organic compounds
Ammonium hydrogen bis[(3-chloro-2-methylphenoxy)acetate]
aScience and Engineering Faculty, Queensland University of Technology, GPO Box 2434, Brisbane, Queensland 4001, Australia
*Correspondence e-mail: gsmith@bigpond.com
In the structure of the ammonium hydrogen salt of (3-chloro-2-methylphenoxy)acetic acid, NH4+·C18H17Cl2O6−, the dimeric anion comprises two inversion-related head-to-head components linked through a short symmetric carboxyl O⋯H⋯O hydrogen bond in which the delocalized acid H atom lies on an inversion centre. The ammonium cation is disordered over another inversion centre. The is based on a number of inter-species ammonium N—H⋯O hydrogen-bonding associations, giving two-dimensional layers lying parallel to (001).
Keywords: crystal structure; phenoxyacetic acids; (3-chloro-4-methylphenoxy)acetic acid; ammonium carboxylates; hydrogen bonding.
CCDC reference: 1570335
Structure description
The phenoxyacetic acid analogues comprise an important group of chemicals, among which there are a number of herbicidally active commercial herbicides, including the ring-substituted members [2,4-dichloro- (2,4-D), 2,4,5-trichloro- (2,4,5-T) and 4-chloro-2-methyl- (MCPA)] (Zimdahl, 2010). The crystal structures of a large number of these acid analogs and their metal complexes are known, but the ammonium salts of only a small number have been reported, namely the hemihydrates, with 2,4-D (Liu et al., 2009), with MCPA (Smith, 2014) and with (3,5-dichlorophenoxy)acetic acid (Smith, 2015), and the anhydrous salts with the parent phenoxyacetic acid and (4-fluorophenoxy)acetic acid (Smith, 2014). In these structures, the presence of characteristic two-dimensional hydrogen-bonded nets are found, predicted by Odendal et al. (2010) for ammonium salts of this type of monocarboxylic acid. Herein is reported the structure of the anhydrous ammonium hydrogen salt of (3-chloro-2-methylphenoxy)acetic acid, NH4+·C18H17Cl2O6−.
In the structure of the title salt, the dimeric monoanionic species is unusual in that it comprises two inversion-related components which are linked through a single delocalized carboxyl proton (H14) lying on the inversion centre at (1, 1, 0) in a short O14⋯H⋯O14i hydrogen bond [2.493 (3) Å] (Fig. 1 and Table 1). This type of symmetric interaction (Type A) is found in the early reported potassium and rubidium hydrogen salts of 2-nitrobenzoic acid (Shrivastava & Speakman, 1961) and although no other ammonium phenoxyacetates of this type are known (Smith, 2014, 2015), the caesium–2,4-D structure has a coordinated hydrogen bis[(2,4-dichlorophenoxy)acetic acid)] ligand species, with O⋯H⋯O = 2.449 (4) Å (Smith & Lynch, 2014). Other examples of ammonium and alkali metal hydrogen bis(monocarboxylates) are known, including those in which the acid H atom is disordered within the short hydrogen bond (equivalent to a 1:1:1 cation–anion–acid adduct) (Type B), e.g. ammonium hydrogen bis(3-bromocinnamate) (Chowdhury & Kariuki, 2006) and potassium hydrogen bis(4-nitrobenzoate) (Shrivastava & Speakman, 1961).
The H atoms of the ammonium anion are disordered over an inversion centre at N1 (0, , 0) and are related by symmetry code (−x, −y + 1, −z). These atoms are involved in hydrogen-bonding interactions with phenoxy and carboxyl O-atom acceptors (Table 1), giving an overall two-dimensional layered structure which lies parallel to (001) (Fig. 2). This is also similar to the predicted two-dimensional layered structures in the other ammonium phenoxyacetates (Smith, 2014; 2015), as predicted by Odendal et al. (2010).
