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ISSN: 2056-9890
Volume 71| Part 10| October 2015| Pages 1177-1180
doi:10.1107/S2056989015016722

Crystal structures of the potassium and rubidium salts of (3,5-di­chloro­phen­­oxy)acetic acid: two isotypic coordination polymers

CROSSMARK_Color_square_no_text.svg
Graham Smitha*

aScience and Engineering Faculty, Queensland University of Technology, GPO Box 2434, Brisbane, Queensland 4001, Australia
*Correspondence e-mail: g.smith@qut.edu.au

Edited by M. Weil, Vienna University of Technology, Austria (Received 18 August 2015; accepted 7 September 2015; online 17 September 2015)

The two-dimensional coordination polymeric structures of the hydrated potassium and rubidium salts of (3,5-di­chloro­phen­oxy)acetic acid (3,5-D), namely, poly[μ-aqua-bis­[μ3-2-(3,5-di­chloro­phen­oxy)acetato]­dipotassium], [K2(C8H5Cl2O3)2(H2O)]n, and poly[μ-aqua-bis­[μ3-2-(3,5-di­chloro­phen­oxy)acetato]­dirubidium], [Rb2(C8H5Cl2O3)2(H2O)]n, respectively, have been determined and are described. The two compounds are isotypic and the polymeric structure is based on centrosymmetric dinuclear bridged complex units. The irregular six-coordination about the alkali cations comprises a bridging water mol­ecule lying on a twofold rotation axis, the phen­oxy O-atom donor and a triple bridging carboxyl­ate O atom of the oxo­acetate side chain of the 3,5-D ligand, and the second carb­oxy­ate O-atom donor also bridging. The K—O and Rb—O bond-length ranges are 2.7238 (15)–2.9459 (14) and 2.832 (2)–3.050 (2) Å, respectively, and the K⋯K and Rb⋯Rb separations in the dinuclear units are 4.0214 (7) and 4.1289 (6) Å, respectively. Within the layers which lie parallel to (100), the coordinating water mol­ecule forms an O—H⋯O hydrogen bond to the single bridging carboxyl­ate O atom.

CCDC references: 1422835; 1422834

1. Chemical context

The phen­oxy­acetic acids are a particularly useful series of compounds since certain members having specific ring-substituents have herbicidal activity, resulting in their being used commercially. Of these, the most common have been the chlorine-substituted analogues (2,4-di­chloro­phen­oxy)acetic acid (2,4-D), (2,4,5-tri­chloro­phen­oxy)acetic acid (2,4,5-T) and (4-chloro-2-methyl­phen­oxy)acetic acid (MCPA) (Zumdahl, 2010[Zumdahl, R. L. (2010). In A History of Weed Science in the United States. New York: Elsevier.]). As such, the active members have received considerable attention, particularly with respect to health aspects resulting from residual breakdown components after environmental exposure. Compounds formed from their reaction with a wide range of metals have provided a significant number of crystal structures, e.g. for 2,4-D, there are 60 examples of metal complexes, contained in the Cambridge Structural Database (CSD; Groom & Allen, 2014[Groom, C. R. & Allen, F. H. (2014). Angew. Chem. Int. Ed. 53, 662-671.]), e.g. with CaII (Song et al., 2002[Song, W.-D., Huang, X.-H., Yan, J.-B. & Ma, D.-Y. (2008). Acta Cryst. E64, m654.]) and with ZnII (Kobylecka et al., 2012[Kobylecka, J., Kruszynski, R., Beniak, S. & Czubacka, E. (2012). J. Chem. Crystallogr. 42, 405-415.]).

Metal complex formation with the phen­oxy­acetic acids has been facilitated by their versatility as ligands, showing various inter­active modes with common metals including monodentate and bidentate-bridging coordinations involving the Ocarbox­yl, O1phen­oxy [(O,O)1] chelate inter­action, first reported for the monomeric copper(II) phen­oxy­acetate complex (Prout et al., 1968[Prout, C. K., Armstrong, R. A., Carruthers, J. R., Forrest, J. G., Murray-Rust, P. & Rossotti, F. J. C. (1968). J. Chem. Soc. A, pp. 2791-2813.]) and also found in the potassium–2,4-D salt (Kennard et al., 1983[Kennard, C. H. L., Smith, G. & O'Reilly, E. J. (1983). Inorg. Chim. Acta, 77, L181-L184.]) as well as in the caesium complexes with 4-fluoro­phen­oxy­acetate and (4-chloro-2-meth­yl)phen­oxy­acetate (Smith, 2015a[Smith, G. (2015a). Acta Cryst. C71, 140-145.]). In the caesium complex-adduct with 2,4-D (Smith & Lynch, 2014[Smith, G. & Lynch, D. E. (2014). Acta Cryst. C70, 606-612.]), a tridentate chelate inter­action variant is found which includes, in addition to the O,O1-chelate, a Cs—Cl bond to the ortho-Cl ring substituent of the ligand. Only occasional examples of the bidentate carboxyl­ate O,O′-chelate inter­action are found, e.g. with the previously mentioned caesium 4-fluoro­phen­oxy­acetate.

However, examples of structures of alkali metal salts of the phen­oxy­acetic acids are not common in the crystallographic literature, comprising, apart from the previously mentioned examples, the following: sodium phen­oxy­acetate hemihydrate (Prout et al., 1971[Prout, C. K., Dunn, R. M., Hodder, O. J. R. & Rossotti, F. J. C. (1971). J. Chem. Soc. A, pp. 1986-1988.]; Evans et al., 2001[Evans, J. M. B., Kapitan, A., Rosair, G. M., Roberts, K. J. & White, G. (2001). Acta Cryst. C57, 1277-1278.]), anhydrous caesium phen­oxy­acetate (Smith, 2014a[Smith, G. (2014a). Private communication (refcode WOCGAY). CCDC, Cambridge, England.]), the lithium, rubidium and caesium complexes of 2,4-D (Smith, 2015a[Smith, G. (2015a). Acta Cryst. C71, 140-145.]), caesium o-phenyl­ene­dioxydi­acetate dihydrate (Smith et al., 1989[Smith, G., O'Reilly, E. J., Kennard, C. H. L. & Mak, T. C. W. (1989). Acta Cryst. C45, 1731-1733.]) and the lithium salts of (2-chloro­phen­oxy)acetic acid (O'Reilly et al., 1987[O'Reilly, E. J., Smith, G., Kennard, C. H. L. & Mak, T. C. W. (1987). Aust. J. Chem. 40, 1147-1159.]), (2-carbamoylphen­oxy)acetic acid (Mak et al., 1986[Mak, T. C. W., Yip, W.-H., Kennard, C. H. L., Smith, G. & O'Reilly, E. J. (1986). Inorg. Chim. Acta, 111, L23-L25.]) and (2-carb­oxy­phen­oxy)acetic acid (Smith et al., 1986[Smith, G., O'Reilly, E. J. & Kennard, C. H. L. (1986). Acta Cryst. C42, 1329-1331.]).

[Scheme 1]

To investigate the nature of the coordination complex structures formed in the potassium and rubidium salts of the 2,4-D isomer, reactions of (3,5-di­chloro­phen­oxy)acetic acid (3,5-D) with K2CO3 and Rb2CO3 in aqueous ethanol were carried out, affording the isotypic polymeric title compounds [K2(C8H5Cl2O3)2(H2O)]n, (I)[link], and [Rb2(C8H5Cl2O3)2(H2O)]n, (II)[link], and the structures are reported herein.

