(2,3-Dimethyl­phen­oxy)acetic acid

The acetic acid substituent of the title compound, C₁₀H₁₂O₃, is coplanar with the 2,3-dimethyl­phen­oxy group. The crystal structure is stabilized by inter­molecular hydrogen-bond inter­actions.

Key indicators

• Single-crystal X-ray study
• T = 103 K
• Mean [sigma](C-C) = 0.001 Å
• R factor = 0.040
• wR factor = 0.119
• Data-to-parameter ratio = 20.4

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT063_ALERT_3_C Crystal Probably too Large for Beam Size .......       0.76 mm
PLAT066_ALERT_1_C Predicted and Reported Transmissions Identical .          ?
PLAT154_ALERT_1_C The su's on the Cell Angles are Equal  (x 10000)        100 Deg.
PLAT180_ALERT_3_C Check Cell Rounding: # of Values Ending with 0 =          4

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   4 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

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

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S1. Comment

Phenoxyacetic acids are well known herbicides. It is also known that indole-3-acetic acid promotes cell elongation in plants and was isolated from plants and this stimulated the search for other compounds of related structure. This created great interest in aryloxyacetic acids as potential plant growth regulators and large number of phenoxyacetic acids are used as herbicides. Phenoxyacetic acid is used as a precursor in antibiotic fermentations especially for penicillin V and is a main skeleton of plant growth regulators and herbicides. It is used as an intermediate for manufacturing dyes, pharmaceuticals, pesticides, fungicides. It is used in flavoring. A review on the genotoxicity of 4-chloro-2-methylphenoxyacetic acid is described. In view of the importance of the title compound, (I), C₁₀H₁₂O₃, the crystal structure is reported.

The acetic acid ligand of the title compound is in the plane of the 2,3-dimethylphenoxy group with a C7—O1—C1—C2 torsion angle of -178.60 (6)°.

Related literature

For related structures, see: Chandrasekhar & Pattabhi (1977); Kumar & Rao (1980, 1982); Smith et al. (1981, 1986); Kennard et al. (1981, 1982); Hegde et al. (1991); Cox & Hickey (2004); Byres & Cox (2007). For background, see: Cremlyn (1978 or???1979); Gruzdyev et al. (1983); Elliott (2005).

For related literature, see: Kennard & Smith (1981); Vogel (1989).

S2. Experimental

Title aryloxy acetic acid, C₁₀H₁₂O₃, (I), was prepared according to the literature method (Vogel, 1989) and was crystallized from acetone by slow evaporation (m.p.: 360 K).

S3. Refinement

All of the H atoms, except H2 which was located from difference Fourier map, were inferred from neighbouring sites. All H-atoms were included in the riding model approximation with C—H = 0.95–0.99 Å, and with U_iso(H) = 1.18–1.51U_eq(C).

Computing details

Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT; program(s) used to solve structure: SHELXS90 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 2000); software used to prepare material for publication: SHELXTL.

Figures

	Fig. 1. Molecular structure of C10H12O3, (I), showing atom labeling and 50% probability displacement ellipsoids.
	Fig. 2. Packing diagram of C10H12O3viewed down the b axis. Dashed lines indicate C—H···O hydrogen bonds between O2—H2 and O3 from inverted, in-plane adjacent molecules in the title compound.

(2,3-Dimethylphenoxy)acetic acid

Crystal data

C10H12O3	Z = 2
Mr = 180.20	F(000) = 192
Triclinic, P1	Dx = 1.359 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 6.7609 (6) Å	Cell parameters from 4023 reflections
b = 6.8452 (6) Å	θ = 0.0–0.0°
c = 10.783 (1) Å	µ = 0.10 mm^−1
α = 72.549 (1)°	T = 103 K
β = 81.202 (1)°	Prism, colorless
γ = 67.756 (1)°	0.76 × 0.58 × 0.32 mm
V = 440.20 (7) Å^3

