml)}

Supporting information file. DOI: 10.1107/S2056989015023233/hg5466Isup3.cml

Click here for additional data file.^{(1.6MB, tif)}

. DOI: 10.1107/S2056989015023233/hg5466fig1.tif

The asymmetric unit of the title compound with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms are shown as small spheres of arbitrary radius.

Click here for additional data file.^{(1.4MB, tif)}

a . DOI: 10.1107/S2056989015023233/hg5466fig2.tif

Crystal packing viewed along the a axis. The intermolecular interactions are shown as dashed lines.

CCDC reference: 1440271

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

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

Cg3 and Cg6 are the centroids of the C15–C20 and C35–C40 rings, respectively.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C12—H12A⋯O1ⁱ	0.98	2.42	3.353 (4)	159
C32—H32A⋯O4ⁱ	0.98	2.45	3.420 (4)	168
C16—H16⋯N2ⁱⁱ	0.95	2.51	3.414 (4)	159
C36—H36⋯N4ⁱⁱ	0.95	2.54	3.334 (4)	141
C37—H37⋯O6ⁱⁱ	0.95	2.55	3.490 (4)	172
C25—H25⋯O4ⁱⁱⁱ	0.95	2.56	3.302 (4)	135
C39—H39⋯O3^iv	0.95	2.54	3.346 (4)	143
C33—H33A⋯Cg6^v	0.99	2.97	3.683 (3)	130
C38—H38⋯Cg3^vi	0.95	2.68	3.499 (3)	145

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) ; (v) ; (vi) .

Acknowledgments

This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (No. 2015R1D1A4A01020317).

supplementary crystallographic information

S1. Comment

Pyrazoxyfen [systematic name: 2-[4-(2,4-dichlorobenzoyl)-1,3-dimethylpyrazol-5-yloxy]acetophenone] is a the benzoyl pyrazole herbicides. Various pyrazole derivatives with potent herbicidal activity have been synthesized and some are in use as herbicides such as pyrazolate, pyrazoxyfen, benzofenap, pyraflufen-ethyl, fluazolate and pyrazosulfuron-ethyl (Hirai et al., 2002). The asymmetric unit comprises two independent molecules, A and B, in which the dihedral angle between the dichlorophenyl and pyrazole and phenyl ring planes are 80.29 (10), 61.70 (10), 87.60 (10), and 63.92 (8)°, respectively. All bond lengths and bond angles are normal and comparable to those observed in similar crystal structures (Indumathi et al., 2012).

In the crystal structure (Fig. 2), C–H···O and C–H···N hydrogen bonds, C–H···π (Table 1), and Cg3···Cg3^vi, 3.646 (2) Å (Cg3 is the centroid of the C15—C20 ring) interactions link adjacent molecules, forming a two-dimensional network parelle to (011) plane. In addition, the networks are linked by weak intermolecular C1–Cl1···Cg4ⁱⁱⁱ, 3.356 (2), C3–Cl2···Cg6, 3.950 (2), C21–Cl3···Cg1^vii, 3.250 (2) and C21–Cl3···Cg2ⁱ, 3.575 (2) Å (Cg1, Cg2, Cg4 and Cg6 are the centroids of the N1—N2—C8—C9—C10, C1—C6, N3—N4—C28—C29—C30 and C35–C40 rings) interactions, resulting in a three-dimensional architecture [for Symmetry codes (i) x + 1, y, z; (ii) x − 1, y, z; (iii) −x + 1, −y + 2, −z; (iv) −x + 1, −y + 1, −z + 1; (v) −x + 1, −y + 1, −z; (vi) −x, −y + 1, −z + 1, (vii) −x + 1, −y + 2, −z + 1].

S2. Experimental

The title compound was purchased from the Dr. Ehrenstorfer GmbH Company. Slow evaporation of a solution in CH₃CN gave single crystals suitable for X-ray analysis.