The phenoxyacetate species are essentially planar with the comparative defining torsion angles in the oxoacetate side chain, viz. C2—C1—O11—C12, C1—O11—C12—C13 and O11—C12—C13—O14 of −174.3 (2), 171.5 (2) and −179.3 (2)°, respectively. This planarity is also found in the parent acid (Smith, 2013) and in the majority of the phenoxyacetic acids, an exception being the 2,4-D structure (Smith et al., 1976), in which the oxoacetic acid side chain adopts a synclinal conformation.
Synthesis and crystallization
The title compound was prepared by the addition of excess 5 M aqueous ammonia solution to 1 mmol of (3-chloro-2-methylphenoxy)acetic acid (200 mg) in 10 ml of 10% ethanol–water. Room-temperature evaporation of the solvent gave small colourless single-crystal plates suitable for the X-ray analysis.
Refinement
Crystal data, data collection and structure . The H atoms of the 50% disordered ammonium cation centred at (0, , 0) were located by difference methods and were included in the refinements with N—H bond-length restraints and with their isotropic displacement parameters riding and Uiso(H) = 1.2Ueq(N1). Carboxyl atom H14 was located at (1,1,0) and constrained in the with the displacement parameter allowed to ride, and Ueq(H) = 1.5Ueq(O14). The methyl group was found to be rotationally disordered, with H atoms split over six equivalent half-sites and was treated accordingly.
details are summarized in Table 2
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Structural data
CCDC reference: 1570335
https://doi.org/10.1107/S2414314617012238/bh4026sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314617012238/bh4026Isup2.hkl
Supporting information file. DOI: https://doi.org/10.1107/S2414314617012238/bh4026Isup3.cml
Data collection: CrysAlis PRO (Rigaku OD, 2015); cell
CrysAlis PRO (Rigaku OD, 2015); data reduction: CrysAlis PRO (Rigaku OD, 2015); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008) within WinGX (Farrugia, 2012); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: PLATON (Spek, 2009).NH4+·C18H17Cl2O6− | Z = 1 |
Mr = 418.26 | F(000) = 218 |
Triclinic, P1 | Dx = 1.490 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 4.7434 (5) Å | Cell parameters from 818 reflections |
b = 6.8568 (8) Å | θ = 3.7–26.9° |
c = 15.0374 (15) Å | µ = 0.38 mm−1 |
α = 100.880 (9)° | T = 200 K |
β = 92.184 (8)° | Prism, colourless |
γ = 103.053 (9)° | 0.22 × 0.10 × 0.08 mm |
V = 466.21 (9) Å3 |
Oxford Diffraction Gemini-S CCD-detector diffractometer | 1834 independent reflections |
Radiation source: Enhance (Mo) X-ray source | 1444 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.026 |
Detector resolution: 16.077 pixels mm-1 | θmax = 26.0°, θmin = 3.1° |