Data collection

Bruker SMART CCD area-detector diffractometer	2463 independent reflections
Radiation source: fine-focus sealed tube	2321 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.015
φ and ω scans	θmax = 30.7°, θmin = 2.0°
Absorption correction: multi-scan (DENZO/SCALEPACK; Otwinowski & Minor, 1997)	h = −9→9
Tmin = 0.928, Tmax = 0.969	k = −9→7
4991 measured reflections	l = −14→15

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.040	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.119	H-atom parameters constrained
S = 1.03	w = 1/[σ^2(Fo^2) + (0.0769P)^2 + 0.1045P] where P = (Fo^2 + 2Fc^2)/3
2463 reflections	(Δ/σ)max = 0.013
121 parameters	Δρmax = 0.43 e Å^−3
0 restraints	Δρmin = −0.36 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
O1	0.40060 (9)	0.53274 (10)	0.17282 (6)	0.01580 (15)
O2	0.77872 (10)	0.74592 (10)	−0.02470 (6)	0.01806 (16)
H2	0.9099	0.6872	−0.0414	0.022*
O3	0.81153 (9)	0.40211 (10)	0.08982 (6)	0.01629 (16)
C1	0.19165 (12)	0.60157 (13)	0.22166 (8)	0.01308 (17)
C2	0.12308 (12)	0.43570 (13)	0.30554 (8)	0.01355 (17)
C21	0.27567 (14)	0.20182 (14)	0.33949 (9)	0.01978 (19)
H21A	0.2670	0.1386	0.4337	0.030*
H21B	0.4219	0.1979	0.3123	0.030*
H21C	0.2373	0.1170	0.2946	0.030*
C3	−0.08874 (13)	0.49346 (13)	0.35611 (8)	0.01427 (17)
C31	−0.17245 (14)	0.31989 (15)	0.44193 (9)	0.01932 (19)
H31A	−0.3247	0.3876	0.4639	0.029*
H31B	−0.0932	0.2491	0.5219	0.029*
H31C	−0.1538	0.2103	0.3957	0.029*
C4	−0.22446 (13)	0.71328 (14)	0.32598 (8)	0.01596 (18)
H4A	−0.3672	0.7520	0.3616	0.019*
C5	−0.15242 (13)	0.87504 (13)	0.24465 (8)	0.01634 (18)
H5A	−0.2455	1.0236	0.2257	0.020*
C6	0.05604 (13)	0.82050 (13)	0.19054 (8)	0.01513 (17)
H6A	0.1049	0.9304	0.1335	0.018*
C7	0.47291 (12)	0.69872 (13)	0.09072 (8)	0.01408 (17)
H7A	0.4546	0.8102	0.1367	0.017*
H7B	0.3879	0.7715	0.0119	0.017*
C8	0.70550 (12)	0.59811 (13)	0.05272 (8)	0.01343 (17)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0109 (3)	0.0134 (3)	0.0199 (3)	−0.0050 (2)	0.0046 (2)	−0.0017 (2)
O2	0.0144 (3)	0.0151 (3)	0.0233 (3)	−0.0077 (2)	0.0051 (2)	−0.0028 (2)
O3	0.0143 (3)	0.0143 (3)	0.0191 (3)	−0.0060 (2)	0.0017 (2)	−0.0027 (2)
C1	0.0110 (3)	0.0136 (4)	0.0142 (3)	−0.0048 (3)	0.0019 (3)	−0.0038 (3)
C2	0.0127 (3)	0.0131 (3)	0.0142 (3)	−0.0050 (3)	0.0018 (3)	−0.0032 (3)
C21	0.0184 (4)	0.0130 (4)	0.0222 (4)	−0.0033 (3)	0.0044 (3)	−0.0021 (3)
C3	0.0137 (3)	0.0161 (4)	0.0136 (3)	−0.0071 (3)	0.0022 (3)	−0.0038 (3)
C31	0.0177 (4)	0.0185 (4)	0.0214 (4)	−0.0099 (3)	0.0056 (3)	−0.0034 (3)
C4	0.0121 (3)	0.0176 (4)	0.0169 (4)	−0.0045 (3)	0.0023 (3)	−0.0051 (3)
C5	0.0140 (4)	0.0140 (4)	0.0181 (4)	−0.0028 (3)	0.0006 (3)	−0.0036 (3)
C6	0.0142 (3)	0.0131 (4)	0.0167 (4)	−0.0054 (3)	0.0015 (3)	−0.0022 (3)
C7	0.0118 (3)	0.0131 (3)	0.0166 (4)	−0.0060 (3)	0.0023 (3)	−0.0025 (3)
C8	0.0129 (3)	0.0152 (4)	0.0138 (3)	−0.0069 (3)	0.0012 (3)	−0.0047 (3)

