catena-Poly[[[diaqua­iron(II)]-μ-pyrazine-2,3-dicarboxyl­ato] dihydrate]

Haiyun Xu; Huailing Ma; Maotian Xu; Wenxian Zhao; Baoguo Guo

doi:10.1107/S1600536807064501

. 2007 Dec 6;64(Pt 1):m104. doi: 10.1107/S1600536807064501

catena-Poly[[[diaquairon(II)]-μ-pyrazine-2,3-dicarboxylato] dihydrate]

Haiyun Xu ^a,^*, Huailing Ma ^a, Maotian Xu ^a, Wenxian Zhao ^a, Baoguo Guo ^a

PMCID: PMC2915058 PMID: 21200463

Abstract

The crystal structure of the title compound, {[Fe(C₆H₂N₂O₄)(H₂O)₂]·2H₂O}_n, was synthesized by a diffusion method. It has a one-dimensional polymeric chain structure and the chains are further connected into a three-dimensional structure by hydrogen bonds. The Fe^II ion has a distorted octahedral coordination environment, with two N and two O atoms from the pyrazine-2,3-dicarboxylate ligands in the equatorial plane and with two water molecules in axial positions. The Fe atom lies on a crystallographic centre of symmetry and a twofold rotation axis passes through the pyrazine ring.

Related literature

For related literature, see: Kondo et al. (1999 ▶); Kitaura et al. (2002 ▶); Zheng et al. (2002 ▶); Mao et al. (1996 ▶); Castillo et al. (2003 ▶); Konar et al. (2004 ▶); Muranishi & Okabe (2003 ▶); Richard et al. (1973 ▶); Xiang et al. (2004 ▶); Zou et al. (1999 ▶).

Experimental

Crystal data

[Fe(C₆H₂N₂O₄)(H₂O)₂]·2H₂O
M _r = 294.01
Monoclinic,
a = 12.5650 (2) Å
b = 7.5158 (1) Å
c = 11.8314 (2) Å
β = 110.759 (1)°
V = 1044.77 (3) Å³
Z = 4
Mo Kα radiation
μ = 1.48 mm⁻¹
T = 298 (2) K
0.23 × 0.20 × 0.18 mm

Data collection

Siemens SMART CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.727, T _max = 0.777
5477 measured reflections
1291 independent reflections
1219 reflections with I > 2σ’(I)
R _int = 0.019

Refinement

R[F ² > 2σ(F ²)] = 0.029
wR(F ²) = 0.088
S = 1.03
1291 reflections
80 parameters
H-atom parameters constrained
Δρ_max = 0.59 e Å⁻³
Δρ_min = −0.70 e Å⁻³

Data collection: SMART (Siemens, 1996 ▶); cell refinement: SAINT (Siemens, 1996 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997a ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997a ▶); molecular graphics: SHELXTL (Sheldrick, 1997b ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536807064501/br2063sup1.cif

e-64-0m104-sup1.cif^{(13.5KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536807064501/br2063Isup2.hkl

e-64-0m104-Isup2.hkl^{(63.9KB, 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
O4—H4A⋯O1ⁱ	0.85	2.17	2.890 (3)	142
O4—H4A⋯O2ⁱ	0.85	2.59	3.227 (3)	133
O4—H4B⋯O1ⁱⁱ	0.85	2.20	3.045 (3)	174
O3—H3A⋯O4ⁱⁱⁱ	0.85	2.41	3.210 (3)	156
O3—H3B⋯O2^iv	0.85	1.98	2.720 (2)	145
C3—H3⋯O2^v	0.93	2.51	3.232 (3)	135

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

Acknowledgments

The authors thank the Natural Science Foundation of Henan Province (grant No. 0511020300) for financial support.

supplementary crystallographic information

Comment

Recently, the effective combination of coordination bond and hydrogen bond has been applied in the engineering study of inorganic-organic hybrid material and the construction of metal-organic coordination supramolecular complexes. The suitable organic ligand makes the complex not only to possess novel structure but also produces unique optical, electric and magnetic properties. Pyrazine-2,3-dicarboxylic acid (pzdcH2) has proved to be well suited for the construction of multidimensional frameworks, due to the presence of two adjacent carboxylate groups (O donor atoms) as substituents on the N-heterocyclic pyrazine ring (N donor atoms). A series of one-dimensional, two-dimensional and three-dimensional metal-organic coordination supramolecular complexes have been synthesized and characterized. Now, we report the crystal structure of the title compound (I), and the crystal structure is similar to the structures reported by Mao et al. (1996). In compound 1, the iron atom is hexacoordinate where the sphere about any iron atom includes the N1, N1A, O1, O1A, O3 and O3A atoms. The Fe atom lies on a crystallographic center of symmetry and that the ligand lies on a crystallographic twofold axis. Two coordinated water molecules are on the axis. The coordination distances for the Fe—O1 2.054 (1) Å are similar with the usual carboxyl oxygen to iron distance of 2.091 Å. The pzdc dianion ligands bridge Fe ions to form extended linear chains. In this structure, the pzdc dianion ligand coordinates to two metal centers via chelate interactions involving each nitrogen N(1) and oxygen O(1) from the adjacent carboxylate substituent (Fig. 1). As shown in Fig. 2, the chains are linked in a 3-D surpramolecular network by O—H···O hydrogen-bonding interactions.

Experimental

The title compound was obtained by a diffusion method. In one arm of U-tube was placed (C₆H₂N₂O₄)Na₂ (42 mg, 0.2 mmol) in water/ethanol (1:1; 10 ml) and in the other H₁₂Cl₂O₁₄Fe (73 mg, 0.2 mmol) in water/ethanol (1:1; 10 ml). The red crystals were collected by filtration, washed with distilled water, followed by ethanol and dried under reduced pressure for 2 h.

Analysis found: C 24.39, H 3.41, N 9.26%; C₆H₁₀N₂O₈Fe requires: C 24.51, H 3.43, N 9.53%.