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

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ISSN: 2056-9890

Poly[μ-aqua-bis­­(μ5-2,4-di­chloro­benzoato)dipotassium]

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

(Received 3 December 2013; accepted 10 December 2013; online 18 December 2013)

In the title compound, [K2(C7H3Cl2O2)2(H2O)]n, the potassium salt of 2,4-di­chloro­benzoic acid, the repeating unit in the polymeric structure consists of two identical irregular KO6Cl units related by twofold rotational symmetry, linked by a bridging water mol­ecule lying on the twofold axis. The coordination polyhedron about the K+ ion comprises a carboxyl­ate O atom and a Cl-atom donor from a bidentate chelate ligand inter­action, four O-atom donors from a doubly bridging bidentate carboxyl­ate O,O′-chelate inter­action and the water mol­ecule. A two-dimensional polymeric structure lying parallel to (100) is generated through a series of conjoined cyclic bridges between K+ ions and is stabilized by water–carboxyl­ate O—H⋯O hydrogen-bonding inter­actions.

Related literature

For the structures of potassium salts with coordinating carbon-bound Cl ligands, see: Gowda et al. (2007[Gowda, B. T., Babitha, K. S., Svoboda, I. & Fuess, H. (2007). Acta Cryst. E63, m2222.]); Molčanov et al. (2011[Molčanov, K., Kojić-Prodić, B., Bakić, D., Zilic, D. & Rakvin, B. (2011). CrystEngComm, 13, 5170-5178.]). For an analogous complex with a Cs—Cl bond in a bidentate chelate mode, see: Smith (2013[Smith, G. (2013). Acta Cryst. E69, m628.]). For the structure of ammonium 2,4-di­chloro­benzoate, see: Smith (2014[Smith, G. (2014). In preparation.]).

[Scheme 1]

Experimental

Crystal data
  • [K2(C7H3Cl2O2)2(H2O)]

  • Mr = 476.20

  • Monoclinic, C 2/c

  • a = 31.520 (2) Å

  • b = 4.3407 (3) Å

  • c = 12.7849 (9) Å

  • β = 94.427 (6)°

  • V = 1744.0 (2) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 1.18 mm−1

  • T = 200 K

  • 0.35 × 0.35 × 0.04 mm

Data collection
  • Oxford Diffraction Gemini-S CCD diffractometer

  • Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2012[Agilent (2012). CrysAlis PRO. Agilent Technologies Ltd, Yarnton, England.]) Tmin = 0.706, Tmax = 0.980

  • 9909 measured reflections

  • 1714 independent reflections

  • 1534 reflections with I > 2σ(I)

  • Rint = 0.084

Refinement
  • R[F2 > 2σ(F2)] = 0.031

  • wR(F2) = 0.081

  • S = 1.09

  • 1714 reflections

  • 114 parameters

  • H-atom parameters constrained

  • Δρmax = 0.37 e Å−3

  • Δρmin = −0.23 e Å−3

Table 1
Selected bond lengths (Å)

K1—O1W 2.7597 (12)
K1—O12 2.7443 (15)
K1—Cl2i 3.2670 (7)
K1—O12i 2.7699 (15)
K1—O11ii 3.0826 (14)
K1—O12ii 2.8168 (14)
K1—O11iii 2.7815 (15)
Symmetry codes: (i) x, y+1, z; (ii) -x, -y+1, -z+1; (iii) [x, -y+1, z-{\script{1\over 2}}].

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
O1W—H11W⋯O11iv 0.81 1.92 2.7271 (19) 169
Symmetry code: (iv) [x, -y, z-{\script{1\over 2}}].

Data collection: CrysAlis PRO (Agilent, 2012[Agilent (2012). CrysAlis PRO. Agilent Technologies Ltd, Yarnton, England.]); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: 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.]); molecular graphics: PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]); software used to prepare material for publication: PLATON.

Supporting information


Comment top

The structural references for 2,4-dichlorobenzoic acid (2,4-CLBA) or its compounds are absent from the crystallographic literature. The reaction of 2,4-CLBA with potassium carbonate in aqueous ethanol afforded crystals of the title salt, [K2(C7H3Cl2O2)2(H2O)]n, and the structure is reported herein.

