Poly[[dodeca­aqua­bis­(μ3-pyridine-2,6-dicarboxyl­ato)tetra­kis­(μ2-pyridine-2,6-dicarboxyl­ato)tri­calciumdieuropium(III)] 10.5-hydrate]

Fengjuan Shi; Jiguang Deng; Hongxing Dai

doi:10.1107/S1600536812018028

. 2012 Apr 28;68(Pt 5):m685–m686. doi: 10.1107/S1600536812018028

Poly[[dodecaaquabis(μ₃-pyridine-2,6-dicarboxylato)tetrakis(μ₂-pyridine-2,6-dicarboxylato)tricalciumdieuropium(III)] 10.5-hydrate]

Fengjuan Shi ^a, Jiguang Deng ^a, Hongxing Dai ^a,^*

PMCID: PMC3344405 PMID: 22590167

Abstract

In the title compound, {[Ca₃Eu₂(C₇H₃NO₄)₆(H₂O)₁₂]·10.5H₂O}_n, the Eu^III ion is nine-coordinated by three tridentate pyridine-2,6-dicarboxylate (PDA) ligands, forming a [Eu(PDA)₃]³⁻ building block. The Ca²⁺ ions adopt two types of coordination geometries. One Ca²⁺ ion, lying on a twofold rotation axis, is eight-coordinated by four carboxylate O atoms from four PDA ligands and four water molecules, and the other two Ca²⁺ ions, each lying on an inversion center, are six-coordinated by two carboxylate O atoms from two PDA ligands and four water molecules. The carboxylate groups bridge the Eu^III and Ca²⁺ ions into a three-dimensional porous framework, with channels extending along [010] and [001] in which lattice water molecules are located. Two of the lattice water molecules are disordered over two sets of sites with equal occupancy and one water molecule is 0.25-occupied. Numerous O—H⋯O hydrogen bonds involving the water molecules and carboxylate O atoms are present.

Related literature

For 3d–4f and 4d–4f metal complexes with pyridine-2,6-dicarboxylate ligands, see: Zhao et al. (2006 ▶, 2007 ▶, 2011 ▶); Zhao, Zhao et al. (2009 ▶). For Ln–Ba (Ln = lanthanide) complexes with pyridine-2,6-dicarboxylate ligands, see: Zhao, Zuo et al. (2009 ▶).

Experimental

Crystal data

[Ca₃Eu₂(C₇H₃NO₄)₆(H₂O)₁₂]·10.5H₂O
M _r = 1820.14
Monoclinic,
a = 16.070 (4) Å
b = 9.471 (2) Å
c = 23.540 (6) Å
β = 107.685 (4)°
V = 3413.5 (14) Å³
Z = 2
Mo Kα radiation
μ = 2.16 mm⁻¹
T = 113 K
0.20 × 0.19 × 0.16 mm

Data collection

Rigaku Saturn724 CCD diffractometer
Absorption correction: multi-scan (CrystalClear; Rigaku/MSC, 2009 ▶) T _min = 0.672, T _max = 0.724
27531 measured reflections
6015 independent reflections
4964 reflections with I > 2σ(I)
R _int = 0.054

Refinement

R[F ² > 2σ(F ²)] = 0.042
wR(F ²) = 0.094
S = 1.14
6015 reflections
531 parameters
30 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 1.31 e Å⁻³
Δρ_min = −1.29 e Å⁻³

Data collection: CrystalClear (Rigaku/MSC, 2009 ▶); cell refinement: CrystalClear; data reduction: CrystalClear; 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: SHELXTL.

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536812018028/hy2534sup1.cif

e-68-0m685-sup1.cif^{(38.4KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812018028/hy2534Isup2.hkl