2. Structural commentary

The hydrated complexes (I)[link] and (II)[link] are isotypic and are described conjointly. Each comprises a centrosymmetric dinuclear repeating unit (Fig. 1[link]) in which the irregular six-coordination about the K+ or Rb+ cations consists of a bidentate Ocarboxyl­ate (O13), Ophen­oxy (O11) chelate inter­action (Fig. 2[link]), three bridging carboxyl­ate (O13i, O13ii, O14iii; for symmetry codes, see Table 1[link]) inter­actions and a single bridging water mol­ecule (O1W) lying on a twofold rotation axis. The comparative M—O bond length range for the two metals (Tables 1[link] and 2[link]) is 2.7238 (15)–2.9459 (14) Å (K) and 2.832 (2)–3.050 (2) Å (Rb), for the two O-atom donors in the (O:O1)-chelate inter­action (O13 and O11, respectively).

Table 1
Selected bond lengths (Å) for (I)[link]

K1—O1W 2.7947 (15) K1—O13i 2.7855 (15)
K1—O11 2.9459 (14) K1—O13ii 2.7462 (13)
K1—O13 2.7238 (15) K1—O14iii 2.7309 (16)
Symmetry codes: (i) x, y+1, z; (ii) -x+1, -y+1, -z+1; (iii) [x, -y+1, z-{\script{1\over 2}}].

Table 2
Selected bond lengths (Å) for (II)[link]

Rb1—O1W 2.924 (2) Rb1—O13i 2.874 (2)
Rb1—O11 3.050 (2) Rb1—O13ii 2.894 (2)
Rb1—O13 2.832 (2) Rb1—O14iii 2.842 (2)
Symmetry codes: (i) x, y+1, z; (ii) -x+1, -y+1, -z+1; (iii) [x, -y+1, z-{\script{1\over 2}}].
[Figure 1]
Figure 1
A view of the partially expanded polymeric extension of the structures of (I)[link] and (II)[link], shown with 30% probability ellipsoids (with data taken from the potassium structure). [See Table 1[link] for symmetry codes; additionally: (vi) x − 1, y, z; (vii) x, y − 1, z.]
[Figure 2]
Figure 2
The mol­ecular configuration and atom-numbering scheme for the isomeric K and Rb complexes with 3,5-D [(I) and (II)], with displacement ellipsoids drawn at the 40% probability level (with data taken from the potassium structure). For symmetry codes, see Table 1[link].

Two-dimensional coordination polymeric structures are generated, lying parallel to (100) (Fig. 3[link]), in which the core sheet comprises the M—O complex network with the aromatic rings of the ligands peripherally located between the layers. Within the layers there are a number of short metal⋯metal contacts, the shortest being across an inversion centre [K⋯Kii = 4.0214 (7) Å and Rb⋯Rbii = 4.1289 (6) Å], the longest being K⋯Kvi = 4.3327 (5) Å and Rb⋯Rbvi = 4.5483 (5) Å [symmetry codes: (ii) −x + 1, −y + 1, −z + 1; (vi) −x + 1, y, −z + [{1\over 2}]]. No inter-ring π–π inter­actions are found in either (I)[link] or (II)[link], the minimum ring-centroid separations being 4.3327 (1) Å in (I)[link] and 4.3302 (3) Å in (II)[link], (the b-axis dimensions). The coordinating water mol­ecules on the twofold rotation axes are involved in intra-layer bridging O—H⋯Ocarbox­yl hydrogen-bonding inter­actions (with O14 and O14iv) (Tables 3[link] and 4[link]).

Table 3
Hydrogen-bond geometry (Å, °) for (I)[link]

D—H⋯A D—H H⋯A D⋯A D—H⋯A
O1W—H1W⋯O14iv 0.85 (2) 1.90 (2) 2.750 (2) 174 (2)
Symmetry code: (iv) -x+1, -y, -z+1.

Table 4
Hydrogen-bond geometry (Å, °) for (II)[link]

D—H⋯A D—H H⋯A D⋯A D—H⋯A
O1W—H1W⋯O14iv 0.89 (3) 1.87 (3) 2.750 (3) 171 (5)
Symmetry code: (iv) -x+1, -y, -z+1.
[Figure 3]
Figure 3
The packing of the layered structure of compounds (I)[link] and (II)[link] in the unit cell, viewed approximately along [010]. Non-associated H atoms have been omitted.

The 3,5-D anions in both (I)[link] and (II)[link] adopt the anti­periplanar conformation with the defining oxo­acetate side chain torsion angles C1—O11—C12—O13 of −171.55 (15) and −172.4 (2)° for (I)[link], (II)[link], respectively, that are similar to −172.4 (3)° in the ammonium salt (Smith, 2015b[Smith, G. (2015b). Acta Cryst. E71, o717-o718.]). These values contrast with the value in the 2:1 3,5-D adduct with 4,4′-biphenyl [−71.6 (3)°] (synclinal) (Lynch et al., 2003[Lynch, D. E., Barfield, J., Frost, J., Antrobus, R. & Simmons, J. (2003). Cryst. Eng. 6, 109-122.]).

The present isotypic potassium and rubidium salts of (3,5-di­chloro­phen­oxy)acetic acid provide an example of isotypism which extends to the ammonium salt (Smith, 2015b[Smith, G. (2015b). Acta Cryst. E71, o717-o718.]). Isotypism is also found in the analogous NH4+, K+ and Rb+ hemihydrate salts of isomeric 2,4-D (Table 5[link]). It may also be possible that a similar series exists with MCPA for which the structure of only the ammonium hemihydrate salt (NH4+ MCPA−·0.5H2O) is known (Smith, 2014b[Smith, G. (2014b). Acta Cryst. E70, 528-532.]). It is of note that the sodium salts are not included in the sets, the structures for which are not known.

Table 5
Comparative cell data (Å, °, Å3) for NH4+, K+ and Rb+ salts of (3,5-di­chloro­phen­oxy)acetic acid (3,5-D), (2,4-di­chloro­phen­oxy)acetic acid (2,4-D) and (4-chloro-2-methyl­phen­oxy)acetic acid (MCPA)

Cell parameters NH4+3,5-D−·0.5H2O K+3,5-D−·0.5H2O Rb+3,5-D−·0.5H2O NH4+2,4-D−·0.5H2O K+2,4-D−·0.5H2O Rb+2,4-D−·0.5H2O NH4+MCPA−·0.5H2O
a 39.818 (3) 39.274 (2) 39.641 (3) 39.3338 (8) 36.80 (1) 37.254 (2) 38.0396 (9)
b 4.3340 (4) 4.3327 (3) 4.3302 (3) 4.3889 (9) 4.339 (1) 4.3589 (3) 4.456 (5)
c 12.7211 (8) 12.4234 (10) 12.8607 (8) 12.900 (3) 12.975 (7) 13.238 (1) 12.944 (5)
β (°) 98.098 (5) 99.363 (6) 98.404 (5) 103.83 (3) 102.03 (4) 103.231 (7) 104.575 (5)
V 2178.4 (5) 2085.8 (3) 2183.9 (3) 2074.7 (8) 2026 (2) 2092.6 (3) 2123 (3)
Z 8 8 8 8 8 8 8
Space group C2/c C2/c C2/c C2/c C2/c C2/c C2/c
Reference Smith (2015b[Smith, G. (2015b). Acta Cryst. E71, o717-o718.]) This work (I) This work (II) Liu et al. (2009[Liu, H.-L., Guo, S.-H., Li, Y.-Y. & Jian, F.-F. (2009). Acta Cryst. E65, o1905.]) Smith (2015a[Smith, G. (2015a). Acta Cryst. C71, 140-145.]) Smith (2015a[Smith, G. (2015a). Acta Cryst. C71, 140-145.]) Smith (2014b[Smith, G. (2014b). Acta Cryst. E70, 528-532.])

