organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Journal logoIUCrDATA
ISSN: 2414-3146

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

Edited by S. Bernès, Benemérita Universidad Autónoma de Puebla, México (Received 29 June 2017; accepted 23 August 2017; online 30 August 2017)

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 crystal structure is based on a number of inter-species ammonium N—H⋯O hydrogen-bonding associations, giving two-dimensional layers lying parallel to (001).

3D view (loading...)
[Scheme 3D1]
Chemical scheme
[Scheme 1]

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[Zimdahl, R. L. (2010). In A History of Weed Science in the United States. New York: Elsevier.]). 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[Liu, H.-L., Guo, S.-H., Li, Y.-Y. & Jian, F.-F. (2009). Acta Cryst. E65, o1905.]), with MCPA (Smith, 2014[Smith, G. (2014). Acta Cryst. E70, 528-532.]) and with (3,5-di­chloro­phen­oxy)acetic acid (Smith, 2015[Smith, G. (2015). Acta Cryst. E71, o717-o718.]), and the anhydrous salts with the parent phen­oxy­acetic acid and (4-fluoro­phen­oxy)acetic acid (Smith, 2014[Smith, G. (2014). Acta Cryst. E70, 528-532.]). In these structures, the presence of characteristic two-dimensional hydrogen-bonded nets are found, predicted by Odendal et al. (2010[Odendal, J. A., Bruce, J. C., Koch, K. R. & Haynes, D. A. (2010). CrystEngComm, 12, 2398-2408.]) 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[link] and Table 1[link]). 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[Shrivastava, H. N. & Speakman, J. C. (1961). J. Chem. Soc. A, pp. 1151-1163.]) and although no other ammonium phen­oxy­acetates of this type are known (Smith, 2014[Smith, G. (2014). Acta Cryst. E70, 528-532.], 2015[Smith, G. (2015). Acta Cryst. E71, o717-o718.]), 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[Smith, G. & Lynch, D. E. (2014). Acta Cryst. C70, 606-612.]). 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[Chowdhury, M. & Kariuki, B. M. (2006). Cryst. Growth Des. 6, 774-780.]) and potassium hydrogen bis­(4-nitro­benzoate) (Shrivastava & Speakman, 1961[Shrivastava, H. N. & Speakman, J. C. (1961). J. Chem. Soc. A, pp. 1151-1163.]).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA 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)
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.
[Figure 1]
Figure 1
The mol­ecular conformation and atom-numbering scheme for the title salt, with displacement ellipsoids drawn at the 50% probability level. The inter-species H atom (H14) and the ammonium cation are disordered over inversion centres, with the two phen­oxy species related by the symmetry code (i) −x + 2, −y + 2, −z. H atoms of one disorder component of the rotationally disordered methyl group are not shown.

The H atoms of the ammonium anion are disordered over an inversion centre at N1 (0, [1 \over 2], 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[link]), giving an overall two-dimensional layered structure which lies parallel to (001) (Fig. 2[link]). This is also similar to the predicted two-dimensional layered structures in the other ammonium phen­oxy­acetates (Smith, 2014[Smith, G. (2014). Acta Cryst. E70, 528-532.]; 2015[Smith, G. (2015). Acta Cryst. E71, o717-o718.]), as predicted by Odendal et al. (2010[Odendal, J. A., Bruce, J. C., Koch, K. R. & Haynes, D. A. (2010). CrystEngComm, 12, 2398-2408.]).

[Figure 2]
Figure 2
A perspective view of a portion of the two-dimensional hydrogen-bonded network structure of the title salt, with hydrogen bonds shown as dashed lines. Non-associative hydrogen bonds are not shown. For symmetry codes, see Table 1[link].

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[Smith, G. (2013). Private communication (deposition No. 965177). CCDC, Cambridge, England.]) and in the majority of the phen­oxy­acetic acids, an exception being the 2,4-D structure (Smith et al., 1976[Smith, G., Kennard, C. H. L. & White, A. H. (1976). J. Chem. Soc. Perkin Trans. 2, pp. 791-792.]), 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 refinement details are summarized in Table 2[link]. The H atoms of the 50% disordered ammonium cation centred at (0, [1 \over 2], 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 refinement, 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.