The repeating unit in the polymeric structure consists of two identical irregular KO6Cl units related by twofold rotational symmetry, linked by a bridging water molecule lying on the twofold axis. The irregular KO6Cl coordination sphere comprises a carboxyl O-atom (O11) and a Cl-atom (Cl2) from a bidentate chelate 2,4-DCBA ligand interaction, four O-atom donors from a doubly bridging bidentate carboxyl O,O'-chelate interaction and the bridging water molecule (O1W) (Fig. 1, Table 1). Polymeric extensions in the layered structure, which lies parallel to (100), are through a series of conjoined ring systems including a centrosymmetric carboxyl O-bridged cage [K1···K1ii = 4.0310 (9) and a doubly bridged water–carboxyl-O cage [K1···K1v = 4.1118 (9) Å] (Figs. 2, 3) [for symmetry code (v): -x, y, -z + 1/2; for symmetry code (ii), see: Table 1].

Coordination complexes involving potassium with aromatic ring-bound Cl donors are uncommon in the crystallographic literature but two polymeric examples have been reported, viz. with 4-chlorobenzenesulfonic acid [K—Cl = 3.4051 (14), 3.4969 (14) Å] (Gowda et al., 2007) and with chloranil [K—Cl = 3.4103 (6), 3.5845 (6) Å] (Molčanov et al., 2011). These values are somewhat larger than those in the title complex [3.2670 (7) Å]. Also, a caesium salt having a Cs—Cl bond in a similar bidentate chelate coordination mode with a 2-chloro-substituted aromatic carboxylate ligand is known (Smith, 2013)

The crystal structure of the title complex polymer is stabilized by intra-sheet waterO—H···Ocarboxyl hydrogen-bonding interactions (Table 2). A relatively short inversion-related Cl4···Cl4 contact [3.5419 (8) Å] is also present. Although the aromatic ring systems stack down [010] (Fig. 3), no inter-ring π···π interactions are present [minimum ring centroid separation = 4.3407 (3) Å, the b-cell parameter].

In the 2,4-DCBA ligand the carboxylate group is significantly rotated out of the plane of the benzene ring [torsion angle C2—C1—C11—O11 = 138.2 (4)°] which is comparable with that in the ammonium salt (also a hemihydrate) [-137.2 (3)°] (Smith, 2014).

Related literature top

For the structures of potassium salts with coordinating carbon-bound Cl ligands, see: Gowda et al. (2007); Molčanov et al. (2011). For an analogous complex with a Cs—Cl bond in a bidentate chelate mode, see: Smith (2013). For the structure of ammonium 2,4-dichlorobenzoate, see: Smith (2014).

Experimental top

The title compound was synthesized by heating together for 10 minutes, 0.5 mmol of 2,4-dichlorobenzoic acid and 0.5 mmol of K2CO3 in 15 ml of 10% ethanol–water at boiling temperature. Partial room temperature evaporation of the solution gave colourless crystal plates of the title complex from which a specimen was cleaved for the X-ray analysis.

Refinement top

Carbon-bound hydrogen atoms were placed in calculated positions [C—H = 0.95 Å] and allowed to ride in the refinement, with Uiso(H) = 1.2Ueq(C). The hydrogen atom of the coordinating water molecule was located in a difference-Fourier synthesis but was subsequently allowed to ride, with Uiso(H) = 1.5Ueq(O).

Computing details top

Data collection: CrysAlis PRO (Agilent, 2012); cell refinement: CrysAlis PRO (Agilent, 2012); data reduction: CrysAlis PRO (Agilent, 2012); 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).

