Poly[[μ10-4,4′-(ethane-1,2-diyldi­oxy)dibenzoato]dipotassium]

Zhen Ma; Baohuan Liang; Wanbing Lu

doi:10.1107/S1600536812008513

. 2012 Mar 3;68(Pt 4):m370. doi: 10.1107/S1600536812008513

Poly[[μ₁₀-4,4′-(ethane-1,2-diyldioxy)dibenzoato]dipotassium]

Zhen Ma ^a,^*, Baohuan Liang ^a, Wanbing Lu ^a

PMCID: PMC3343791 PMID: 22589765

Abstract

The title salt, [K₂(C₁₆H₁₂O₆)]_n, was obtained by the reaction of 1,2-bis[4-(ethyl-carboxyl)-phenoxyl]ethane with KOH in water. The anion lies on a crystallographic inversion center, which is located at the mid-point of the central C—C bond. The K⁺ cation is coordinated by six O atoms, two from the chelating carboxylate group of the anion and four from four neighboring and monodentately binding anions, giving rise to an irregular [KO₆] coordination polyhedron. The coordination mode of the cation leads to the formation of K/O layers parallel to (100). These layers are linked by the nearly coplanar anions (r.m.s. deviation of 0.064 Å of the carboxyl, aryl and O—CH₂ groups from the least-squares plane) into a three-dimentional network.

Related literature

For the preparation, structures, properties and applications of metal carboxylate compounds, see: Ma et al. (2005 ▶); Su et al. (2010 ▶); Zhang & Chen (2008 ▶); Zhu et al. (2008 ▶). For the preparation of the precusor, see: Ma & Yang (2011 ▶). For standard bond lengths, see: Allen et al. (1987 ▶).

Experimental

Crystal data

[K₂(C₁₆H₁₂O₆)]
M _r = 189.23
Monoclinic,
a = 18.0696 (7) Å
b = 3.9866 (1) Å
c = 11.3189 (5) Å
β = 107.188 (2)°
V = 778.96 (5) Å³
Z = 4
Mo Kα radiation
μ = 0.64 mm⁻¹
T = 298 K
0.15 × 0.11 × 0.10 mm

Data collection

Bruker SMART CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.919, T _max = 0.938
7387 measured reflections
2146 independent reflections
1999 reflections with I > 2σ(I)
R _int = 0.018

Refinement

R[F ² > 2σ(F ²)] = 0.023
wR(F ²) = 0.067
S = 1.01
2146 reflections
109 parameters
H-atom parameters constrained
Δρ_max = 0.39 e Å⁻³
Δρ_min = −0.22 e Å⁻³

Data collection: SMART (Bruker, 2001 ▶); cell refinement: SAINT (Bruker, 2002 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: XP in SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: publCIF (Westrip, 2010 ▶).

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812008513/wm2592sup1.cif

e-68-0m370-sup1.cif^{(19.3KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812008513/wm2592Isup2.hkl

e-68-0m370-Isup2.hkl^{(105.5KB, hkl)}

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

Table 1. Selected bond lengths (Å).

K1—O2ⁱ	2.6558 (8)
K1—O1ⁱⁱ	2.6780 (8)
K1—O2	2.7069 (8)
K1—O1ⁱⁱⁱ	2.7167 (8)
K1—O2^iv	2.8027 (8)
K1—O1	3.0335 (8)

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

Acknowledgments

The authors are grateful for financial support from the Scientific Fund of Guangxi University (X061144) and the Opening Project of Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology (K008).

supplementary crystallographic information

Comment

The coordination chemistry of carboxylic compounds is attracting current attention, based on interesting properties like gas adsorption and separation, catalysis, magnetism, luminescence and host-guest chemistry (Su et al., 2010; Zhu et al., 2008) of these compounds. It is well-known that carboxylic acids are excellent building blocks for the construction of coordination polymers, yielding extended frameworks by virtue of their bridging abilities (Ma et al., 2005; Zhang & Chen, 2008). Hence, the present paper aims to promote the search for new metal carboxylic complexes exhibiting special properties in many fields, in particular those bearing multicarboxylic-type ligands, a promising but still rather underdeveloped field of research. We report here the structure of a new polymeric dipotassium dicarboxylic compound (Fig. 1).

In the asymmetric unit one half of the anion is present. The anion lies on a crystallographic inversion center, which is located at the mid point of the C8—C8ⁱ bond (symmetry code (i) = -x-1, -y-1, -z). All bond lengths and angles of the anion are within normal ranges (Allen et al., 1987). The K⁺ ion is coordinated by six oxygen atoms, two from the ligand and four from neighboring ligands, in a distorted [KO₆] polyhedron (Fig 2), whereby one anion coordinates all in all to ten K⁺ cations. The benzene rings of the anion are parallel to each other with a plane-to-plane distance of 3.488 Å. The carboxyl, aryl and O—CH₂ moieties are coplanar with an r.m.s. deviation of 0.0638 Å.

A three-dimensional network is spanned owing to the coordination mode of the potassium cations. The K⁺ cations and the O atoms of the carboxylate anions form a layer parallel to (100). These layers are finally connected by the substituted ethane moieties into a three-dimensional structure (Fig. 2).

Experimental

The precusor of the title compound was prepared by a reported procedure (Ma & Yang, 2011). The title compound was synthesized by the reaction of the precusor, diethyl 4,4'-(ethane-1,2-diyldioxy)-dibenzoate and potassium hydroxide in the conditions as follows: The precusor (1.0 g, 2.8 mM) and KOH (0.31 g, 5.6 mM) were put in water (150 cm³) in a 250 cm³ flask and the system was stirred for 24 h at 373 K for all solids dissolved and cooled down to room temperature. After filtration, a colorless solution was obtained. Evaporation of the solution gave a white solid (0.82 g, 77 %), which was washed with ethanol two times (10 ml each). Slow evaporation of a solution of the title compound in water led to the formation of colorless crystals, which were suitable for X-ray characterization.