3. Synthesis and crystallization

Compounds (I)[link] and (II)[link] were synthesized by the addition of 0.5 mmol of K2CO3 (65 mg) [for (I)] or Rb2CO3 (115 mg) (for (II)] to a hot solution of (3,5-di­chloro­phen­oxy)acetic acid (3,5-D) (220 mg) in 10 ml of 50% (v/v) ethanol/water. After heating for 5 min, partial room temperature evaporation of the solutions gave in all two cases, colourless needles from which specimens were cleaved for the X-ray analyses.

4. Refinement details

Crystal data, data collection and structure refinement details for (I)[link] and (II)[link] are summarized in Table 6[link]. Hydrogen atoms were placed in calculated positions [C—Haromatic = 0.95 Å or C—Hmethyl­ene = 0.99 Å] and were allowed to ride in the refinements, with Uiso(H) = 1.2Ueq(C). The water H-atom in both structures was located in a difference Fourier map and was allowed to ride in the refinements with an O—H distance restraint of 0.90±0.02 Å and with Uiso(H) = 1.5Ueq(O).

Table 6
Experimental details

  (I) (II)
Crystal data
Chemical formula [K2(C8H5Cl2O3)2(H2O)] [Rb2(C8H5Cl2O3)2(H2O)]
Mr 536.26 629.00
Crystal system, space group Monoclinic, C2/c Monoclinic, C2/c
Temperature (K) 200 200
a, b, c (Å) 39.274 (2), 4.3327 (3), 12.4234 (10) 39.641 (3), 4.3302 (3), 12.8607 (8)
β (°) 99.363 (6) 98.404 (5)
V (Å3) 2085.8 (3) 2183.9 (3)
Z 4 4
Radiation type Mo Kα Mo Kα
μ (mm−1) 1.00 5.01
Crystal size (mm) 0.45 × 0.12 × 0.04 0.40 × 0.12 × 0.04
 
Data collection
Diffractometer Oxford Diffraction Gemini-S CCD detector Oxford Diffraction Gemini-S CCD detector
Absorption correction Multi-scan (CrysAlis PRO; Agilent, 2013[Agilent (2013). CrysAlis PRO. Agilent Technologies Ltd, Yarnton, England.]) Multi-scan (CrysAlis PRO; Agilent, 2013[Agilent (2013). CrysAlis PRO. Agilent Technologies Ltd, Yarnton, England.])
Tmin, Tmax 0.774, 0.980 0.369, 0.980
No. of measured, independent and observed [I > 2σ(I)] reflections 6745, 2061, 1824 7520, 2152, 1910
Rint 0.035 0.055
(sin θ/λ)max (Å−1) 0.617 0.617
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.031, 0.076, 1.07 0.040, 0.095, 1.06
No. of reflections 2061 2152
No. of parameters 135 136
No. of restraints 1 1
H-atom treatment H atoms treated by a mixture of independent and constrained refinement H atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3) 0.27, −0.25 0.98, −1.00
Computer programs: CrysAlis PRO (Agilent, 2013[Agilent (2013). CrysAlis PRO. Agilent Technologies Ltd, Yarnton, England.]), SIR92 (Altomare et al., 1993[Altomare, A., Cascarano, G., Giacovazzo, C. & Guagliardi, A. (1993). J. Appl. Cryst. 26, 343-350.]), SHELXS97 and 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.]), PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]).

Supporting information

CCDC references: 1422835; 1422834

Crystal structure: contains datablocks global, I, II. DOI: 10.1107/S2056989015016722/wm5206sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S2056989015016722/wm5206Isup2.hkl

Structure factors: contains datablock II. DOI: 10.1107/S2056989015016722/wm5206IIsup3.hkl

Supporting information file. DOI: 10.1107/S2056989015016722/wm5206Isup4.cml

Supporting information file. DOI: 10.1107/S2056989015016722/wm5206IIsup5.cml

checkCIF report


Chemical context top

The phen­oxy­acetic acids are a particularly useful series of compounds since certain members having specific ring-substituents have herbicidal activity, resulting in their being used commercially. Of these, the most common have been the chlorine-substituted analogues (2,4-di­chloro­phen­oxy)­acetic acid (2,4-D), (2,4,5-tri­chloro­phen­oxy)­acetic acid (2,4,5-T) and (4-chloro-2-methyl­phen­oxy)­acetic acid (MCPA) (Zumdahl, 2010). As such, the active members have received considerable attention, particularly with respect to health aspects resulting from residual breakdown components after environmental exposure. Compounds formed from their reaction with a wide range of metals have provided a significant number of crystal structures, e.g. for 2,4-D, there are 60 examples of metal complexes, contained in the Cambridge Structural Database (CSD; Groom & Allen, 2014), e.g. with CaII (Song et al., 2002) and with ZnII (Kobylecka et al., 2012).

Metal complex formation with the phen­oxy­acetic acids has been facilitated by their versatility as ligands, showing various inter­active modes with common metals including monodentate and bidentate-bridging coordinations involving the Ocarboxyl, O1phen­oxy [(O,O)1] chelate inter­action, first reported for the monomeric copper(II) phen­oxy­acetate complex (Prout et al., 1968) and also found in the potassium–2,4-D salt (Kennard et al., 1983) as well as in the caesium complexes with 4-fluoro­phen­oxy­acetate and (4-chloro-2-methyl)­phen­oxy­acetate (Smith, 2015a). In the caesium complex-adduct with 2,4-D (Smith & Lynch, 2014), a tridentate chelate inter­action variant is found which includes, in addition to the O,O1-chelate, a Cs—Cl bond to the ortho-Cl ring substituent of the ligand. Only occasional examples of the bidentate carboxyl­ate O,O'-chelate inter­action are found, e.g. with the previously mentioned caesium 4-fluoro­phen­oxy­acetate.

However, examples of structures of alkali metal salts of the phen­oxy­acetic acids are not common in the crystallographic literature, comprising, apart from the previously mentioned examples, the following: sodium phen­oxy­acetate hemihydrate (Prout et al., 1971; Evans et al., 2001), anhydrous caesium phen­oxy­acetate (Smith, 2014a), the lithium, rubidium and caesium complexes of 2,4-D (Smith, 2015a), caesium o-phenyl­ene­dioxydi­acetate dihydrate (Smith et al., 1989) and the lithium salts of (2-chloro­phen­oxy)­acetic acid (O'Reilly et al., 1987), (2-carbamoyl­phen­oxy)­acetic acid (Mak et al., 1986) and (2-carb­oxy­phen­oxy)­acetic acid (Smith et al., 1986).