Figures top
[Figure 1] Fig. 1. The configuration and atom-numbering scheme for the coordination polyhedron of the title complex, with non-H atoms drawn as 40% probability displacement ellipsoids. The bridging water molecule (O1W) lies on a twofold rotation axis. For symmetry codes, see: Table 1.
[Figure 2] Fig. 2. A partial expansion of the KO6Cl coordination sphere in the polymeric structure. Probability code as in Fig. 1. For symmetry code (v): -x, y, -z + 1/2. For other symmetry codes, see: Table 1.
[Figure 3] Fig. 3. The packing of the structure in the unit cell viewed down [100]. Hydrogen-bonding associations are shown as dashed lines.
Poly[µ-aqua-bis(µ5-2,4-dichlorobenzoato)dipotassium] top
Crystal data top
[K2(C7H3Cl2O2)2(H2O)]F(000) = 952
Mr = 476.20Dx = 1.814 Mg m3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2ycCell parameters from 2539 reflections
a = 31.520 (2) Åθ = 3.6–28.5°
b = 4.3407 (3) ŵ = 1.18 mm1
c = 12.7849 (9) ÅT = 200 K
β = 94.427 (6)°Plate, colourless
V = 1744.0 (2) Å30.35 × 0.35 × 0.04 mm
Z = 4
Data collection top
Oxford diffraction Gemini-S CCD-detector
diffractometer
1714 independent reflections
Radiation source: fine-focus sealed tube1534 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.084
Detector resolution: 16.077 pixels mm-1θmax = 26.0°, θmin = 3.4°
ω–scansh = 3838
Absorption correction: multi-scan
(CrysAlis PRO; Agilent, 2012)
k = 55
Tmin = 0.706, Tmax = 0.980l = 1515
9909 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) = 0.081H-atom parameters constrained
S = 1.09 w = 1/[σ2(Fo2) + (0.0375P)2 + 0.3668P]
where P = (Fo2 + 2Fc2)/3
1714 reflections(Δ/σ)max < 0.001
114 parametersΔρmax = 0.37 e Å3
0 restraintsΔρmin = 0.23 e Å3
Crystal data top
[K2(C7H3Cl2O2)2(H2O)]V = 1744.0 (2) Å3
Mr = 476.20Z = 4
Monoclinic, C2/cMo Kα radiation
a = 31.520 (2) ŵ = 1.18 mm1
b = 4.3407 (3) ÅT = 200 K
c = 12.7849 (9) Å0.35 × 0.35 × 0.04 mm
β = 94.427 (6)°
Data collection top
Oxford diffraction Gemini-S CCD-detector
diffractometer
1714 independent reflections
Absorption correction: multi-scan
(CrysAlis PRO; Agilent, 2012)
1534 reflections with I > 2σ(I)
Tmin = 0.706, Tmax = 0.980Rint = 0.084
9909 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0310 restraints
wR(F2) = 0.081H-atom parameters constrained
S = 1.09Δρmax = 0.37 e Å3
1714 reflectionsΔρmin = 0.23 e Å3
114 parameters
Special details top

