catena-Poly[[octa­aqua­bis­(μ4-benzene-1,3,5-tricarboxyl­ato)trizinc] tetra­hydrate]

Lin Sun; Tao Run Qiu; Hong Deng

doi:10.1107/S160053681101436X

. 2011 Apr 22;67(Pt 5):m630–m631. doi: 10.1107/S160053681101436X

catena-Poly[[octaaquabis(μ₄-benzene-1,3,5-tricarboxylato)trizinc] tetrahydrate]

Lin Sun ^a, Tao Run Qiu ^a, Hong Deng ^a,^*

PMCID: PMC3089220 PMID: 21754339

Abstract

In the title compound, {[Zn₃(C₉H₃O₆)₂(H₂O)₈]·4H₂O}_n, there are two crystallographically independent Zn^II ions. One presents a trigonal-bipyramidal coordination geometry defined by five O atoms [three from two carboxylate groups of two benzene-1,3,5-tricarboxylate (BTC) ligands and the other two deriving from three water molecules], while the other lies on an inversion centre and exists in a slightly distorted octahedral coordination geometry defined by six O atoms (two from two carboxylate groups of two BTC ligands and the others from four water molecules). A three-dimensional framework is further strengthened via O—H⋯O hydrogen-bonding interactons.

Related literature

For background to the applications of metal–organic frameworks, see: Batten & Murray (2003 ▶); Zhong et al. (2008 ▶); Qiu et al. (2010 ▶). For the applications of benzene-1,3,5-tricarboxylate, see: Yaghi et al. (1997 ▶); Xu et al. (2008 ▶); Xu et al. (2007 ▶); Liang et al. (2009 ▶); Wang et al. (2009 ▶). For compounds exhibiting similar Zn—O distances, see: Hua et al. (2010 ▶); Chen et al. (2010 ▶); Yang et al. (2008 ▶); Xu et al. (2007 ▶).

Experimental

Crystal data

[Zn₃(C₉H₃O₆)₂(H₂O)₈]·4H₂O
M _r = 826.59
Monoclinic,
a = 14.745 (2) Å
b = 6.7960 (12) Å
c = 15.183 (3) Å
β = 94.543 (2)°
V = 1516.7 (4) Å³
Z = 2
Mo Kα radiation
μ = 2.45 mm⁻¹
T = 296 K
0.27 × 0.24 × 0.23 mm

Data collection

Bruker SMART APEX CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.521, T _max = 0.569
7485 measured reflections
2729 independent reflections
1990 reflections with I > 2σ(I)
R _int = 0.047

Refinement

R[F ² > 2σ(F ²)] = 0.064
wR(F ²) = 0.225
S = 1.13
2729 reflections
205 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 1.89 e Å⁻³
Δρ_min = −0.90 e Å⁻³

Data collection: APEX2 (Bruker, 2004 ▶); cell refinement: SAINT (Bruker, 2004 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S160053681101436X/zk2004sup1.cif

e-67-0m630-sup1.cif^{(17.2KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S160053681101436X/zk2004Isup2.hkl

e-67-0m630-Isup2.hkl^{(133.8KB, 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
O4W—H4WB⋯O6ⁱ	0.85	1.97	2.768 (9)	155
O5W—H5WA⋯O2ⁱⁱ	0.85	1.99	2.842 (9)	179
O6W—H6WB⋯O6ⁱⁱⁱ	0.84	2.29	3.058 (13)	153
O5W—H5WB⋯O6^iv	0.85	2.59	3.356 (12)	150

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

Acknowledgments

The authors acknowledge South China Normal University and the National Natural Science Foundation of China, grant No. 20871048, for supporting this work.

supplementary crystallographic information

Comment

The exploring of metal-organic frameworks (MOFs) has attracted considerable attention not only owing to their intriguing structral architectures and topologies, but also because of their many potential applications in catalysis, ion exchange, and magnetic, optical, and porous materials (Batten & Murray, 2003; Zhong et al., 2008; Qiu et al.,2010). 1,3,5-benzenetricarboxylate with six O atoms from its three carboxylate groups is a good choice of O-donor ligand. And such ligand has been widely used to synthesize metal compounds (Yaghi et al., 1997; Xu et al., 2008; Xu et al., 2007; Liang et al., 2009; Wang et al., 2009). Thus, we synthesize a new three-dimensional Zn-BTC metal-organic compound, {[Zn₃(BTC)₂(H₂O)₈](H₂O)₄}, with achiral channels along b direction, which was generated by the reaction of zinc sulfate heptahydrate, 1,3,5-benzenetricarboxylic acid and water at 150°C for 3 days.

There are two kinds of zinc atoms in the title compound (I) (Fig. 1). One is surrounded by five O atoms (three from two carboxylate groups of two BTC ligands and the other two deriving from three water molecules), exhibiting a trigonal bipyramidal geometry, the other is coordinated with six O atoms (two from two carboxylate groups of two BTC ligands; the others from four water molecules) and displays a slightly distorted octahedral geometry. All the BTC ligands have the same coordinated modes and each ligand coordinated to three zinc atoms. The bond distances of Zn—O_{chelated carboxylate} range from 1.999 (5)Å to 2.412 (6) Å. While the bond lengthes of Zn—O_{monodentate carboxylate} fall between 1.946 (6)Å and 2.049 (5) Å. And the Zn—O_w distances are in the normal range of 1.965 (6)–2.150 (6)Å (Table 1). All the distances of Zn—O in compound (I) are comparable to those found in the literatures (Hua et al., 2010; Chen et al., 2010; Yang et al., 2008; Xu et al., 2007). And there are weak interactions between Zn1 and C1 with the distances of 2.554Å and Zn1 and H2WB with with the distances of 2.0711 Å. A three-dimensional architecture is strengthened by the extended O—H···O hydrogen-bonding interactions (Table 2, Fig. 2)

Experimental

A mixture of zinc sulfate heptahydrate (0.287 g; 1 mmol), benzenetricarboxylic acid (0.210 g; 1 mmol) and water (10 ml) was sealed in a 23 ml Teflon-lined stainless steel reactor and heated at 120°C under autogenous pressure for 72 h. Then the mixture was cooled down to room temperature at a rate of 5°C per hour, and colorless block crystals were obtained in a yield of 49% based on Zn