Geometric parameters (Å, º)

O1—C1	1.3829 (9)	C3—C31	1.5092 (11)
O1—C7	1.4136 (9)	C31—H31A	0.9800
O2—C8	1.3084 (10)	C31—H31B	0.9800
O2—H2	0.8400	C31—H31C	0.9800
O3—C8	1.2295 (10)	C4—C5	1.3884 (11)
C1—C6	1.3969 (11)	C4—H4A	0.9500
C1—C2	1.4059 (11)	C5—C6	1.3953 (11)
C2—C3	1.4022 (11)	C5—H5A	0.9500
C2—C21	1.5083 (11)	C6—H6A	0.9500
C21—H21A	0.9800	C7—C8	1.5057 (11)
C21—H21B	0.9800	C7—H7A	0.9900
C21—H21C	0.9800	C7—H7B	0.9900
C3—C4	1.4015 (11)
C1—O1—C7	116.00 (6)	H31A—C31—H31C	109.5
C8—O2—H2	109.5	H31B—C31—H31C	109.5
O1—C1—C6	122.84 (7)	C5—C4—C3	120.66 (7)
O1—C1—C2	115.49 (7)	C5—C4—H4A	119.7
C6—C1—C2	121.68 (7)	C3—C4—H4A	119.7
C3—C2—C1	118.45 (7)	C4—C5—C6	120.34 (7)
C3—C2—C21	121.37 (7)	C4—C5—H5A	119.8
C1—C2—C21	120.18 (7)	C6—C5—H5A	119.8
C2—C21—H21A	109.5	C5—C6—C1	118.89 (7)
C2—C21—H21B	109.5	C5—C6—H6A	120.6
H21A—C21—H21B	109.5	C1—C6—H6A	120.6
C2—C21—H21C	109.5	O1—C7—C8	109.13 (6)
H21A—C21—H21C	109.5	O1—C7—H7A	109.9
H21B—C21—H21C	109.5	C8—C7—H7A	109.9
C4—C3—C2	119.94 (7)	O1—C7—H7B	109.9
C4—C3—C31	119.68 (7)	C8—C7—H7B	109.9
C2—C3—C31	120.38 (7)	H7A—C7—H7B	108.3
C3—C31—H31A	109.5	O3—C8—O2	124.77 (7)
C3—C31—H31B	109.5	O3—C8—C7	124.00 (7)
H31A—C31—H31B	109.5	O2—C8—C7	111.23 (7)
C3—C31—H31C	109.5
C7—O1—C1—C6	1.44 (12)	C2—C3—C4—C5	1.00 (12)
C7—O1—C1—C2	−178.60 (6)	C31—C3—C4—C5	−178.41 (7)
O1—C1—C2—C3	−178.50 (7)	C3—C4—C5—C6	0.67 (13)
C6—C1—C2—C3	1.46 (12)	C4—C5—C6—C1	−1.25 (13)
O1—C1—C2—C21	1.53 (12)	O1—C1—C6—C5	−179.87 (7)
C6—C1—C2—C21	−178.51 (7)	C2—C1—C6—C5	0.18 (13)
C1—C2—C3—C4	−2.03 (12)	C1—O1—C7—C8	176.74 (6)
C21—C2—C3—C4	177.94 (7)	O1—C7—C8—O3	−0.52 (11)
C1—C2—C3—C31	177.38 (7)	O1—C7—C8—O2	179.29 (6)
C21—C2—C3—C31	−2.65 (12)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2···O3^i	0.84	1.79	2.6269 (9)	172

Symmetry code: (i) −x+2, −y+1, −z.