To investigate the nature of the coordination complex structures formed in the potassium and rubidium salts of the 2,4-D isomer, reactions of (3,5-di­chloro­phen­oxy)­acetic acid (3,5-D) with K2CO3 and Rb2CO3 in aqueous ethanol was carried out, affording the isotypic polymeric title compounds [K2(C8H5Cl2O3)2(H2O)]n, (I), and [Rb2(C8H5Cl2O3)2(H2O)]n, (II), and the structures are reported herein.

Structural commentary top

The hydrated complexes (I) and (II) are isotypic and are described conjointly. Each comprises a centrosymmetric dinuclear repeating unit (Fig. 1) in which the irregular six-coordination about the K+ or Rb+ cations comprises a bidentate Ocarboxyl­ate (O13), Ophen­oxy (O11) chelate inter­action (Fig. 2), three bridging carboxyl­ate (O13i, O13ii, O14iii; for symmetry codes, see Table 1) inter­actions and a single bridging water molecule (O1W) lying on a twofold rotation axis. The comparative M—O bond length range for the two metals (Tables 1 and 2) is 2.7238 (15)–2.9459 (14) Å (K) and 2.832 (2)–3.050 (2) Å (Rb), for the two O-atom donors in the (O:O1)-chelate inter­action (O13 and O11, respectively).

Two-dimensional coordination polymeric structures are generated, lying parallel to (100) (Fig. 3), in which the core sheet comprises the M—O complex network with the aromatic rings of the ligands peripherally located between the layers. Within the layers there are a number of short metal···metal contacts, the shortest being across an inversion centre [K···Kii = 4.0214 (7) Å and Rb···Rbii = 4.1289 (6) Å], the longest being K···Kvi = 4.3327 (5) Å and Rb···Rbvi = 4.5483 (5) Å [symmetry codes: (ii) -x + 1, -y + 1, -z + 1; (vi) -x + 1, y, -z + 1/2]. No inter-ring π–π inter­actions are found in either (I) or (II), the minimum ring-centroid separations being 4.3327 (1) Å in (I) and 4.3302 (3) Å in (II), (the b-axis dimensions). The coordinating water molecules on the twofold rotation axes are involved in intra-layer bridging O—H···Ocarboxyl hydrogen-bonding inter­actions (with O14 and O14iv) (Tables 3 and 4).

The 3,5-D anions in both (I) and (II) adopt the anti­periplanar conformation with the defining oxo­acetate side chain torsion angles C1—O11—C12—O13 of -171.55 (15) and -172.4 (2)° for (I), (II), respectively, that are similar to -172.4 (3)° in the ammonium salt (Smith, 2015b). These values contrast with the value in the 2:1 3,5-D adduct with 4,4'-bi­phenyl [-71.6 (3)°] (synclinal) (Lynch et al., 2003).

The present isotypic potassium and rubidium salts of (3,5-di­chloro­phen­oxy)­acetic acid provide an example of isotypism which extends to the ammonium salt (Smith, 2015b). Isotypism is also found in the analogous NH4+, K+ and Rb+ hemihydrate salts of isomeric 2,4-D (Table 5). It may also be possible that a similar series exists with MCPA for which the structure of only the ammonium hemihydrate salt (NH4+ MCPA-·0.5H2O) is known (Smith, 2014b). It is of note that the sodium salts are not included in the sets, the structures for which are not known.

Synthesis and crystallization top

Compounds (I) and (II) were synthesized by the addition of 0.5 mmol of K2CO3 (65 mg) [for (I)] or Rb2CO3 (115 mg) (for (II)] to a hot solution of (3,5-di­chloro­phen­oxy)­acetic acid (3,5-D) (220 mg) in 10 ml of 50% (v/v) ethanol/water. After heating for 5 min, partial room temperature evaporation of the solutions gave in all two cases, colourless needles from which specimens were cleaved for the X-ray analyses.

Refinement details top

Crystal data, data collection and structure refinement details for (I) and (II) are summarized in Table 6. Hydrogen atoms were placed in calculated positions [C—Haromatic = 0.95 Å or C—Hmethyl­ene = 0.99 Å] and were allowed to ride in the refinements, with Uiso(H) = 1.2Ueq(C). The water H-atom in both structures was located in a difference Fourier map and was allowed to ride in the refinements with an O—H distance restraint of 0.90±0.02 Å and with Uiso(H) = 1.5Ueq(O).

Related literature top

For related literature, see: Evans et al. (2001); Kennard et al. (1983); Kobylecka et al. (2012); Lynch et al. (2003); Mak et al. (1986); O'Reilly et al. (1987); Prout et al. (1968, 1971); Smith (2014a, 2014b, 2015a, 2015b); Smith & Lynch (2014); Smith et al. (1986, 1989); Song et al. (2002); Zumdahl (2010).

Computing details top

For both compounds, data collection: CrysAlis PRO (Agilent, 2013); cell refinement: CrysAlis PRO (Agilent, 2013); data reduction: CrysAlis PRO (Agilent, 2013). Program(s) used to solve structure: SIR92 (Altomare et al., 1993) for (I); SHELXS97 (Sheldrick, 2008) for (II). For both compounds, 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).

Figures top
[Figure 1] Fig. 1. A view of the partially expanded polymeric extension of the structures of (I) and (II), shown with 30% probability ellipsoids (with data taken from the potassium structure). [See Table 1 for symmetry codes; additionally: (vi) x - 1, y, z; (vii) x, y - 1, z.]
[Figure 2] Fig. 2. The molecular configuration and atom-numbering scheme for the isomeric K and Rb complexes with 3,5-D [(I) and (II)], with displacement ellipsoids drawn at the 40% probability level (with data taken from the potassium structure). For symmetry codes, see Table 1.
[Figure 3] Fig. 3. The packing of the layered structure of compounds (I) and (II) in the unit cell, viewed approximately along [010]. Non-associated H atoms have been omitted.
(I) Poly[µ-aqua-bis[µ3-2-(3,5-dichlorophenoxy)acetato]dipotassium] top
Crystal data top
[K2(C8H5Cl2O3)2(H2O)]F(000) = 1080
Mr = 536.26Dx = 1.708 Mg m−3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2ycCell parameters from 2400 reflections
a = 39.274 (2) Åθ = 4.2–28.6°
b = 4.3327 (3) ŵ = 1.00 mm−1
c = 12.4234 (10) ÅT = 200 K
β = 99.363 (6)°Flat prism, colourless
V = 2085.8 (3) Å30.45 × 0.12 × 0.04 mm
Z = 4
Data collection top
Oxford Diffraction Gemini-S CCD-detector
diffractometer		2061 independent reflections
Radiation source: Enhance (Mo) X-ray source1824 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.035
Detector resolution: 16.077 pixels mm-1θmax = 26.0°, θmin = 3.2°
ω scansh = −48→47
Absorption correction: multi-scan
(CrysAlis PRO; Agilent, 2013)		k = −5→5
Tmin = 0.774, Tmax = 0.980l = −15→15
6745 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)] = 0.031Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.076H atoms treated by a mixture of independent and constrained refinement
S = 1.07 w = 1/[σ2(Fo2) + (0.0337P)2 + 0.706P]
where P = (Fo2 + 2Fc2)/3
2061 reflections(Δ/σ)max = 0.001
135 parametersΔρmax = 0.27 e Å−3
1 restraintΔρmin = −0.25 e Å−3
Crystal data top
[K2(C8H5Cl2O3)2(H2O)]V = 2085.8 (3) Å3
Mr = 536.26Z = 4
Monoclinic, C2/cMo Kα radiation
a = 39.274 (2) ŵ = 1.00 mm−1
b = 4.3327 (3) ÅT = 200 K
c = 12.4234 (10) Å0.45 × 0.12 × 0.04 mm
β = 99.363 (6)°
Data collection top
Oxford Diffraction Gemini-S CCD-detector
diffractometer		2061 independent reflections
Absorption correction: multi-scan
(CrysAlis PRO; Agilent, 2013)		1824 reflections with I > 2σ(I)
Tmin = 0.774, Tmax = 0.980Rint = 0.035
6745 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0311 restraint
wR(F2) = 0.076H atoms treated by a mixture of independent and constrained refinement
S = 1.07Δρmax = 0.27 e Å−3
2061 reflectionsΔρmin = −0.25 e Å−3
135 parameters
Special details top