ω scans | h = −5→5 |
Absorption correction: multi-scan (CrysAlis PRO; Rigaku OD, 2015) | k = −4→8 |
Tmin = 0.92, Tmax = 0.98 | l = −18→17 |
2774 measured reflections |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.052 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.113 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.05 | w = 1/[σ2(Fo2) + (0.0364P)2 + 0.3125P] where P = (Fo2 + 2Fc2)/3 |
1834 reflections | (Δ/σ)max < 0.001 |
137 parameters | Δρmax = 0.25 e Å−3 |
4 restraints | Δρmin = −0.28 e Å−3 |
0 constraints |
x | y | z | Uiso*/Ueq | Occ. (<1) | |
Cl3 | −0.46252 (18) | 0.64679 (12) | 0.40172 (5) | 0.0414 (3) | |
O11 | 0.2641 (4) | 0.8709 (3) | 0.18193 (12) | 0.0249 (6) | |
O13 | 0.5974 (4) | 0.7439 (3) | 0.05330 (13) | 0.0294 (7) | |
O14 | 0.8485 (4) | 1.0668 (3) | 0.05893 (13) | 0.0290 (6) | |
C1 | 0.1228 (5) | 0.9334 (4) | 0.25666 (17) | 0.0219 (8) | |
C2 | −0.0737 (6) | 0.7757 (4) | 0.28509 (17) | 0.0227 (8) | |
C3 | −0.2187 (6) | 0.8335 (4) | 0.35999 (18) | 0.0264 (9) | |
C4 | −0.1806 (6) | 1.0340 (4) | 0.40595 (18) | 0.0291 (9) | |
C5 | 0.0156 (6) | 1.1828 (4) | 0.37604 (19) | 0.0288 (9) | |
C6 | 0.1685 (6) | 1.1348 (4) | 0.30177 (18) | 0.0243 (8) | |
C12 | 0.4836 (6) | 1.0238 (4) | 0.15668 (18) | 0.0225 (8) | |
C13 | 0.6498 (6) | 0.9288 (4) | 0.08328 (18) | 0.0231 (8) | |
C21 | −0.1208 (6) | 0.5589 (4) | 0.23503 (19) | 0.0307 (9) | |
N1 | 0.00000 | 0.50000 | 0.00000 | 0.0293 (11) | |
H4 | −0.28680 | 1.06740 | 0.45660 | 0.0350* | |
H5 | 0.04680 | 1.32120 | 0.40690 | 0.0350* | |
H6 | 0.30380 | 1.23920 | 0.28190 | 0.0290* | |
H14 | 1.00000 | 1.00000 | 0.00000 | 0.0440* | |
H121 | 0.61900 | 1.09700 | 0.21050 | 0.0270* | |
H122 | 0.39400 | 1.12430 | 0.13420 | 0.0270* | |
H211 | −0.22140 | 0.46680 | 0.27240 | 0.0460* | 0.500 |
H212 | 0.06720 | 0.52810 | 0.22220 | 0.0460* | 0.500 |
H213 | −0.23900 | 0.53980 | 0.17780 | 0.0460* | 0.500 |
H214 | 0.03810 | 0.54390 | 0.19660 | 0.0460* | 0.500 |
H215 | −0.11590 | 0.46310 | 0.27650 | 0.0460* | 0.500 |
H216 | −0.31780 | 0.51360 | 0.20050 | 0.0460* | 0.500 |
H10 | −0.187 (7) | 0.422 (8) | −0.022 (4) | 0.0270* | 0.500 |
H11 | 0.140 (11) | 0.429 (8) | −0.022 (4) | 0.0270* | 0.500 |
H12 | 0.017 (14) | 0.565 (8) | 0.0609 (17) | 0.0270* | 0.500 |
H13 | 0.052 (13) | 0.610 (6) | −0.029 (4) | 0.0270* | 0.500 |
U11 | U22 | U33 | U12 | U13 | U23 | |
Cl3 | 0.0468 (5) | 0.0320 (4) | 0.0378 (4) | −0.0076 (3) | 0.0184 (3) | 0.0056 (3) |
O11 | 0.0233 (10) | 0.0210 (10) | 0.0293 (10) | 0.0033 (8) | 0.0108 (8) | 0.0028 (8) |
O13 | 0.0264 (11) | 0.0231 (11) | 0.0389 (12) | 0.0086 (8) | 0.0082 (8) | 0.0025 (9) |
O14 | 0.0236 (10) | 0.0289 (11) | 0.0373 (12) | 0.0067 (8) | 0.0120 (9) | 0.0110 (9) |
