trans-Diaqua­bis[5-carb­oxy-2-(3-pyrid­yl)-1H-imidazole-4-carboxyl­ato-κ2 N 3,O 4]iron(II)

Wei Liu; Gang Zhang; Xia Li; Ben-Lai Wu; Hong-Yun Zhang

doi:10.1107/S1600536809027457

. 2009 Jul 18;65(Pt 8):m938–m939. doi: 10.1107/S1600536809027457

trans-Diaquabis[5-carboxy-2-(3-pyridyl)-1H-imidazole-4-carboxylato-κ² N ³,O ⁴]iron(II)

Wei Liu ^a, Gang Zhang ^a, Xia Li ^a,^*, Ben-Lai Wu ^b,^*, Hong-Yun Zhang ^b

PMCID: PMC2977312 PMID: 21583390

Abstract

In the title complex, [Fe(C₁₀H₆N₃O₄)₂(H₂O)₂], the Fe^II atom is located on an inversion centre and is trans-coordinated by two N,O-bidentate 5-carboxy-2-(3-pyridyl)-1H-imidazole-4-carboxylate ligands and two water molecules, defining a distorted octahedral environment. A two-dimensional network of N—H⋯O and O—H⋯O hydrogen bonds extending parallel to (110) helps to stabilize the crystal packing.

Related literature

N-Heterocyclic carboxylic acids are efficient N/O donors exhibiting versatile coordination modes and hydrogen bonding and can be successively deprotonated, resulting in a large diversity of supramolecular architectures, see: Gu et al. (2007 ▶); Liu et al. (2004 ▶); Maji et al. (2005 ▶); Rajendiran et al. (2003 ▶); Sun et al. (2005 ▶); Zou et al. (2005 ▶).

Experimental

Crystal data

[Fe(C₁₀H₆N₃O₄)₂(H₂O)₂]
M _r = 556.24
Triclinic,
a = 7.0100 (14) Å
b = 8.6670 (17) Å
c = 9.4110 (19) Å
α = 82.28 (3)°
β = 83.84 (3)°
γ = 70.66 (3)°
V = 533.41 (18) Å³
Z = 1
Mo Kα radiation
μ = 0.78 mm⁻¹
T = 173 K
0.29 × 0.24 × 0.19 mm

Data collection

Rigaku Mercury CCD diffractometer
Absorption correction: multi-scan (CrystalClear; Rigaku, 2000 ▶) T _min = 0.826, T _max = 0.890
4126 measured reflections
2084 independent reflections
1693 reflections with I > 2σ(I)
R _int = 0.023

Refinement

R[F ² > 2σ(F ²)] = 0.038
wR(F ²) = 0.105
S = 1.04
2084 reflections
172 parameters
1 restraint
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.47 e Å⁻³
Δρ_min = −0.55 e Å⁻³

Data collection: CrystalClear (Rigaku, 2000 ▶); 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: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809027457/bv2118sup1.cif

e-65-0m938-sup1.cif^{(18.5KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809027457/bv2118Isup2.hkl

e-65-0m938-Isup2.hkl^{(102.5KB, 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
N2—H2A⋯O4ⁱ	0.83	2.09	2.852 (3)	152
O5—H5A⋯O3ⁱⁱ	0.89	2.03	2.899 (3)	165
O5—H5B⋯N3ⁱⁱⁱ	0.84	2.01	2.780 (3)	152
O3—H3A⋯O2	0.868 (10)	1.613 (11)	2.479 (3)	176 (3)

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

Acknowledgments

This work was supported by the National Natural Science Foundation of China (20771094, 20671083), the Science and Technology Key Task of Henan Province (0524270061) and the China Postdoctoral Science Foundation (20070410877).

supplementary crystallographic information

Comment

N-Heterocyclic carboxylic acids, such as imidazole-4,5-dicarboxylic acid (H₃IDC), are recognized as efficient N/O donors exhibiting versatile coordination modes and hydrogen bonding. It can be successively deprotonated to generate various species with different proton numbers (H₂IDC^-, HIDC^2-, and IDC^3-), and hence may result in a large diversity of supramolecular architectures (Sun et al., 2005; Maji et al., 2005; Liu et al., 2004; Zou et al., 2005; Rajendiran et al., 2003; Gu et al., 2007). In contrast to the well studied H₃IDC, 2-(pyridin-4-yl)-1H-imidazole-4,5-dicarboxylate acid (H₃PIDC), a very close analogue of H₃IDC, still remains unexplored till now. We report here the single-crystal structure of a new compound, [Fe(H₂PIDC)₂(H₂O)₂] (I), in which the H₂PIDC monoanion coordinates to the Fe atom, acting as a bidentate ligand.

As shown in Fig. 1, the molecule of (I) is a discrete neutral monomer, in which the Fe atom resides on a crystallographic inversion centre and the asymmetric unit contains one-half of the [Fe(H₂PIDC)₂(H₂O)₂] formula unit. Each Fe atom is six-coordinated by two N and two O atoms from two H₂PIDC ligands and two water molecule in a highly distorted octahedral geometry. In this complex, the carboxylic acid (H₃PIDC) ligand is singly deprotonated and bears a formal charge of -1, and the uncoordinated carboxylate atoms O3 and O2 form an intramolecular hydrogen bond (Table 1). All non-H atoms in the imidazole-4,5-dicarboxyl group are nearly coplanar [the mean deviation is 0.031 (9) Å], and the dihedral angle between imidazole group and pyridine group is 22.6 (1) °. At list in Table 2, a two-dimensional supramolecular layer is constructed via hydrogen-bonding interactions involving the coordinated water molecules, the carboxy O atoms and the protonated imidazole N atoms (Fig.2), and these two-dimensional layers are parallel arranged along b axis (Fig. 3).

Experimental

A mixture of Fe(II) sulfate (0.056 g, 0.2 mmol), 2-(pyridin-3-yl)-1H-imidazole-4,5-dicarboxylic acid (0.047 g, 0.2 mmol) and water (10 ml) was sealed into a Teflon-lined stainless autoclave and heated at 433 K for 4 days. The bomb was allowed to cooled to room temperature gradually and red prismatic crystals of (I) were obtained. Analysis calculated for C₂₀H₁₆FeN₆O₁₀: C 43.19, H 2.90, N 15.11; found: C 43.12, H 2.94, N 15.13.