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell esds are taken into account in the estimation of distances, angles and torsion angles

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 > 2sigma(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 (Å2) top
xyzUiso*/Ueq
K10.53071 (1)0.71864 (10)0.40994 (4)0.0253 (1)
Cl30.66484 (1)1.12106 (12)0.30636 (5)0.0351 (2)
Cl50.72749 (1)0.44252 (15)0.64380 (5)0.0436 (2)
O1W0.500000.3066 (5)0.250000.0301 (7)
O110.59608 (3)0.5041 (3)0.53873 (12)0.0279 (4)
O130.53561 (3)0.2277 (3)0.54855 (12)0.0279 (4)
O140.55253 (4)0.0910 (3)0.72297 (12)0.0317 (5)
C10.62867 (5)0.5876 (4)0.52303 (17)0.0226 (6)
C20.63030 (5)0.7874 (4)0.43626 (17)0.0243 (6)
C30.66234 (5)0.8758 (4)0.41548 (17)0.0250 (6)
C40.69289 (5)0.7753 (5)0.47741 (18)0.0286 (6)
C50.69014 (5)0.5791 (5)0.56273 (18)0.0268 (6)
C60.65879 (5)0.4817 (5)0.58735 (17)0.0242 (6)
C120.59359 (5)0.3273 (5)0.63485 (17)0.0276 (6)
C130.55716 (5)0.2100 (4)0.63421 (17)0.0228 (6)
H1W0.4837 (5)0.189 (5)0.263 (2)0.0340*
H20.609800.861100.392400.0290*
H40.714700.838800.461700.0340*
H60.657800.345700.646700.0290*
H1210.600600.457500.700200.0330*
H1220.609600.149800.639200.0330*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
K10.0223 (2)0.0305 (2)0.0223 (3)−0.0004 (2)0.0016 (2)−0.0001 (2)
Cl30.0440 (3)0.0342 (3)0.0282 (3)−0.0098 (2)0.0095 (3)0.0029 (2)
Cl50.0188 (3)0.0630 (4)0.0457 (4)−0.0017 (3)−0.0046 (2)0.0085 (3)
O1W0.0230 (11)0.0293 (11)0.0381 (14)0.00000.0051 (10)0.0000
O110.0163 (7)0.0415 (8)0.0251 (8)−0.0026 (6)0.0011 (6)0.0101 (7)
O130.0197 (7)0.0353 (8)0.0266 (8)−0.0036 (6)−0.0028 (6)−0.0003 (7)
O140.0293 (8)0.0418 (9)0.0251 (9)−0.0062 (7)0.0075 (7)0.0028 (7)
C10.0185 (10)0.0278 (10)0.0214 (11)−0.0023 (8)0.0029 (8)−0.0037 (9)
C20.0228 (10)0.0267 (10)0.0226 (11)−0.0002 (8)0.0015 (8)−0.0016 (9)
C30.0302 (11)0.0243 (10)0.0211 (11)−0.0049 (9)0.0061 (9)−0.0034 (9)
C40.0222 (10)0.0348 (11)0.0297 (12)−0.0077 (9)0.0070 (9)−0.0070 (10)
C50.0180 (10)0.0338 (11)0.0266 (12)−0.0019 (8)−0.0023 (8)−0.0039 (9)
C60.0206 (10)0.0303 (10)0.0213 (11)−0.0027 (8)0.0021 (8)−0.0005 (9)
C120.0232 (11)0.0384 (11)0.0200 (11)−0.0054 (9)0.0002 (9)0.0063 (9)
C130.0196 (10)0.0233 (9)0.0256 (12)0.0003 (8)0.0039 (9)−0.0039 (9)
Geometric parameters (Å, º) top
K1—O1W2.7947 (15)O1W—H1Wiv0.85 (2)
K1—O112.9459 (14)C1—C61.393 (3)
K1—O132.7238 (15)C1—C21.392 (3)
K1—O13i2.7855 (15)C2—C31.379 (3)
K1—O13ii2.7462 (13)C3—C41.386 (3)
K1—O14iii2.7309 (16)C4—C51.377 (3)
Cl3—C31.738 (2)C5—C61.382 (3)
Cl5—C51.742 (2)C12—C131.517 (3)
O11—C11.374 (2)C2—H20.9500
O11—C121.435 (3)C4—H40.9500
O13—C131.250 (2)C6—H60.9500
O14—C131.257 (2)C12—H1210.9900
O1W—H1W0.85 (2)C12—H1220.9900
O1W—K1—O11114.95 (4)H1W—O1W—H1Wiv107 (2)
O1W—K1—O1385.90 (5)K1iv—O1W—H1Wiv119.8 (16)
O1W—K1—O13i157.48 (4)O11—C1—C2115.78 (17)
O1W—K1—O13ii82.81 (3)O11—C1—C6123.74 (18)
O1W—K1—O14iii75.35 (4)C2—C1—C6120.48 (18)
O11—K1—O1356.26 (4)C1—C2—C3118.42 (18)
O11—K1—O13i87.00 (4)C2—C3—C4122.86 (19)
O11—K1—O13ii133.96 (4)Cl3—C3—C4118.13 (15)
O11—K1—O14iii101.01 (4)Cl3—C3—C2119.01 (15)
O13—K1—O13i103.70 (4)C3—C4—C5116.88 (18)
O13—K1—O13ii85.35 (4)Cl5—C5—C4119.39 (16)
O13—K1—O14iii140.71 (4)C4—C5—C6122.91 (19)
O13i—K1—O13ii77.83 (4)Cl5—C5—C6117.71 (17)
O13i—K1—O14iii106.68 (4)C1—C6—C5118.45 (19)
O13ii—K1—O14iii124.93 (5)O11—C12—C13111.48 (16)
K1—O1W—K1iv100.60 (7)O13—C13—C12119.43 (18)
K1—O11—C1126.11 (11)O14—C13—C12113.81 (18)
K1—O11—C12116.68 (10)O13—C13—O14126.70 (18)
C1—O11—C12116.72 (15)C1—C2—H2121.00
K1—O13—C13123.69 (11)C3—C2—H2121.00
K1—O13—K1v103.70 (5)C3—C4—H4122.00
K1—O13—K1ii94.65 (4)C5—C4—H4122.00
K1v—O13—C13116.55 (11)C1—C6—H6121.00
K1ii—O13—C13112.14 (12)C5—C6—H6121.00
K1v—O13—K1ii102.18 (4)O11—C12—H121109.00
K1vi—O14—C13137.09 (12)O11—C12—H122109.00
K1iv—O1W—H1W105.4 (15)C13—C12—H121109.00
K1—O1W—H1W119.8 (16)C13—C12—H122109.00
K1—O1W—H1Wiv105.4 (15)H121—C12—H122108.00
O11—K1—O1W—K1iv−146.99 (3)O13—K1—O13ii—K1ii−0.02 (5)
O13—K1—O1W—K1iv163.37 (3)O13—K1—O13ii—C13ii−129.34 (12)
O1W—K1—O11—C199.66 (13)O11—K1—O14iii—C13iii87.4 (2)
O1W—K1—O11—C12−88.68 (13)O13—K1—O14iii—C13iii38.4 (2)
O13—K1—O11—C1165.74 (15)K1—O11—C1—C2−1.4 (2)
O13—K1—O11—C12−22.60 (12)K1—O11—C1—C6179.21 (14)
O13i—K1—O11—C1−85.59 (14)C12—O11—C1—C2−173.08 (17)
O13i—K1—O11—C1286.08 (12)C12—O11—C1—C67.6 (3)
O13ii—K1—O11—C1−155.47 (13)K1—O11—C12—C1315.98 (19)
O13ii—K1—O11—C1216.20 (14)C1—O11—C12—C13−171.55 (15)
O14iii—K1—O11—C120.83 (14)K1—O13—C13—O14143.75 (15)
O14iii—K1—O11—C12−167.51 (12)K1—O13—C13—C12−39.2 (2)
O1W—K1—O13—C13156.32 (14)K1v—O13—C13—O14−85.6 (2)
O1W—K1—O13—K1v20.65 (4)K1v—O13—C13—C1291.41 (17)
O1W—K1—O13—K1ii−83.10 (4)K1ii—O13—C13—O1431.6 (2)
O11—K1—O13—C1332.52 (14)K1ii—O13—C13—C12−151.35 (14)
O11—K1—O13—K1v−103.16 (5)K1vi—O14—C13—O13−90.6 (2)
O11—K1—O13—K1ii153.10 (6)K1vi—O14—C13—C1292.3 (2)
O13i—K1—O13—C13−44.32 (15)O11—C1—C2—C3−179.06 (16)
O13i—K1—O13—K1v179.98 (9)C6—C1—C2—C30.3 (3)
O13i—K1—O13—K1ii76.26 (5)O11—C1—C6—C5179.20 (18)
O13ii—K1—O13—C13−120.58 (14)C2—C1—C6—C5−0.1 (3)
O13ii—K1—O13—K1v103.75 (5)C1—C2—C3—Cl3179.16 (14)
O13ii—K1—O13—K1ii0.02 (8)C1—C2—C3—C4−0.3 (3)
O14iii—K1—O13—C1395.53 (16)Cl3—C3—C4—C5−179.45 (16)
O14iii—K1—O13—K1v−40.15 (8)C2—C3—C4—C50.0 (3)
O14iii—K1—O13—K1ii−143.89 (6)C3—C4—C5—Cl5179.79 (16)
O11—K1—O13i—K1i125.82 (4)C3—C4—C5—C60.2 (3)
O11—K1—O13i—C13i−13.64 (13)Cl5—C5—C6—C1−179.71 (16)
O13—K1—O13i—K1i180.00 (4)C4—C5—C6—C1−0.2 (3)
O13—K1—O13i—C13i40.53 (13)O11—C12—C13—O1312.0 (2)
O11—K1—O13ii—K1ii−31.51 (7)O11—C12—C13—O14−170.65 (16)
O11—K1—O13ii—C13ii−160.85 (11)
Symmetry codes: (i) x, y+1, z; (ii) −x+1, −y+1, −z+1; (iii) x, −y+1, z−1/2; (iv) −x+1, y, −z+1/2; (v) x, y−1, z; (vi) x, −y+1, z+1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1W—H1W···O14vii0.85 (2)1.90 (2)2.750 (2)174 (2)
Symmetry code: (vii) −x+1, −y, −z+1.
(II) Poly[µ-aqua-bis[µ3-(3,5-dichlorophenoxy)acetato]dirubidium] top
Crystal data top
[Rb2(C8H5Cl2O3)2(H2O)]F(000) = 1224
Mr = 629.00Dx = 1.913 Mg m−3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2ycCell parameters from 2435 reflections
a = 39.641 (3) Åθ = 3.6–28.3°
b = 4.3302 (3) ŵ = 5.01 mm−1
c = 12.8607 (8) ÅT = 200 K
β = 98.404 (5)°Prism, colourless
V = 2183.9 (3) Å30.40 × 0.12 × 0.04 mm
Z = 4
Data collection top
Oxford Diffraction Gemini-S CCD-detector
diffractometer		2152 independent reflections
Radiation source: Enhance (Mo) X-ray source1910 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.055
Detector resolution: 16.077 pixels mm-1θmax = 26.0°, θmin = 3.2°
ω–scansh = −45→48
Absorption correction: multi-scan
(CrysAlis PRO; Agilent, 2013)		k = −5→5
Tmin = 0.369, Tmax = 0.980l = −15→15
7520 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)] = 0.040Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.095H atoms treated by a mixture of independent and constrained refinement
S = 1.06 w = 1/[σ2(Fo2) + (0.0491P)2]
where P = (Fo2 + 2Fc2)/3
2152 reflections(Δ/σ)max = 0.003
136 parametersΔρmax = 0.98 e Å−3
1 restraintΔρmin = −1.00 e Å−3
Crystal data top
[Rb2(C8H5Cl2O3)2(H2O)]V = 2183.9 (3) Å3
Mr = 629.00Z = 4
Monoclinic, C2/cMo Kα radiation
a = 39.641 (3) ŵ = 5.01 mm−1
b = 4.3302 (3) ÅT = 200 K
c = 12.8607 (8) Å0.40 × 0.12 × 0.04 mm
β = 98.404 (5)°
Data collection top
Oxford Diffraction Gemini-S CCD-detector
diffractometer		2152 independent reflections
Absorption correction: multi-scan
(CrysAlis PRO; Agilent, 2013)		1910 reflections with I > 2σ(I)
Tmin = 0.369, Tmax = 0.980Rint = 0.055
7520 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0401 restraint
wR(F2) = 0.095H atoms treated by a mixture of independent and constrained refinement
S = 1.06Δρmax = 0.98 e Å−3
2152 reflectionsΔρmin = −1.00 e Å−3
136 parameters
Special details top