Geometry. Bond lengths, 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 e.s.d.'s 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 > 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 (Å2) top
xyzUiso*/Ueq
K10.03304 (1)0.72596 (10)0.39507 (3)0.0247 (2)
Cl20.12895 (2)0.01261 (12)0.42912 (4)0.0310 (2)
Cl40.25235 (1)0.66649 (13)0.63591 (4)0.0323 (2)
O1W0.000000.3018 (4)0.250000.0308 (7)
O110.05794 (4)0.1264 (4)0.69714 (11)0.0316 (5)
O120.04771 (4)0.2297 (3)0.52587 (12)0.0277 (4)
C10.11633 (6)0.3174 (4)0.61306 (15)0.0207 (6)
C20.14444 (6)0.2455 (4)0.53714 (15)0.0216 (6)
C30.18614 (6)0.3470 (5)0.54411 (16)0.0238 (6)
C40.20012 (6)0.5325 (5)0.62714 (16)0.0240 (6)
C50.17357 (6)0.6139 (5)0.70386 (16)0.0279 (6)
C60.13220 (6)0.5016 (5)0.69632 (16)0.0255 (6)
C110.07044 (6)0.2136 (4)0.61080 (16)0.0217 (6)
H30.204800.289900.492600.0290*
H50.183400.743800.760400.0330*
H60.114100.552100.749800.0310*
H11W0.018500.191900.229300.0460*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
K10.0248 (3)0.0267 (3)0.0228 (3)0.0016 (2)0.0024 (2)0.0007 (2)
Cl20.0301 (3)0.0387 (3)0.0251 (3)0.0074 (2)0.0079 (2)0.0099 (2)
Cl40.0208 (3)0.0434 (3)0.0326 (3)0.0062 (2)0.0021 (2)0.0011 (2)
O1W0.0339 (12)0.0233 (11)0.0356 (12)0.00000.0051 (9)0.0000
O110.0290 (8)0.0385 (9)0.0285 (8)0.0052 (7)0.0107 (6)0.0029 (7)
O120.0215 (7)0.0325 (8)0.0289 (8)0.0002 (6)0.0002 (6)0.0023 (6)
C10.0203 (10)0.0220 (10)0.0198 (10)0.0023 (8)0.0022 (7)0.0044 (8)
C20.0248 (10)0.0217 (10)0.0183 (10)0.0010 (8)0.0019 (8)0.0018 (8)
C30.0229 (10)0.0266 (11)0.0226 (10)0.0027 (8)0.0064 (8)0.0021 (9)
C40.0176 (9)0.0287 (11)0.0256 (10)0.0003 (8)0.0019 (8)0.0042 (9)
C50.0261 (11)0.0316 (11)0.0257 (11)0.0028 (9)0.0010 (8)0.0056 (9)
C60.0238 (10)0.0310 (12)0.0222 (10)0.0012 (8)0.0045 (8)0.0032 (9)
C110.0211 (10)0.0180 (9)0.0264 (11)0.0034 (8)0.0042 (8)0.0021 (8)
Geometric parameters (Å, º) top
K1—O1W2.7597 (12)O1W—H11Wiv0.8100
K1—O122.7443 (15)C1—C111.513 (3)
K1—Cl2i3.2670 (7)C1—C21.399 (3)
K1—O12i2.7699 (15)C1—C61.393 (3)
K1—O11ii3.0826 (14)C2—C31.383 (3)
K1—O12ii2.8168 (14)C3—C41.377 (3)
K1—O11iii2.7815 (15)C4—C51.384 (3)
Cl2—C21.7503 (19)C5—C61.389 (3)
Cl4—C41.741 (2)C3—H30.9500
O11—C111.259 (2)C5—H50.9500
O12—C111.256 (2)C6—H60.9500
O1W—H11W0.8100
O1W—K1—O1285.58 (4)K1v—O12—C11122.38 (11)
Cl2i—K1—O1W129.86 (2)K1ii—O12—C1199.47 (12)
O1W—K1—O12i165.73 (4)K1v—O12—K1ii99.05 (4)
O1W—K1—O11ii65.80 (4)K1—O1W—H11W112.00
O1W—K1—O12ii88.98 (3)K1—O1W—H11Wiv115.00
O1W—K1—O11iii70.16 (4)K1iv—O1W—H11W115.00
Cl2i—K1—O1296.15 (3)H11W—O1W—H11Wiv108.00
O12—K1—O12i103.85 (4)K1iv—O1W—H11Wiv112.00
O11ii—K1—O12120.28 (4)C2—C1—C6116.67 (17)
O12—K1—O12ii87.10 (4)C2—C1—C11125.17 (17)
O11iii—K1—O12133.56 (5)C6—C1—C11118.16 (17)
Cl2i—K1—O12i60.61 (3)C1—C2—C3122.28 (18)
Cl2i—K1—O11ii142.72 (4)Cl2—C2—C3116.16 (15)
