Crystal structure of fluroxypyr

The title compound {systematic name: 2-[(4-amino-3,5-di­chloro-6-fluoro­pyridin-2-yl)­oxy]acetic acid}, C₇H₅Cl₂FN₂O₃, is a pyridine herbicide. In the crystal, N—H...O, O—H...O and N—H...F hydrogen bonds and weak π–π inter­actions connect chains of mol­ecules into a three-dimensional network.

Key indicators

• Single-crystal X-ray study
• T = 173 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.028
• wR factor = 0.076
• Data-to-parameter ratio = 15.3

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT001_ALERT_1_C No _shelx_res_file DataName found in SHELXL CIF      Please Do !
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.600          6 Report

Alert level G
PLAT007_ALERT_5_G Number of Unrefined Donor-H Atoms ..............          3 Report
PLAT431_ALERT_2_G Short Inter HL..A  Contact Cl1    ..  O2      ..       3.17 Ang.
PLAT912_ALERT_4_G Missing # of FCF Reflections Above STh/L=  0.600          4 Note
PLAT978_ALERT_2_G Number C-C Bonds with Positive Residual Density           5 Note

   0 ALERT level A = Most likely a serious problem - resolve or explain
   0 ALERT level B = A potentially serious problem, consider carefully
   2 ALERT level C = Check. Ensure it is not caused by an omission or oversight
   4 ALERT level G = General information/check it is not something unexpected

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   2 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   1 ALERT type 5 Informative message, check

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Computing details

Data collection: APEX2 (Bruker, 2014); cell refinement: 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).

2-[(4-Amino-3,5-dichloro-6-fluoropyridin-2-yl)oxy]acetic acid

Crystal data

C7H5Cl2FN2O3	Z = 2
Mr = 255.03	F(000) = 256
Triclinic, P1	Dx = 1.860 Mg m^−3
a = 7.1116 (9) Å	Mo Kα radiation, λ = 0.71073 Å
b = 7.6131 (9) Å	Cell parameters from 6070 reflections
c = 8.9414 (11) Å	θ = 2.8–27.5°
α = 86.927 (6)°	µ = 0.72 mm^−1
β = 80.354 (6)°	T = 173 K
γ = 72.587 (5)°	Plate, colourless
V = 455.38 (10) Å^3	0.23 × 0.22 × 0.04 mm

Data collection

Bruker APEXII CCD diffractometer	1972 reflections with I > 2σ(I)
φ and ω scans	Rint = 0.023
Absorption correction: multi-scan (SADABS; Bruker, 2014)	θmax = 27.5°, θmin = 2.3°
Tmin = 0.690, Tmax = 0.746	h = −9→8
8052 measured reflections	k = −9→9
2092 independent reflections	l = −10→11

Refinement

Refinement on F^2	0 restraints
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.028	H-atom parameters constrained
wR(F^2) = 0.076	w = 1/[σ^2(Fo^2) + (0.0371P)^2 + 0.2062P] where P = (Fo^2 + 2Fc^2)/3
S = 1.12	(Δ/σ)max < 0.001
2092 reflections	Δρmax = 0.29 e Å^−3
137 parameters	Δρmin = −0.38 e Å^−3

Special details

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.

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

	x	y	z	Uiso*/Ueq
Cl1	0.43701 (6)	0.90760 (5)	−0.32138 (4)	0.02990 (12)
Cl2	0.09018 (6)	1.29195 (5)	0.19394 (4)	0.02692 (11)
F1	0.37852 (14)	0.60390 (12)	−0.12163 (11)	0.0298 (2)
O1	0.08333 (16)	0.93076 (14)	0.31061 (11)	0.0234 (2)
O2	0.41952 (15)	0.68493 (14)	0.39455 (11)	0.0225 (2)
O3	0.24193 (16)	0.50096 (15)	0.50373 (13)	0.0278 (2)
H3	0.3515	0.4408	0.5295	0.042*
N1	0.23296 (18)	0.76320 (16)	0.09169 (14)	0.0202 (2)
N2	0.2865 (2)	1.24580 (17)	−0.12976 (14)	0.0244 (3)
H2A	0.2414	1.3515	−0.0813	0.029*
H2B	0.3429	1.2417	−0.2255	0.029*
C1	0.3133 (2)	0.76709 (19)	−0.05118 (17)	0.0202 (3)
C2	0.3356 (2)	0.91926 (19)	−0.13244 (15)	0.0192 (3)
C3	0.26931 (19)	1.08983 (18)	−0.05718 (15)	0.0177 (3)
C4	0.1811 (2)	1.08826 (18)	0.09480 (15)	0.0176 (3)
C5	0.16793 (19)	0.92352 (19)	0.16331 (15)	0.0178 (3)
C6	0.0683 (2)	0.7624 (2)	0.38160 (17)	0.0242 (3)
H6A	0.0248	0.6917	0.3114	0.029*
H6B	−0.0345	0.7900	0.4736	0.029*
C7	0.2634 (2)	0.64680 (19)	0.42518 (15)	0.0197 (3)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl1	0.0345 (2)	0.0351 (2)	0.01671 (18)	−0.00767 (16)	0.00124 (14)	−0.00224 (14)
Cl2	0.0359 (2)	0.01784 (17)	0.02395 (19)	−0.00397 (14)	−0.00232 (14)	−0.00355 (13)
F1	0.0372 (5)	0.0182 (4)	0.0318 (5)	−0.0048 (4)	−0.0035 (4)	−0.0076 (4)
O1	0.0270 (5)	0.0214 (5)	0.0177 (5)	−0.0044 (4)	0.0008 (4)	0.0058 (4)
O2	0.0245 (5)	0.0241 (5)	0.0208 (5)	−0.0101 (4)	−0.0048 (4)	0.0060 (4)
O3	0.0243 (5)	0.0232 (5)	0.0355 (6)	−0.0081 (4)	−0.0051 (5)	0.0130 (4)
N1	0.0209 (6)	0.0169 (5)	0.0232 (6)	−0.0058 (4)	−0.0055 (5)	0.0035 (4)
N2	0.0318 (7)	0.0200 (6)	0.0216 (6)	−0.0103 (5)	−0.0013 (5)	0.0055 (5)
C1	0.0195 (6)	0.0167 (6)	0.0242 (7)	−0.0035 (5)	−0.0058 (5)	−0.0025 (5)
C2	0.0190 (6)	0.0226 (7)	0.0158 (6)	−0.0060 (5)	−0.0025 (5)	−0.0002 (5)
C3	0.0170 (6)	0.0189 (6)	0.0183 (6)	−0.0065 (5)	−0.0053 (5)	0.0037 (5)
C4	0.0186 (6)	0.0155 (6)	0.0181 (6)	−0.0038 (5)	−0.0035 (5)	0.0002 (5)
C5	0.0150 (6)	0.0200 (6)	0.0173 (6)	−0.0036 (5)	−0.0037 (5)	0.0033 (5)
C6	0.0236 (7)	0.0258 (7)	0.0218 (7)	−0.0081 (6)	−0.0014 (5)	0.0090 (6)
C7	0.0252 (7)	0.0202 (6)	0.0132 (6)	−0.0073 (5)	−0.0005 (5)	0.0007 (5)

