catena-Poly[[aqua­(benzoato-κ2 O,O′)(benzoic acid-κO)calcium]-μ3-benzoato-κ4 O:O,O′:O′]

Olimjon Azizov; Zukhra Kadirova; Tohir Azizov; Samat Tolipov; Bakhtiyar Ibragimov

doi:10.1107/S1600536811013493

. 2011 Apr 16;67(Pt 5):m597. doi: 10.1107/S1600536811013493

catena-Poly[[aqua(benzoato-κ² O,O′)(benzoic acid-κO)calcium]-μ₃-benzoato-κ⁴ O:O,O′:O′]

Olimjon Azizov ^a, Zukhra Kadirova ^b,^*, Tohir Azizov ^a, Samat Tolipov ^c, Bakhtiyar Ibragimov ^c

PMCID: PMC3089294 PMID: 21754317

Abstract

In title compound, [Ca(C₇H₅O₂)₂(C₇H₆O₂)(H₂O)]_n, the eightfold-coordinated Ca^II ion is bonded to four carboxylate O atoms from two benzoate ions, an O atom from benzoic acid and a water O atom. One of the carboxylate groups bridges adjacent Ca²⁺ ions, forming a polymeric ribbon structure parallel to [010]. In the crystal, the benzoate anions and water molecule interact by way of inter- and intramolecular O—H⋯O hydrogen bonds.

Related literature

For background to the crystal structures and physical stability of calcium benzoate hydrates, mesophases and related compounds, see: Cherkezova et al. (1987 ▶); Zhang et al. (1999 ▶); Yano et al. (2001 ▶); Senkovska & Thewalt (2005 ▶); Terakita & Byrn (2006 ▶).

Experimental

Crystal data

[Ca(C₇H₅O₂)₂(C₇H₆O₂)(H₂O)]
M _r = 422.43
Monoclinic,
a = 15.5535 (3) Å
b = 6.61183 (16) Å
c = 20.1828 (4) Å
β = 94.3750 (18)°
V = 2069.49 (8) Å³
Z = 4
Cu Kα radiation
μ = 2.96 mm⁻¹
T = 293 K
0.55 × 0.45 × 0.40 mm

Data collection

Oxford Diffraction Xcalibur Ruby diffractometer
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2007 ▶) T _min = 0.782, T _max = 1.000
7257 measured reflections
3847 independent reflections
2961 reflections with I > 2σ(I)
R _int = 0.025

Refinement

R[F ² > 2σ(F ²)] = 0.041
wR(F ²) = 0.121
S = 1.07
3847 reflections
275 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.27 e Å⁻³
Δρ_min = −0.26 e Å⁻³

Data collection: CrysAlis PRO (Oxford Diffraction, 2007 ▶); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ▶); software used to prepare material for publication: publCIF (Westrip, 2010 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811013493/bv2180sup1.cif

e-67-0m597-sup1.cif^{(20.5KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811013493/bv2180Isup2.hkl

e-67-0m597-Isup2.hkl^{(188.6KB, hkl)}

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

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1W—H1W1⋯O5ⁱ	0.76 (3)	2.05 (3)	2.779 (2)	163 (3)
O1—H1O⋯O6	0.93 (3)	1.68 (3)	2.597 (2)	167 (3)
O1W—H2W1⋯O6ⁱⁱ	0.89 (3)	1.90 (3)	2.754 (2)	159 (3)

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

Acknowledgments

This work was supported by the Grant of Fundamental Research of Centers of Science and Technology, Republic Uzbekistan F 3–142.

supplementary crystallographic information

Comment

The synthesis and structure determination of inorganic polymers are interesting subject for basic inorganic chemistry and materials science. Depending on the pH and other synthetic conditions, many calcium benzoates with different coordination modes, polymeric arrangements and molecular topologies have been observed, e.g. [Ca(C₆H₅COO)₂]×3H₂O(neutral solution; Terakita et al., 2006), Ca(C₆H₅COO)₂](C₆H₅COO)_0.5×2H₂O (acid solution; Cherkezova et al., 1987), [Ca(C₆H₅COO)(H₂O)₃](C₆H₅COO)]_n (basic solution; Senkovska et al., 2005),[Ca(C₆H₅COO)₂(C₃H₇NO)(H₂O)]_n (dimetylformamide solution; Yano et al., 2001), [Ca(C₆H₅COO)₂] (hydrothermal conditions; Zhang et al., 1999).

In this study we synthesized the Ca^II polymeric compound, (I), bridged by a benzoate group, and report the structure of the title compound, (I). The molecular structure is shown on Fig.1 and geometrical parameters are available from archived CIF.

The asymmetric unit of (I) consists of one Ca centre, two benzoate anions, benzoic acid and one water molecule (Fig 1). The calcium ion is surrounded by eight O atoms from two tri- and bidentate benzoates, a monodentate benzoic acid molecule, and a water molecule. The CaO₈ polyhedron deviates extensively from idealized octacoordinated geometries found in other complexes (Senkovska et al., 2005; Yano et al., 2001). There are three different coordination modes of benzoic acid in crystal structure. The tridentate benzoate forms simultaneously the planar four-membered chelate and the buckled four-membered Ca–O–Ca–O rings by bridging adjacent Ca²⁺ ions. The Ca–O bridging bond lengths [2.3204 (14) and 2.3781 (14) Å] are considerably shorter than the Ca–O chelate distances [2.7414 (14) and 2.4567 (14) Å]. The bidentate benzoate has longer Ca–O distances [2.4837 (17) and 2.5628 (15) Å] than observed for monodentate benzoic acid and calcium ion [2.4467 (15) Å].

The bridging interactions and the system of H-bonds form polymeric structure consisted from the infinite ribbons along the b axis and separated by the stacked neighbouring phenyl groups. The benzoic acid hydroxyl group and an water molecule act as H-bond donors, and the O5 and O6 atoms of the bidentate COO^- group are H-bond acceptors. The combination of these hydrogen bonds, π-π stacking interactions and the Ca–O bonds leads to the formation of a two-dimensional network running parallel to the ac-plane (Fig. 2).

Experimental

The Ca(NO₃)₂×4H₂O (1 mmol) and benzoic acid (3 mmol) in 75 ml of ethanol were mixed with the the benzoic acid water solution (2 mmol). The mixture were strirred 6 h at room temperature, and after 3 days the precipitated colourless crystals were filtered off, washed three times with ethanol, dried at room temperature. Crystals of the title compound, suitable to X-ray diffraction analysis, were selected directly from the sample as prepared.