catena-Poly[[[triaqua­europium(III)]-μ-(1H-benzimidazole-5,6-dicarboxyl­ato-κ2 O 5:O 6)-μ-(1H,3H-benzimidazol-3-ium-5,6-dicarboxyl­ato-κ3 O 5:O 6,O 6′)] dihydrate]

Xiao-Ye Chen; Shu-Min Huo; Jing-Jun Lin; Xia Cai; Rong-Hua Zeng

doi:10.1107/S1600536811033496

. 2011 Aug 27;67(Pt 9):m1294–m1295. doi: 10.1107/S1600536811033496

catena-Poly[[[triaquaeuropium(III)]-μ-(1H-benzimidazole-5,6-dicarboxylato-κ² O ⁵:O ⁶)-μ-(1H,3H-benzimidazol-3-ium-5,6-dicarboxylato-κ³ O ⁵:O ⁶,O ^6′)] dihydrate]

Xiao-Ye Chen ^a, Shu-Min Huo ^a, Jing-Jun Lin ^a, Xia Cai ^a, Rong-Hua Zeng ^a,^b,^*

PMCID: PMC3200846 PMID: 22058883

Abstract

In the title one-dimensional coordination polymer, {[Eu(C₉H₄N₂O₄)(C₉H₅N₂O₄)(H₂O)₃]·2H₂O}_n, one of the 1H-benzimidazole-5,6-dicarboxylate (Hbdc) ligands is protonated at the imidazole group (H₂bdc). The Eu^III ion is eight-coordinated by two O atoms from two Hbdc ligands, three O atoms from two H₂bdc ligands and three water molecules, showing a distorted square-antiprismatic geometry. The Eu^III ions are bridged by the carboxylate groups of the Hbdc and H₂bdc ligands, forming a chain along [110], with an Eu⋯Eu separation of 5.4594 (3) Å. These chains are further connected by intermolecular O—H⋯O, N—H⋯O and N—H⋯N hydrogen bonds, as well as π–π interactions between the imidazole and benzene rings [centroid–centroid distances = 3.558 (3), 3.906 (2), 3.397 (3), 3.796 (2) and 3.898 (2) Å], into a three-dimensional supramolecular network.

Related literature

For background to 1H-benzimidazole-5,6-dicarboxylate complexes, see: Fu et al. (2009 ▶); Huang et al. (2009 ▶); Pan et al. (2010 ▶); Wei et al. (2009 ▶); Yao et al. (2008 ▶).

Experimental

Crystal data

[Eu(C₉H₄N₂O₄)(C₉H₅N₂O₄)(H₂O)₃]·2H₂O
M _r = 651.33
Triclinic,
a = 8.4530 (4) Å
b = 10.9757 (6) Å
c = 12.7124 (7) Å
α = 112.112 (1)°
β = 91.614 (1)°
γ = 104.453 (1)°
V = 1048.25 (10) Å³
Z = 2
Mo Kα radiation
μ = 3.08 mm⁻¹
T = 298 K
0.24 × 0.22 × 0.20 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2001 ▶) T _min = 0.526, T _max = 0.578
5435 measured reflections
3711 independent reflections
3454 reflections with I > 2σ(I)
R _int = 0.016

Refinement

R[F ² > 2σ(F ²)] = 0.024
wR(F ²) = 0.057
S = 1.04
3711 reflections
328 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.63 e Å⁻³
Δρ_min = −0.67 e Å⁻³