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell esds are taken into account in the estimation of distances, angles and torsion angles

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 > 2sigma(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 (Å2) top
xyzUiso*/Ueq
Rb10.53252 (1)0.71425 (8)0.41106 (2)0.0271 (1)
Cl30.66575 (3)1.1071 (2)0.31320 (7)0.0394 (3)
Cl50.72802 (2)0.4700 (3)0.64713 (9)0.0510 (4)
O1W0.500000.2897 (8)0.250000.0336 (12)
O110.59805 (6)0.4938 (6)0.54449 (18)0.0312 (8)
O130.53789 (6)0.2205 (5)0.5570 (2)0.0295 (8)
O140.55505 (6)0.0734 (6)0.72371 (19)0.0341 (8)
C10.63017 (8)0.5832 (8)0.5286 (3)0.0255 (11)
C20.63168 (10)0.7780 (8)0.4420 (3)0.0278 (11)
C30.66324 (10)0.8701 (8)0.4215 (3)0.0284 (11)
C40.69371 (11)0.7828 (8)0.4829 (3)0.0327 (12)
C50.69102 (9)0.5914 (9)0.5678 (3)0.0302 (11)
C60.66010 (8)0.4923 (8)0.5924 (3)0.0267 (11)
C120.59553 (9)0.3198 (8)0.6376 (3)0.0285 (11)
C130.55928 (9)0.1991 (8)0.6381 (3)0.0243 (11)
H1W0.4832 (8)0.172 (8)0.266 (4)0.0510*
H20.611500.844100.398800.0330*
H40.715200.850900.467300.0390*
H60.659200.364200.651900.0320*
H1210.602100.452200.700000.0340*
H1220.611600.143400.642000.0340*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Rb10.0270 (2)0.0340 (2)0.0204 (2)0.0005 (1)0.0035 (2)0.0014 (1)
Cl30.0502 (6)0.0428 (6)0.0275 (5)−0.0119 (5)0.0132 (5)0.0037 (4)
Cl50.0231 (5)0.0802 (8)0.0474 (6)−0.0029 (5)−0.0022 (5)0.0124 (6)
O1W0.028 (2)0.034 (2)0.039 (2)0.00000.0057 (19)0.0000
O110.0205 (13)0.0506 (16)0.0227 (13)−0.0044 (11)0.0038 (11)0.0129 (12)
O130.0245 (14)0.0378 (14)0.0255 (14)−0.0029 (10)0.0013 (12)−0.0011 (11)
O140.0317 (14)0.0491 (16)0.0232 (13)−0.0085 (13)0.0100 (12)0.0059 (12)
C10.0249 (19)0.0317 (19)0.0205 (18)−0.0028 (16)0.0051 (16)−0.0045 (16)
C20.027 (2)0.035 (2)0.0215 (19)−0.0002 (15)0.0038 (17)−0.0013 (15)
C30.037 (2)0.0300 (19)0.0194 (18)−0.0075 (17)0.0084 (17)−0.0052 (15)
C40.028 (2)0.044 (2)0.028 (2)−0.0104 (17)0.0106 (18)−0.0055 (17)
C50.0238 (19)0.042 (2)0.0241 (18)−0.0042 (17)0.0013 (16)−0.0036 (17)
C60.0244 (19)0.035 (2)0.0207 (18)−0.0020 (15)0.0036 (15)−0.0013 (16)
C120.025 (2)0.040 (2)0.0200 (18)−0.0040 (16)0.0018 (16)0.0041 (16)
C130.024 (2)0.0269 (18)0.0231 (19)0.0007 (15)0.0071 (17)−0.0048 (15)
Geometric parameters (Å, º) top
Rb1—O1W2.924 (2)O1W—H1Wiv0.89 (3)
Rb1—O113.050 (2)C1—C61.397 (5)
Rb1—O132.832 (2)C1—C21.405 (5)
Rb1—O13i2.874 (2)C2—C31.375 (6)
Rb1—O13ii2.894 (2)C3—C41.395 (6)
Rb1—O14iii2.842 (2)C4—C51.387 (5)
Cl3—C31.745 (4)C5—C61.378 (5)
Cl5—C51.741 (4)C12—C131.530 (5)
O11—C11.374 (4)C2—H20.9500
O11—C121.431 (4)C4—H40.9500
O13—C131.248 (5)C6—H60.9500
O14—C131.261 (4)C12—H1210.9900
O1W—H1W0.89 (3)C12—H1220.9900
O1W—Rb1—O11116.93 (7)H1W—O1W—H1Wiv110 (3)
O1W—Rb1—O1388.71 (7)Rb1iv—O1W—H1Wiv118 (3)
O1W—Rb1—O13i157.69 (6)O11—C1—C2115.8 (3)
O1W—Rb1—O13ii80.06 (5)O11—C1—C6124.0 (3)
O1W—Rb1—O14iii76.32 (6)C2—C1—C6120.3 (3)
O11—Rb1—O1354.24 (7)C1—C2—C3118.1 (3)
O11—Rb1—O13i84.01 (7)C2—C3—C4123.3 (4)
O11—Rb1—O13ii135.28 (7)Cl3—C3—C4117.8 (3)
O11—Rb1—O14iii103.36 (7)Cl3—C3—C2118.9 (3)
O13—Rb1—O13i98.73 (7)C3—C4—C5116.6 (4)
O13—Rb1—O13ii87.72 (7)Cl5—C5—C4119.1 (3)
O13—Rb1—O14iii143.47 (7)C4—C5—C6122.7 (4)
O13i—Rb1—O13ii79.26 (7)Cl5—C5—C6118.2 (3)
O13i—Rb1—O14iii107.73 (7)C1—C6—C5119.0 (3)
O13ii—Rb1—O14iii121.19 (7)O11—C12—C13111.3 (3)
Rb1—O1W—Rb1iv102.10 (11)O13—C13—C12119.7 (3)
Rb1—O11—C1124.0 (2)O14—C13—C12113.3 (3)
Rb1—O11—C12118.55 (19)O13—C13—O14126.9 (3)
C1—O11—C12116.9 (3)C1—C2—H2121.00
Rb1—O13—C13125.9 (2)C3—C2—H2121.00
Rb1—O13—Rb1v98.73 (8)C3—C4—H4122.00
Rb1—O13—Rb1ii92.28 (7)C5—C4—H4122.00
Rb1v—O13—C13117.8 (2)C1—C6—H6121.00
Rb1ii—O13—C13116.1 (2)C5—C6—H6120.00
Rb1v—O13—Rb1ii100.74 (7)O11—C12—H121109.00