C1 | 0.0194 (13) | 0.0247 (14) | 0.0225 (14) | 0.0079 (11) | 0.0031 (11) | 0.0038 (11) |
C2 | 0.0239 (14) | 0.0198 (14) | 0.0240 (14) | 0.0045 (11) | 0.0003 (11) | 0.0047 (11) |
C3 | 0.0233 (15) | 0.0262 (15) | 0.0278 (15) | −0.0002 (12) | 0.0049 (11) | 0.0079 (12) |
C4 | 0.0298 (16) | 0.0288 (16) | 0.0261 (15) | 0.0049 (12) | 0.0087 (12) | 0.0005 (12) |
C5 | 0.0311 (16) | 0.0209 (15) | 0.0311 (15) | 0.0050 (12) | 0.0033 (12) | −0.0013 (12) |
C6 | 0.0229 (14) | 0.0187 (14) | 0.0290 (15) | 0.0008 (11) | 0.0061 (11) | 0.0031 (11) |
C12 | 0.0203 (13) | 0.0182 (14) | 0.0271 (14) | 0.0014 (10) | 0.0040 (11) | 0.0032 (11) |
C13 | 0.0197 (14) | 0.0254 (15) | 0.0264 (15) | 0.0090 (11) | 0.0015 (11) | 0.0065 (12) |
C21 | 0.0373 (17) | 0.0204 (15) | 0.0327 (16) | 0.0028 (12) | 0.0080 (13) | 0.0050 (12) |
N1 | 0.0224 (19) | 0.028 (2) | 0.034 (2) | 0.0121 (16) | −0.0011 (15) | −0.0093 (16) |
Cl3—C3 | 1.749 (3) | C4—C5 | 1.373 (4) |
O11—C1 | 1.379 (3) | C5—C6 | 1.383 (4) |
O11—C12 | 1.419 (3) | C12—C13 | 1.514 (4) |
O13—C13 | 1.227 (3) | C4—H4 | 0.9500 |
O14—C13 | 1.293 (3) | C5—H5 | 0.9500 |
O14—H14 | 1.2500 | C6—H6 | 0.9500 |
N1—H12 | 0.93 (3) | C12—H122 | 0.9900 |
N1—H10 | 0.94 (4) | C12—H121 | 0.9900 |
N1—H11 | 0.94 (5) | C21—H212 | 0.9800 |
N1—H13 | 0.93 (5) | C21—H213 | 0.9800 |
C1—C2 | 1.404 (4) | C21—H211 | 0.9800 |
C1—C6 | 1.384 (4) | C21—H215 | 0.9900 |
C2—C21 | 1.497 (4) | C21—H216 | 1.0100 |
C2—C3 | 1.383 (4) | C21—H214 | 0.9800 |
C3—C4 | 1.386 (4) | ||
C1—O11—C12 | 116.2 (2) | C3—C4—H4 | 121.00 |
C13—O14—H14 | 115.00 | C5—C4—H4 | 121.00 |
H10—N1—H11 | 110 (5) | C4—C5—H5 | 119.00 |
H10—N1—H12 | 115 (5) | C6—C5—H5 | 119.00 |
H10—N1—H13 | 111 (5) | C5—C6—H6 | 120.00 |
H12—N1—H13 | 102 (5) | C1—C6—H6 | 120.00 |
H11—N1—H12 | 120 (5) | O11—C12—H121 | 110.00 |
H11—N1—H13 | 98 (5) | O11—C12—H122 | 110.00 |
O11—C1—C6 | 123.7 (2) | C13—C12—H121 | 110.00 |
O11—C1—C2 | 114.9 (2) | C13—C12—H122 | 110.00 |
C2—C1—C6 | 121.5 (2) | H121—C12—H122 | 108.00 |
C1—C2—C21 | 120.6 (2) | H214—C21—H215 | 104.00 |
C1—C2—C3 | 116.3 (2) | H214—C21—H216 | 113.00 |
C3—C2—C21 | 123.2 (2) | H215—C21—H216 | 107.00 |
Cl3—C3—C4 | 116.8 (2) | C2—C21—H211 | 109.00 |
C2—C3—C4 | 123.7 (3) | C2—C21—H212 | 109.00 |
Cl3—C3—C2 | 119.5 (2) | C2—C21—H213 | 109.00 |
C3—C4—C5 | 117.9 (3) | C2—C21—H214 | 110.00 |
C4—C5—C6 | 121.2 (3) | C2—C21—H215 | 112.00 |
C1—C6—C5 | 119.5 (3) | C2—C21—H216 | 110.00 |
O11—C12—C13 | 110.4 (2) | H211—C21—H212 | 109.00 |
O13—C13—O14 | 126.3 (3) | H211—C21—H213 | 109.00 |
O14—C13—C12 | 111.1 (2) | H212—C21—H213 | 110.00 |
O13—C13—C12 | 122.6 (2) | ||
C12—O11—C1—C2 | −174.3 (2) | C1—C2—C3—C4 | 0.5 (4) |
C12—O11—C1—C6 | 5.3 (4) | C21—C2—C3—Cl3 | 1.9 (4) |