Data collection: APEX2 (Bruker, 2007 ▶); cell refinement: SAINT (Bruker, 2007 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEPIII (Burnett & Johnson, 1996 ▶) and PLATON (Spek, 2009 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablock(s) I, glogal. DOI: 10.1107/S1600536811033496/hy2459sup1.cif

e-67-m1294-sup1.cif^{(25KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811033496/hy2459Isup2.hkl

e-67-m1294-Isup2.hkl^{(181.9KB, 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—H1WA⋯O1	0.85	1.95	2.727 (4)	152
O1W—H1WB⋯O4ⁱ	0.85	1.93	2.709 (4)	152
O2W—H2WA⋯O8	0.85	1.89	2.687 (4)	155
O2W—H2WB⋯O4W	0.85	2.23	2.608 (5)	107
O3W—H3WA⋯O7ⁱⁱ	0.85	2.01	2.815 (4)	159
O3W—H3WB⋯O5Wⁱⁱ	0.85	1.96	2.685 (4)	142
O4W—H4WA⋯O2ⁱⁱⁱ	0.85	2.19	2.968 (4)	153
O4W—H4WB⋯O1W^iv	0.85	2.49	3.022 (4)	122
O4W—H4WB⋯O4ⁱⁱⁱ	0.85	2.37	3.151 (4)	153
O5W—H5WA⋯O5	0.85	1.97	2.815 (4)	172
O5W—H5WB⋯O4^v	0.85	1.99	2.757 (4)	150
N1—H1⋯O1^vi	0.86	2.06	2.900 (4)	165
N3—H3A⋯N2^vii	0.86	1.88	2.725 (5)	168
N4—H4⋯O6^viii	0.86	1.98	2.750 (4)	148

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) ; (v) ; (vi) ; (vii) ; (viii) .

Acknowledgments

The authors acknowledge the Undergraduates Innovating Experimentation Project of Guangdong Province, the Undergraduates Innovating Experimentation Project of South China Normal University and the Students Extracurricular Scientific Research Project of South China Normal University for supporting this work.

supplementary crystallographic information

Comment

There is currently much interest in employing N-heterocyclic carboxylic acids as multidentate ligands to design metal coordination polymers with intriguing structures and potential applications. Particular attention has been paid to 1H-benzimidazole-5,6-dicarboxylic acid (H₃bdc) ligand. It has rich coordination sites (two N atoms and four O atoms) and can be partially or fully deprotonated to produce [H₂bdc]^-, [Hbdc]^2- and [bdc]^3- anions at different pH values. Thus, H₃bdc can potentially afford different coordination modes in multicoordinated ways with transition metal ions (Fu et al., 2009; Wei et al., 2009) or rare earth metal ions (Huang et al., 2009; Pan et al., 2010; Yao et al., 2008) to form metal coordination polymers with various structures and interesting properties. In this paper, we report the crystal structure of the title compound, which was synthesized under hydrothermal conditions.

As shown in Fig. 1, the title compound has two forms of the ligands, [Hbdc]^2- and [H₂bdc]^- anions, and the latter is protonated at the imidazole group. The Eu^III ion is eight-coordinated by five O atoms from two Hbdc and two H₂bdc ligands and by three water molecules. The coordination geometry around the Eu^III ion can be described as distorted square-antiprismatic, with Eu—O bond lengths ranging from 2.343 (2) to 2.656 (3) Å and O—Eu—O bond angles varying from 68.99 (9) to 156.77 (9)°. In the crystal, the Eu^III ions are alternately bridged by the carboxylate groups of the Hbdc and H₂bdc ligands, forming chains along [1 1 0] (Fig. 2). These chains are further connected by intermolecular O—H···O, N—H···O and N—H···N hydrogen bonds (Table 1), as well as π–π interactions between the imidazole and benzene rings [centroid–centroid distances = 3.558 (3), 3.906 (2), 3.397 (3), 3.796 (2) and 3.898 (2) Å], into a three-dimensional supramolecular network (Fig. 3).

Experimental

A mixture of Eu₂O₃ (0.352 g, 1 mmol), H₃bdc (0.206 g, 1 mmol), water (10 ml) in the presence of HClO₄ (0.039 g, 0.385 mmol) was stirred vigorously for 30 min and then sealed in a 20 ml Teflon-lined stainless-steel autoclave. The autoclave was heated and maintained at 443 K for 3 days, and then cooled to room temperature at 5K h^-1. Colorless block crystals of the title compound were obtained.