Table 2
Experimental details

Crystal data
Chemical formula NH4+·C18H17Cl2O6
Mr 418.26
Crystal system, space group Triclinic, P[\overline{1}]
Temperature (K) 200
a, b, c (Å) 4.7434 (5), 6.8568 (8), 15.0374 (15)
α, β, γ (°) 100.880 (9), 92.184 (8), 103.053 (9)
V3) 466.21 (9)
Z 1
Radiation type Mo Kα
μ (mm−1) 0.38
Crystal size (mm) 0.22 × 0.10 × 0.08
 
Data collection
Diffractometer Oxford Diffraction Gemini-S CCD-detector
Absorption correction Multi-scan (CrysAlis PRO; Rigaku OD, 2015[Rigaku OD (2015). CrysAlis PRO. Rigaku Oxford Diffraction Ltd, Yarnton, Oxfordshire, England.])
Tmin, Tmax 0.92, 0.98
No. of measured, independent and observed [I > 2σ(I)] reflections 2774, 1834, 1444
Rint 0.026
(sin θ/λ)max−1) 0.617
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.052, 0.113, 1.05
No. of reflections 1834
No. of parameters 137
No. of restraints 4
H-atom treatment H atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3) 0.25, −0.28
Computer programs: CrysAlis PRO (Rigaku OD, 2015[Rigaku OD (2015). CrysAlis PRO. Rigaku Oxford Diffraction Ltd, Yarnton, Oxfordshire, England.]), SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]), SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]) within WinGX (Farrugia, 2012[Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849-854.]) and PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]).

Structural data


Computing details top

Data collection: CrysAlis PRO (Rigaku OD, 2015); cell refinement: 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).

