Poly[μ-aqua-μ5-[2-(2,3,6-tri­chloro­phenyl)acetato]-caesium]

Graham Smith

doi:10.1107/S1600536813029395

. 2013 Nov 6;69(Pt 12):m628. doi: 10.1107/S1600536813029395

Poly[μ-aqua-μ₅-[2-(2,3,6-trichlorophenyl)acetato]-caesium]

Graham Smith ^a,^*

PMCID: PMC3884976 PMID: 24454151

Abstract

In the structure of the title complex, [Cs(C₈H₄Cl₃O₂)(H₂O)]_n, the caesium salt of the commercial herbicide fenac [(2,3,6-trichlorophenyl)acetic acid], the irregular eight-coordination about Cs⁺ comprises a bidentate O:Cl-chelate interaction involving a carboxylate-O atom and an ortho-related ring-substituted Cl atom, which is also bridging, a triple-bridging carboxylate-O atom and a bridging water molecule. A two-dimensional polymer is generated, lying parallel to (100), within which there are water–carboxylate O—H⋯O hydrogen-bonding interactions.

Related literature

For background information on the herbicide fenac, see: O’Neil (2001 ▶). For the structure of fenac, see: White et al. (1979 ▶). For examples of caesium complexes involving coordinating carbon-bound Cl, see: Levitskaia et al. (2000 ▶); Smith (2013 ▶). graphic file with name e-69-0m628-scheme1.jpg

Experimental

Crystal data

[Cs(C₈H₄Cl₃O₂)(H₂O)]
M _r = 389.39
Monoclinic,
a = 17.0606 (12) Å
b = 4.9834 (3) Å
c = 13.9283 (10) Å
β = 98.127 (6)°
V = 1172.29 (14) Å³
Z = 4
Mo Kα radiation
μ = 3.82 mm⁻¹
T = 200 K
0.20 × 0.15 × 0.07 mm

Data collection

Oxford Diffraction Gemini-S CCD-detector diffractometer
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2012 ▶) T _min = 0.582, T _max = 0.980
7585 measured reflections
2284 independent reflections
1873 reflections with I > 2σ(I)
R _int = 0.034

Refinement

R[F ² > 2σ(F ²)] = 0.050
wR(F ²) = 0.111
S = 1.09
2284 reflections
136 parameters
H-atom parameters constrained
Δρ_max = 2.18 e Å⁻³
Δρ_min = −1.86 e Å⁻³

Data collection: CrysAlis PRO (Agilent, 2012 ▶); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SIR92 (Altomare et al., 1993 ▶); 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.

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536813029395/wm2781sup1.cif

e-69-0m628-sup1.cif^{(23.3KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536813029395/wm2781Isup2.hkl

e-69-0m628-Isup2.hkl^{(112.3KB, hkl)}

Click here for additional data file.^{(3.5KB, cml)}

Supplementary material file. DOI: 10.1107/S1600536813029395/wm2781Isup3.cml

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Selected bond lengths (Å).

Cs1—Cl6	3.711 (2)
Cs1—O1W	3.131 (6)
Cs1—O13	3.246 (7)
Cs1—Cl6ⁱ	3.646 (2)
Cs1—O1W ⁱ	3.148 (6)
Cs1—O12ⁱⁱ	3.213 (5)
Cs1—O12ⁱⁱⁱ	3.103 (6)
Cs1—O12^iv	3.242 (6)

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) .

Table 2. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1W—H11W⋯O13ⁱⁱ	0.97	1.70	2.638 (8)	161
O1W—H12W⋯O12^v	0.84	2.40	3.191 (8)	158

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Symmetry codes: (ii) Inline graphic ; (v) .

Acknowledgments

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

supplementary crystallographic information

1. Comment

(2,3,6-Trichlorophenyl)acetic acid (fenac) is a commercial herbicide (O'Neil, 2001) and its crystal structure (White et al., 1979) represents the only entry for this compound in the crystallographic literature. My interest in aromatic carboxylic acid herbicides and in polymeric coordination structures of the alkali metal complexes led to the preparation of the title compound, [Cs(C₈H₄Cl₃O₂)(H₂O)]_n, from the reaction of fenac with caesium hydroxide in aqueous ethanol, and the structure is reported herein.

In this structure (Fig. 1), the irregular eight-coordinate CsClO₇ polyhedron comprises a bidentate O:Cl-chelate interaction involving a carboxylate O-atom (O13) and an ortho-related ring substituted Cl-atom (Cl6) which is also bridging, a triple-bridging carboxylate O-atom (O12) and a bridging water molecule O1W (Table 1). A partial expansion of the asymmetric unit in the polymer structure is shown in Fig. 2, forming 4-, 7- and 8-membered cyclic associations linking Cs⁺ ions (a triple bridge involving Cl6, O1W and O12ⁱⁱⁱ, extending down b). The minimum Cs···Cs^vi bridging distance in the structure is 4.4336 (9) Å [for symmetry code (i), see Table 1. For code (vi): -x + 2, y + 1/2, -z + 3/2]. In the Cl bridge, the Cs—Cl bond lengths [3.646 (2) and 3.711 (2) Å] are long compared to those commonly present in the few known examples of caesium complexes having coordinating carbon-bound Cl atoms, e.g. 3.46–3.56 Å for a complex in which 1,2-dichloroethane acts as a bidentate chelate ligand (Levitskaia et al., 2000). However, I have previously reported values similar to those in the title complex in the analogous polymeric structure of caesium 4-amino-3,5,6-trichloropyridine-2-carboxylate monohydrate [3.6052 (11)– 3.7151 (11) Å], in which all three ring-substituted Cl-atoms are coordinated (Smith, 2013).

In the crystal structure of the title complex, a polymer with a sheet structure is generated which lies parallel to (100) (Fig. 3), and within which there are _waterO—H···O_carboxylate hydrogen-bonding interactions (Table 2).

2. Experimental

The title compound was synthesized by heating together under reflux for 10 minutes, 0.5 mmol of (2,3,6-trichlorophenyl)acetic acid and 0.5 mmol of CsOH in 15 ml of 10% ethanol–water. Partial room temperature evaporation of the solution gave thin colourless crystal plates of the title complex from which a specimen was cleaved for the X-ray analysis.