Geometric parameters (Å, º)

Cl1—C2	1.7181 (14)	N2—C3	1.3506 (17)
Cl2—C4	1.7216 (14)	N2—H2A	0.8800
F1—C1	1.3403 (16)	N2—H2B	0.8800
O1—C5	1.3499 (17)	C1—C2	1.370 (2)
O1—C6	1.4243 (17)	C2—C3	1.4080 (19)
O2—C7	1.2143 (17)	C3—C4	1.3990 (19)
O3—C7	1.3158 (17)	C4—C5	1.3877 (19)
O3—H3	0.8400	C6—C7	1.505 (2)
N1—C1	1.3117 (19)	C6—H6A	0.9900
N1—C5	1.3268 (18)	C6—H6B	0.9900
C5—O1—C6	117.32 (11)	C5—C4—C3	119.78 (12)
C7—O3—H3	109.5	C5—C4—Cl2	121.01 (11)
C1—N1—C5	116.03 (12)	C3—C4—Cl2	119.20 (10)
C3—N2—H2A	120.0	N1—C5—O1	119.54 (12)
C3—N2—H2B	120.0	N1—C5—C4	123.51 (13)
H2A—N2—H2B	120.0	O1—C5—C4	116.96 (12)
N1—C1—F1	115.22 (12)	O1—C6—C7	112.12 (12)
N1—C1—C2	126.49 (13)	O1—C6—H6A	109.2
F1—C1—C2	118.29 (13)	C7—C6—H6A	109.2
C1—C2—C3	118.00 (13)	O1—C6—H6B	109.2
C1—C2—Cl1	122.11 (11)	C7—C6—H6B	109.2
C3—C2—Cl1	119.88 (10)	H6A—C6—H6B	107.9
N2—C3—C4	122.43 (12)	O2—C7—O3	124.35 (13)
N2—C3—C2	121.39 (12)	O2—C7—C6	124.46 (13)
C4—C3—C2	116.17 (12)	O3—C7—C6	111.18 (12)
C5—N1—C1—F1	179.85 (11)	C2—C3—C4—Cl2	−178.35 (10)
C5—N1—C1—C2	−0.2 (2)	C1—N1—C5—O1	179.97 (12)
N1—C1—C2—C3	0.9 (2)	C1—N1—C5—C4	0.1 (2)
F1—C1—C2—C3	−179.10 (12)	C6—O1—C5—N1	−0.13 (18)
N1—C1—C2—Cl1	−178.05 (11)	C6—O1—C5—C4	179.71 (12)
F1—C1—C2—Cl1	1.94 (19)	C3—C4—C5—N1	−0.9 (2)
C1—C2—C3—N2	179.92 (13)	Cl2—C4—C5—N1	179.01 (10)
Cl1—C2—C3—N2	−1.09 (18)	C3—C4—C5—O1	179.27 (11)
C1—C2—C3—C4	−1.55 (19)	Cl2—C4—C5—O1	−0.82 (17)
Cl1—C2—C3—C4	177.43 (10)	C5—O1—C6—C7	78.48 (15)
N2—C3—C4—C5	−179.93 (12)	O1—C6—C7—O2	−4.9 (2)
C2—C3—C4—C5	1.56 (19)	O1—C6—C7—O3	173.75 (12)
N2—C3—C4—Cl2	0.16 (18)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3···O2^i	0.84	1.84	2.6801 (15)	174
N2—H2A···F1^ii	0.88	2.39	2.9950 (15)	126
N2—H2B···O2^iii	0.88	2.25	3.0201 (16)	146

Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) x, y+1, z; (iii) −x+1, −y+2, −z.