Ammonium hydrogen bis[(3-chloro-2-methylphenoxy)acetate] top
Crystal data top
NH4+·C18H17Cl2O6Z = 1
Mr = 418.26F(000) = 218
Triclinic, P1Dx = 1.490 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 4.7434 (5) ÅCell parameters from 818 reflections
b = 6.8568 (8) Åθ = 3.7–26.9°
c = 15.0374 (15) ŵ = 0.38 mm1
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
Data collection top
Oxford Diffraction Gemini-S CCD-detector
diffractometer
1834 independent reflections
Radiation source: Enhance (Mo) X-ray source1444 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.026
Detector resolution: 16.077 pixels mm-1θmax = 26.0°, θmin = 3.1°
ω scansh = 55
Absorption correction: multi-scan
(CrysAlis PRO; Rigaku OD, 2015)
k = 48
Tmin = 0.92, Tmax = 0.98l = 1817
2774 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.052Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.113H 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 parametersΔρmax = 0.25 e Å3
4 restraintsΔρmin = 0.28 e Å3
0 constraints
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
Cl30.46252 (18)0.64679 (12)0.40172 (5)0.0414 (3)
O110.2641 (4)0.8709 (3)0.18193 (12)0.0249 (6)
O130.5974 (4)0.7439 (3)0.05330 (13)0.0294 (7)
O140.8485 (4)1.0668 (3)0.05893 (13)0.0290 (6)
C10.1228 (5)0.9334 (4)0.25666 (17)0.0219 (8)
C20.0737 (6)0.7757 (4)0.28509 (17)0.0227 (8)
C30.2187 (6)0.8335 (4)0.35999 (18)0.0264 (9)
C40.1806 (6)1.0340 (4)0.40595 (18)0.0291 (9)
C50.0156 (6)1.1828 (4)0.37604 (19)0.0288 (9)
C60.1685 (6)1.1348 (4)0.30177 (18)0.0243 (8)
C120.4836 (6)1.0238 (4)0.15668 (18)0.0225 (8)
C130.6498 (6)0.9288 (4)0.08328 (18)0.0231 (8)
C210.1208 (6)0.5589 (4)0.23503 (19)0.0307 (9)
N10.000000.500000.000000.0293 (11)
H40.286801.067400.456600.0350*
H50.046801.321200.406900.0350*
H60.303801.239200.281900.0290*
H141.000001.000000.000000.0440*
H1210.619001.097000.210500.0270*
H1220.394001.124300.134200.0270*
H2110.221400.466800.272400.0460*0.500
H2120.067200.528100.222200.0460*0.500
H2130.239000.539800.177800.0460*0.500
H2140.038100.543900.196600.0460*0.500
H2150.115900.463100.276500.0460*0.500
H2160.317800.513600.200500.0460*0.500
H100.187 (7)0.422 (8)0.022 (4)0.0270*0.500
H110.140 (11)0.429 (8)0.022 (4)0.0270*0.500
H120.017 (14)0.565 (8)0.0609 (17)0.0270*0.500
H130.052 (13)0.610 (6)0.029 (4)0.0270*0.500
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cl30.0468 (5)0.0320 (4)0.0378 (4)0.0076 (3)0.0184 (3)0.0056 (3)
O110.0233 (10)0.0210 (10)0.0293 (10)0.0033 (8)0.0108 (8)0.0028 (8)
O130.0264 (11)0.0231 (11)0.0389 (12)0.0086 (8)0.0082 (8)0.0025 (9)
O140.0236 (10)0.0289 (11)0.0373 (12)0.0067 (8)0.0120 (9)0.0110 (9)
C10.0194 (13)0.0247 (14)0.0225 (14)0.0079 (11)0.0031 (11)0.0038 (11)
C20.0239 (14)0.0198 (14)0.0240 (14)0.0045 (11)0.0003 (11)0.0047 (11)
C30.0233 (15)0.0262 (15)0.0278 (15)0.0002 (12)0.0049 (11)0.0079 (12)
C40.0298 (16)0.0288 (16)0.0261 (15)0.0049 (12)0.0087 (12)0.0005 (12)
C50.0311 (16)0.0209 (15)0.0311 (15)0.0050 (12)0.0033 (12)0.0013 (12)
C60.0229 (14)0.0187 (14)0.0290 (15)0.0008 (11)0.0061 (11)0.0031 (11)
C120.0203 (13)0.0182 (14)0.0271 (14)0.0014 (10)0.0040 (11)0.0032 (11)
C130.0197 (14)0.0254 (15)0.0264 (15)0.0090 (11)0.0015 (11)0.0065 (12)
C210.0373 (17)0.0204 (15)0.0327 (16)0.0028 (12)0.0080 (13)0.0050 (12)
N10.0224 (19)0.028 (2)0.034 (2)0.0121 (16)0.0011 (15)0.0093 (16)
Geometric parameters (Å, º) top
Cl3—C31.749 (3)C4—C51.373 (4)
O11—C11.379 (3)C5—C61.383 (4)
O11—C121.419 (3)C12—C131.514 (4)
O13—C131.227 (3)C4—H40.9500
O14—C131.293 (3)C5—H50.9500
O14—H141.2500C6—H60.9500
N1—H120.93 (3)C12—H1220.9900
N1—H100.94 (4)C12—H1210.9900
N1—H110.94 (5)C21—H2120.9800
N1—H130.93 (5)C21—H2130.9800
C1—C21.404 (4)C21—H2110.9800
C1—C61.384 (4)C21—H2150.9900
C2—C211.497 (4)C21—H2161.0100
C2—C31.383 (4)C21—H2140.9800
C3—C41.386 (4)
C1—O11—C12116.2 (2)C3—C4—H4121.00
C13—O14—H14115.00C5—C4—H4121.00
H10—N1—H11110 (5)C4—C5—H5119.00
H10—N1—H12115 (5)C6—C5—H5119.00
H10—N1—H13111 (5)C5—C6—H6120.00
H12—N1—H13102 (5)C1—C6—H6120.00
H11—N1—H12120 (5)O11—C12—H121110.00
H11—N1—H1398 (5)O11—C12—H122110.00
O11—C1—C6123.7 (2)C13—C12—H121110.00
O11—C1—C2114.9 (2)C13—C12—H122110.00
C2—C1—C6121.5 (2)H121—C12—H122108.00
C1—C2—C21120.6 (2)H214—C21—H215104.00
C1—C2—C3116.3 (2)H214—C21—H216113.00
C3—C2—C21123.2 (2)H215—C21—H216107.00
Cl3—C3—C4116.8 (2)C2—C21—H211109.00
C2—C3—C4123.7 (3)C2—C21—H212109.00
Cl3—C3—C2119.5 (2)C2—C21—H213109.00
C3—C4—C5117.9 (3)C2—C21—H214110.00
C4—C5—C6121.2 (3)C2—C21—H215112.00
C1—C6—C5119.5 (3)C2—C21—H216110.00
O11—C12—C13110.4 (2)H211—C21—H212109.00
O13—C13—O14126.3 (3)H211—C21—H213109.00
O14—C13—C12111.1 (2)H212—C21—H213110.00
O13—C13—C12122.6 (2)
C12—O11—C1—C2174.3 (2)C1—C2—C3—C40.5 (4)
C12—O11—C1—C65.3 (4)C21—C2—C3—Cl31.9 (4)
C1—O11—C12—C13171.5 (2)C21—C2—C3—C4178.9 (3)
O11—C1—C2—C3179.9 (2)Cl3—C3—C4—C5178.3 (2)
O11—C1—C2—C210.7 (4)C2—C3—C4—C51.0 (4)
C6—C1—C2—C30.3 (4)C3—C4—C5—C60.7 (4)
C6—C1—C2—C21179.7 (3)C4—C5—C6—C10.1 (4)
O11—C1—C6—C5179.8 (2)O11—C12—C13—O131.3 (4)
C2—C1—C6—C50.6 (4)O11—C12—C13—O14179.3 (2)
C1—C2—C3—Cl3178.7 (2)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O14—H14···O14i1.251.252.494 (3)180
O14—H14···O13i1.252.553.326 (3)118
N1—H10···O13ii0.94 (4)2.01 (4)2.941 (2)173 (6)
N1—H11···O13iii0.94 (5)1.92 (5)2.853 (2)171 (5)
N1—H12···O110.93 (3)2.52 (4)3.3458 (19)147 (4)
N1—H13···O14iv0.93 (5)2.29 (4)3.194 (2)163 (5)
C21—H211···Cl30.982.553.075 (3)113
C21—H214···O110.982.312.746 (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