e-68-0m685-Isup2.hkl^{(294.4KB, 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
O13—H13A⋯O10ⁱ	0.85 (1)	1.97 (2)	2.796 (6)	163 (5)
O13—H13B⋯O20ⁱⁱ	0.85 (1)	1.85 (1)	2.696 (6)	175 (6)
O14—H14A⋯O16ⁱⁱⁱ	0.85 (1)	1.96 (2)	2.774 (6)	160 (5)
O14—H14B⋯O9ⁱⁱⁱ	0.85 (1)	1.91 (2)	2.723 (5)	160 (5)
O15—H15A⋯O21^iv	0.85 (1)	1.99 (1)	2.839 (6)	172 (6)
O15—H15B⋯O5	0.85 (1)	1.90 (1)	2.734 (5)	165 (5)
O16—H16A⋯O13^iv	0.78 (6)	2.38 (7)	3.079 (6)	150 (6)
O16—H16B⋯O1^iv	0.84 (6)	1.88 (7)	2.704 (6)	169 (6)
O17—H17A⋯O3ⁱⁱⁱ	0.85 (1)	1.91 (1)	2.745 (6)	167 (5)
O17—H17B⋯O19^v	0.85 (1)	1.93 (3)	2.722 (7)	155 (6)
O18—H18A⋯O22′^vi	0.85 (1)	2.37 (6)	2.990 (15)	130 (6)
O18—H18A⋯O22^vi	0.85 (1)	2.16 (7)	2.657 (14)	117 (6)
O18—H18B⋯O4ⁱⁱⁱ	0.85 (1)	1.98 (2)	2.772 (6)	155 (5)
O19—H19A⋯O24^vii	0.86 (1)	2.31 (3)	3.12 (2)	159 (6)
O19—H19B⋯O7^viii	0.85 (1)	2.07 (4)	2.828 (6)	148 (6)
O20—H20A⋯O15	0.85 (1)	2.04 (2)	2.862 (6)	161 (6)
O20—H20B⋯O23	0.85 (1)	2.03 (4)	2.758 (10)	143 (6)
O20—H20B⋯O22′^ix	0.85 (1)	2.32 (4)	3.042 (13)	143 (5)
O21—H21A⋯O11	0.85 (1)	1.94 (2)	2.774 (6)	167 (6)
O21—H21B⋯O17	0.85 (1)	2.42 (4)	3.113 (7)	138 (5)

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

Acknowledgments

This work was supported by the National High Technology Research and Development (863) Key Program of the Ministry of Science and Technology of China (grant No. 2009AA063201).

supplementary crystallographic information

Comment

Pyridine-2,6-dicarboxylic acid (H₂PDA), as a chelating or bridging ligand, has been proven to be an efficient multidentate ligand to construct multidimensional heterometal-organic frameworks with porous structures. Especially, the lanthanide complexes based on H₂PDA show variable structure characters. The PDA anion chelating to a lanthanide ion possesses free carboxylate oxygen atoms, which can coordinate with transition metals. A systematic study of 3d–4f and 4d–4f complexes based on pyridine-2,6-dicarboxylic acid ligand has been undertaken, such as Ln–Mn (Zhao et al., 2006), Ln–Co (Zhao et al., 2007), Ln–Fe (Zhao et al., 2011) and Ln–Ag (Zhao, Zhao et al., 2009). However, the reports of heterometal-organic frameworks associated with lanthanide and alkaline earth ions are rather rare, only Ln–Ba complexes based on pyridine-2,6-dicarboxylic acid ligand were reported (Zhao, Zuo et al., 2009). In this paper, we report the synthesis and crystal structure of the title compound, using the hydrothermal method with pyridine-2,6-dicarboxylic acid.

In the title compound, the Eu^III ion coordinates with three PDA ligands in a tridentate mode, forming a [Eu(PDA)₃]^3- building block. The remaining coordination sites in the [Eu(PDA)₃]^3- unit coordinate with Ca²⁺ ions. The Ca²⁺ ions adopt two types of coordination geometry, as shown in Fig. 1. The coordination environments of Ca1 and Ca3 atoms are similar, each located on an inversion center and coordinated by two carboxylate O atoms and four water molecules, forming [CaO₂(H₂O)₄] building blocks. Ca2 atom lies on a twofold rotation axis and is coordinated by four carboxylate O atoms from four PDA ligands and four water molecules, forming an eight-coordinated [CaO₄(H₂O)₄] building block. Furthermore, Ca2 and Ca1 atoms are bridged by the same PDA ligand. The overall framework can be viewed as the self-assembly of three types of building blocks, [Eu(PDA)₃], [CaO₂(H₂O)₄] and [CaO₄(H₂O)₄]. Each [Eu(PDA)₃] is surrounded by two [CaO₂(H₂O)₄] units and one [CaO₄(H₂O)₄] unit in its vicinity, while each [CaO₂(H₂O)₄] or [CaO₄(H₂O)₄] unit has two [Eu(PDA)₃] and four [Eu(PDA)₃] units as the nearest neighbors. The linkers are carboxylate groups. As a result of this connection, the [CaO₂(H₂O)₄], [CaO₄(H₂O)₄] and [Eu(PDA)₃] building blocks are connected alternately by carboxylate groups, forming a three-dimensional porous framework, with channels extending along [0 1 0] and [0 0 1] (Fig. 2).

Experimental

A mixture of pyridine-2,6-dicarboxylic acid (134 mg, 0.8 mmol), calcium hydroxide (52 mg, 0.7 mmol), europium nitrate hexahydrate (89 mg, 0.2 mmol) and deionized water (10 ml) was placed in a 25 ml Teflon-lined stainless steel autoclave, which was kept at 433 K for 3 days. The resuling colorless block-shaped crystals suitable for X-ray diffraction experiment were collected and washed with deionized water and diethyl ether (yield: 170 mg).