C1—O11—C12—C13 | 171.5 (2) | C21—C2—C3—C4 | −178.9 (3) |
O11—C1—C2—C3 | 179.9 (2) | Cl3—C3—C4—C5 | 178.3 (2) |
O11—C1—C2—C21 | −0.7 (4) | C2—C3—C4—C5 | −1.0 (4) |
C6—C1—C2—C3 | 0.3 (4) | C3—C4—C5—C6 | 0.7 (4) |
C6—C1—C2—C21 | 179.7 (3) | C4—C5—C6—C1 | 0.1 (4) |
O11—C1—C6—C5 | 179.8 (2) | O11—C12—C13—O13 | −1.3 (4) |
C2—C1—C6—C5 | −0.6 (4) | O11—C12—C13—O14 | 179.3 (2) |
C1—C2—C3—Cl3 | −178.7 (2) |
D—H···A | D—H | H···A | D···A | D—H···A |
O14—H14···O14i | 1.25 | 1.25 | 2.494 (3) | 180 |
O14—H14···O13i | 1.25 | 2.55 | 3.326 (3) | 118 |
N1—H10···O13ii | 0.94 (4) | 2.01 (4) | 2.941 (2) | 173 (6) |
N1—H11···O13iii | 0.94 (5) | 1.92 (5) | 2.853 (2) | 171 (5) |
N1—H12···O11 | 0.93 (3) | 2.52 (4) | 3.3458 (19) | 147 (4) |
N1—H13···O14iv | 0.93 (5) | 2.29 (4) | 3.194 (2) | 163 (5) |
C21—H211···Cl3 | 0.98 | 2.55 | 3.075 (3) | 113 |
C21—H214···O11 | 0.98 | 2.31 | 2.746 (3) | 106 |
Symmetry codes: (i) −x+2, −y+2, −z; (ii) −x, −y+1, −z; (iii) −x+1, −y+1, −z; (iv) −x+1, −y+2, −z. |
Acknowledgements
The author acknowledges support from the Science and Engineering Faculty, Queensland University of Technology.
References
Chowdhury, M. & Kariuki, B. M. (2006). Cryst. Growth Des. 6, 774–780. Web of Science CSD CrossRef CAS Google Scholar
Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849–854. Web of Science CrossRef CAS IUCr Journals Google Scholar
Liu, H.-L., Guo, S.-H., Li, Y.-Y. & Jian, F.-F. (2009). Acta Cryst. E65, o1905. Web of Science CSD CrossRef IUCr Journals Google Scholar
Odendal, J. A., Bruce, J. C., Koch, K. R. & Haynes, D. A. (2010). CrystEngComm, 12, 2398–2408. Web of Science CSD CrossRef CAS Google Scholar
Rigaku OD (2015). CrysAlis PRO. Rigaku Oxford Diffraction Ltd, Yarnton, Oxfordshire, England. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Shrivastava, H. N. & Speakman, J. C. (1961). J. Chem. Soc. A, pp. 1151–1163. Google Scholar
Smith, G. (2013). Private communication (deposition No. 965177). CCDC, Cambridge, England. Google Scholar
Smith, G. (2014). Acta Cryst. E70, 528–532. CSD CrossRef IUCr Journals Google Scholar
Smith, G. (2015). Acta Cryst. E71, o717–o718. CrossRef IUCr Journals Google Scholar
Smith, G., Kennard, C. H. L. & White, A. H. (1976). J. Chem. Soc. Perkin Trans. 2, pp. 791–792. CSD CrossRef Web of Science Google Scholar
Smith, G. & Lynch, D. E. (2014). Acta Cryst. C70, 606–612. Web of Science CSD CrossRef IUCr Journals Google Scholar
Spek, A. L. (2009). Acta Cryst. D65, 148–155. Web of Science CrossRef CAS IUCr Journals Google Scholar
Zimdahl, R. L. (2010). In A History of Weed Science in the United States. New York: Elsevier. Google Scholar
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