First citationChowdhury, M. & Kariuki, B. M. (2006). Cryst. Growth Des. 6, 774–780.  Web of Science CSD CrossRef CAS Google Scholar
First citationFarrugia, L. J. (2012). J. Appl. Cryst. 45, 849–854.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationLiu, 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
First citationOdendal, J. A., Bruce, J. C., Koch, K. R. & Haynes, D. A. (2010). CrystEngComm, 12, 2398–2408.  Web of Science CSD CrossRef CAS Google Scholar
First citationRigaku OD (2015). CrysAlis PRO. Rigaku Oxford Diffraction Ltd, Yarnton, Oxfordshire, England.  Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationShrivastava, H. N. & Speakman, J. C. (1961). J. Chem. Soc. A, pp. 1151–1163.  Google Scholar
First citationSmith, G. (2013). Private communication (deposition No. 965177). CCDC, Cambridge, England.  Google Scholar
First citationSmith, G. (2014). Acta Cryst. E70, 528–532.  CSD CrossRef IUCr Journals Google Scholar
First citationSmith, G. (2015). Acta Cryst. E71, o717–o718.  CrossRef IUCr Journals Google Scholar
First citationSmith, 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
First citationSmith, G. & Lynch, D. E. (2014). Acta Cryst. C70, 606–612.  Web of Science CSD CrossRef IUCr Journals Google Scholar
First citationSpek, A. L. (2009). Acta Cryst. D65, 148–155.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationZimdahl, R. L. (2010). In A History of Weed Science in the United States. New York: Elsevier.  Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.

Journal logoIUCrDATA
ISSN: 2414-3146
Follow IUCr Journals
Sign up for e-alerts
Follow IUCr on Twitter
Follow us on facebook
Sign up for RSS feeds