Rb1vi—O14—C13134.3 (2)O11—C12—H122109.00
Rb1iv—O1W—H1W105 (3)C13—C12—H121109.00
Rb1—O1W—H1W118 (3)C13—C12—H122109.00
Rb1—O1W—H1Wiv105 (3)H121—C12—H122108.00
O11—Rb1—O1W—Rb1iv−149.55 (5)O13—Rb1—O13ii—Rb1ii0.00 (7)
O13—Rb1—O1W—Rb1iv162.30 (5)O13—Rb1—O13ii—C13ii−132.3 (2)
O1W—Rb1—O11—C1101.0 (2)O11—Rb1—O14iii—C13iii88.7 (3)
O1W—Rb1—O11—C12−87.7 (2)O13—Rb1—O14iii—C13iii42.2 (4)
O13—Rb1—O11—C1167.6 (3)Rb1—O11—C1—C2−2.7 (4)
O13—Rb1—O11—C12−21.0 (2)Rb1—O11—C1—C6177.2 (3)
O13i—Rb1—O11—C1−87.1 (2)C12—O11—C1—C2−174.3 (3)
O13i—Rb1—O11—C1284.3 (2)C12—O11—C1—C65.7 (5)
O13ii—Rb1—O11—C1−155.3 (2)Rb1—O11—C12—C1315.6 (3)
O13ii—Rb1—O11—C1216.1 (3)C1—O11—C12—C13−172.4 (3)
O14iii—Rb1—O11—C119.7 (3)Rb1—O13—C13—O14147.4 (3)
O14iii—Rb1—O11—C12−168.9 (2)Rb1—O13—C13—C12−35.8 (4)
O1W—Rb1—O13—C13155.0 (3)Rb1v—O13—C13—O14−86.3 (4)
O1W—Rb1—O13—Rb1v21.13 (6)Rb1v—O13—C13—C1290.5 (3)
O1W—Rb1—O13—Rb1ii−80.10 (5)Rb1ii—O13—C13—O1433.2 (4)
O11—Rb1—O13—C1329.9 (3)Rb1ii—O13—C13—C12−150.0 (2)
O11—Rb1—O13—Rb1v−103.93 (9)Rb1vi—O14—C13—O13−90.5 (4)
O11—Rb1—O13—Rb1ii154.83 (10)Rb1vi—O14—C13—C1292.5 (3)
O13i—Rb1—O13—C13−46.2 (3)O11—C1—C2—C3−178.9 (3)
O13i—Rb1—O13—Rb1v179.98 (11)C6—C1—C2—C31.1 (5)
O13i—Rb1—O13—Rb1ii78.77 (7)O11—C1—C6—C5178.8 (3)
O13ii—Rb1—O13—C13−124.9 (3)C2—C1—C6—C5−1.3 (5)
O13ii—Rb1—O13—Rb1v101.23 (7)C1—C2—C3—Cl3179.0 (3)
O13ii—Rb1—O13—Rb1ii0.00 (7)C1—C2—C3—C4−0.7 (6)
O14iii—Rb1—O13—C1390.3 (3)Cl3—C3—C4—C5−179.3 (3)
O14iii—Rb1—O13—Rb1v−43.54 (14)C2—C3—C4—C50.5 (5)
O14iii—Rb1—O13—Rb1ii−144.77 (9)C3—C4—C5—Cl5179.4 (3)
O11—Rb1—O13i—Rb1i127.64 (8)C3—C4—C5—C6−0.7 (6)
O11—Rb1—O13i—C13i−11.0 (2)Cl5—C5—C6—C1−178.9 (3)
O13—Rb1—O13i—Rb1i179.98 (10)C4—C5—C6—C11.1 (6)
O13—Rb1—O13i—C13i41.3 (2)O11—C12—C13—O1310.0 (4)
O11—Rb1—O13ii—Rb1ii−29.37 (12)O11—C12—C13—O14−172.7 (3)
O11—Rb1—O13ii—C13ii−161.6 (2)
Symmetry codes: (i) x, y+1, z; (ii) −x+1, −y+1, −z+1; (iii) x, −y+1, z−1/2; (iv) −x+1, y, −z+1/2; (v) x, y−1, z; (vi) x, −y+1, z+1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1W—H1W···O14vii0.89 (3)1.87 (3)2.750 (3)171 (5)
Symmetry code: (vii) −x+1, −y, −z+1.
Selected bond lengths (Å) for (I) top
K1—O1W2.7947 (15)K1—O13i2.7855 (15)
K1—O112.9459 (14)K1—O13ii2.7462 (13)
K1—O132.7238 (15)K1—O14iii2.7309 (16)
Symmetry codes: (i) x, y+1, z; (ii) −x+1, −y+1, −z+1; (iii) x, −y+1, z−1/2.
Selected bond lengths (Å) for (II) top
Rb1—O1W2.924 (2)Rb1—O13i2.874 (2)
Rb1—O113.050 (2)Rb1—O13ii2.894 (2)
Rb1—O132.832 (2)Rb1—O14iii2.842 (2)
Symmetry codes: (i) x, y+1, z; (ii) −x+1, −y+1, −z+1; (iii) x, −y+1, z−1/2.
Hydrogen-bond geometry (Å, º) for (I) top
D—H···AD—HH···AD···AD—H···A
O1W—H1W···O14iv0.85 (2)1.90 (2)2.750 (2)174 (2)
Symmetry code: (iv) −x+1, −y, −z+1.
Hydrogen-bond geometry (Å, º) for (II) top
D—H···AD—HH···AD···AD—H···A
O1W—H1W···O14iv0.89 (3)1.87 (3)2.750 (3)171 (5)
Symmetry code: (iv) −x+1, −y, −z+1.
Comparative cell data (Å, °, Å3) for NH4+, K+ and Rb+ salts of (3,5-dichlorophenoxy)acetic acid (3,5-D), (2,4-dichlorophenoxy)acetic acid (2,4-D) and (4-chloro-2-methylphenoxy)acetic acid (MCPA) top
Cell parametersNH4+ 3,5-D-.0.5H2OK+ 3,5-D-.0.5H2ORb+ 3,5-D-.0.5H2ONH4+ 2,4-D-.0.5H2OK+ 2,4-D-.0.5H2ORb+ 2,4-D-.0.5H2ONH4+ MCPA-.0.5H2O
a39.818 (3)39.274 (2)39.641 (3)39.3338 (8)36.80 (1)37.254 (2)38.0396 (9)
b4.3340 (4)4.3327 (3)4.3302 (3)4.3889 (9)4.339 (1)4.3589 (3)4.456 (5)
c12.7211 (8)12.4234 (10)12.8607 (8)12.900 (3)12.975 (7)13.238 (1)12.944 (5)
β (°)98.098 (5)99.363 (6)98.404 (5)103.83 (3)102.03 (4)103.231 (7)104.575 (5)
V2178.4 (5)2085.8 (3)2183.9 (3)2074.7 (8)2026 (2)2092.6 (3)2123 (3)
Z8888888
Space groupC2/cC2/cC2/cC2/cC2/cC2/cC2/c
ReferenceSmith (2015b)This work (I)This work (II)Liu et al. (2009)Smith (2015a)Smith (2015a)Smith (2014b)