Cl2i—K1—O12ii141.14 (3)Cl2—C2—C1121.55 (14)
Cl2i—K1—O11iii73.16 (3)C2—C3—C4118.81 (18)
O11ii—K1—O12i100.01 (4)Cl4—C4—C3119.31 (15)
O12i—K1—O12ii80.95 (4)C3—C4—C5121.38 (18)
O11iii—K1—O12i108.77 (5)Cl4—C4—C5119.32 (16)
O11ii—K1—O12ii44.22 (4)C4—C5—C6118.51 (19)
O11ii—K1—O11iii85.62 (4)C1—C6—C5122.31 (18)
O11iii—K1—O12ii129.57 (4)O11—C11—C1115.87 (17)
K1v—Cl2—C2121.60 (7)O12—C11—C1118.73 (17)
K1—O1W—K1iv96.31 (6)O11—C11—O12125.36 (17)
K1ii—O11—C1186.96 (11)C2—C3—H3121.00
K1vi—O11—C11149.09 (14)C4—C3—H3121.00
K1ii—O11—K1vi88.89 (4)C4—C5—H5121.00
K1—O12—C11128.95 (11)C6—C5—H5121.00
K1—O12—K1v103.85 (5)C1—C6—H6119.00
K1—O12—K1ii92.90 (4)C5—C6—H6119.00
O12—K1—O1W—K1iv170.99 (3)K1v—Cl2—C2—C3178.56 (12)
O1W—K1—O12—C11166.16 (15)K1ii—O11—C11—O1220.38 (19)
O1W—K1—O12—K1v10.86 (3)K1ii—O11—C11—C1157.18 (14)
O1W—K1—O12—K1ii89.20 (3)K1vi—O11—C11—O12103.1 (3)
Cl2i—K1—O12—C1136.50 (15)K1vi—O11—C11—C174.5 (3)
Cl2i—K1—O12—K1v118.80 (4)K1—O12—C11—O11124.28 (17)
Cl2i—K1—O12—K1ii141.14 (3)K1—O12—C11—C153.2 (2)
O12i—K1—O12—C1124.70 (16)K1v—O12—C11—O1184.4 (2)
O12i—K1—O12—K1v180.00 (4)K1v—O12—C11—C198.07 (16)
O12i—K1—O12—K1ii79.94 (4)K1ii—O12—C11—O1122.7 (2)
O11ii—K1—O12—C11135.26 (15)K1ii—O12—C11—C1154.80 (13)
O11ii—K1—O12—K1v69.44 (6)C6—C1—C2—Cl2179.26 (15)
O11ii—K1—O12—K1ii30.62 (6)C6—C1—C2—C30.9 (3)
O12ii—K1—O12—C11104.64 (15)C11—C1—C2—Cl21.4 (3)
O12ii—K1—O12—K1v100.06 (5)C11—C1—C2—C3179.75 (18)
O12ii—K1—O12—K1ii0.00 (3)C2—C1—C6—C51.0 (3)
O11iii—K1—O12—C11109.06 (16)C11—C1—C6—C5178.47 (18)
O11iii—K1—O12—K1v46.24 (7)C2—C1—C11—O11138.2 (2)
O11iii—K1—O12—K1ii146.30 (5)C2—C1—C11—O1244.1 (3)
O12—K1—Cl2i—C2i82.73 (8)C6—C1—C11—O1142.5 (2)
O12—K1—O12i—K1i180.00 (5)C6—C1—C11—O12135.27 (19)
O12—K1—O12i—C11i22.63 (14)Cl2—C2—C3—C4179.65 (16)
O12—K1—O11ii—K1iv112.99 (5)C1—C2—C3—C41.9 (3)
O12—K1—O11ii—C11ii36.37 (13)C2—C3—C4—Cl4179.10 (16)
O12—K1—O12ii—K1ii0.00 (4)C2—C3—C4—C51.1 (3)
O12—K1—O12ii—C11ii130.28 (11)Cl4—C4—C5—C6179.16 (16)
O12—K1—O11iii—K1iv105.31 (5)C3—C4—C5—C60.7 (3)
O12—K1—O11iii—C11iii23.1 (3)C4—C5—C6—C11.7 (3)
K1v—Cl2—C2—C10.07 (18)
Symmetry codes: (i) x, y+1, z; (ii) x, y+1, z+1; (iii) x, y+1, z1/2; (iv) x, y, z+1/2; (v) x, y1, z; (vi) x, y+1, z+1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1W—H11W···O11vii0.811.922.7271 (19)169
Symmetry code: (vii) x, y, z1/2.
Selected bond lengths (Å) top
K1—O1W2.7597 (12)K1—O11ii3.0826 (14)
K1—O122.7443 (15)K1—O12ii2.8168 (14)
K1—Cl2i3.2670 (7)K1—O11iii2.7815 (15)
K1—O12i2.7699 (15)
Symmetry codes: (i) x, y+1, z; (ii) x, y+1, z+1; (iii) x, y+1, z1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1W—H11W···O11iv0.811.922.7271 (19)169
Symmetry code: (iv) x, y, z1/2.
 

Acknowledgements

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

References

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