Experimental details

(I)(II)
Crystal data
Chemical formula[K2(C8H5Cl2O3)2(H2O)][Rb2(C8H5Cl2O3)2(H2O)]
Mr536.26629.00
Crystal system, space groupMonoclinic, C2/cMonoclinic, C2/c
Temperature (K)200200
a, b, c (Å)39.274 (2), 4.3327 (3), 12.4234 (10)39.641 (3), 4.3302 (3), 12.8607 (8)
β (°) 99.363 (6) 98.404 (5)
V (Å3)2085.8 (3)2183.9 (3)
Z44
Radiation typeMo KαMo Kα
µ (mm−1)1.005.01
Crystal size (mm)0.45 × 0.12 × 0.040.40 × 0.12 × 0.04
Data collection
DiffractometerOxford Diffraction Gemini-S CCD-detector
diffractometer		Oxford Diffraction Gemini-S CCD-detector
diffractometer
Absorption correctionMulti-scan
(CrysAlis PRO; Agilent, 2013)		Multi-scan
(CrysAlis PRO; Agilent, 2013)
Tmin, Tmax0.774, 0.9800.369, 0.980
No. of measured, independent and
observed [I > 2σ(I)] reflections		6745, 2061, 1824 7520, 2152, 1910
Rint0.0350.055
(sin θ/λ)max (Å−1)0.6170.617
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.031, 0.076, 1.07 0.040, 0.095, 1.06
No. of reflections20612152
No. of parameters135136
No. of restraints11
H-atom treatmentH atoms treated by a mixture of independent and constrained refinementH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3)0.27, −0.250.98, −1.00

Computer programs: CrysAlis PRO (Agilent, 2013), SIR92 (Altomare et al., 1993), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008) within WinGX (Farrugia, 2012), PLATON (Spek, 2009).

 

Acknowledgements

The author acknowledges financial support from the Science and Engineering Faculty, Queensland University of Technology.

References

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ISSN: 2056-9890
Volume 71| Part 10| October 2015| Pages 1177-1180
doi:10.1107/S2056989015016722
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