Diaqua­bis­(5-carb­oxy-2-ethyl-1H-imidazole-4-carboxyl­ato-κ2 N 3,O 4)cobalt(II) trihydrate

Dong-Liang Miao; Shi-Jie Li; Wen-Dong Song; Shao-Wei Tong; Seik Weng Ng

doi:10.1107/S1600536812008902

. 2012 Mar 3;68(Pt 4):m373–m374. doi: 10.1107/S1600536812008902

Diaquabis(5-carboxy-2-ethyl-1H-imidazole-4-carboxylato-κ² N ³,O ⁴)cobalt(II) trihydrate

Dong-Liang Miao ^a, Shi-Jie Li ^b, Wen-Dong Song ^c,^*, Shao-Wei Tong ^a, Seik Weng Ng ^d,^e

PMCID: PMC3343793 PMID: 22589767

Abstract

In the title compound, [Co(C₇H₇N₂O₄)₂(H₂O)₂]·3H₂O, the Co^II cation, located on an inversion center, is N,O-chelated by two 5-carboxy-2-ethyl-1H-imidazole-4-carboxylate anions and further coordinated by two water molecules in a distorted octahedral geometry. Only one carboxy group of the anion is deprotonated, and the two carboxyl groups of the same anion are linked via an intramolecular O—H⋯O hydrogen bond. One of the lattice water molecules is located on an inversion center, its H atom equally disordered over two positions. One of H atoms of another lattice water molecules is also equally disordered over two sites. Water H atoms and the amino H atom all are involved in an intermolecular hydrogen-bonded network in the crystal.

Related literature

For related metal complexes with imidazole-4,5-dicarboxylate ligands, see: Fan et al. (2010 ▶); Li et al. (2011 ▶); Yan et al. (2010 ▶); Song et al. (2010 ▶); He et al. (2010 ▶).

Experimental

Crystal data

[Co(C₇H₇N₂O₄)₂(H₂O)₂]·3H₂O
M _r = 515.30
Triclinic,
a = 7.1615 (14) Å
b = 8.8729 (18) Å
c = 9.3815 (19) Å
α = 66.06 (3)°
β = 88.66 (3)°
γ = 70.97 (3)°
V = 511.0 (3) Å³
Z = 1
Mo Kα radiation
μ = 0.92 mm⁻¹
T = 293 K
0.20 × 0.18 × 0.15 mm

Data collection

Bruker SMART APEXII diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2001 ▶) T _min = 0.781, T _max = 0.781
5086 measured reflections
2319 independent reflections
1578 reflections with I > 2σ(I)
R _int = 0.029

Refinement

R[F ² > 2σ(F ²)] = 0.035
wR(F ²) = 0.102
S = 1.01
2319 reflections
149 parameters
5 restraints
H-atom parameters constrained
Δρ_max = 0.59 e Å⁻³
Δρ_min = −0.73 e Å⁻³

Data collection: APEX2 (Bruker, 2007 ▶); cell refinement: SAINT (Bruker, 2007 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812008902/xu5468sup1.cif

e-68-0m373-sup1.cif^{(18.2KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812008902/xu5468Isup2.hkl

e-68-0m373-Isup2.hkl^{(113.9KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Selected bond lengths (Å).

Co1—O1	2.153 (2)
Co1—O1W	2.064 (2)
Co1—N2	2.123 (2)

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Table 2. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯O2Wⁱ	0.86	1.96	2.786 (4)	160
O3—H3⋯O2	0.85	1.63	2.471 (3)	171
O1W—H1W⋯O4ⁱⁱ	0.85	1.86	2.708 (3)	173
O1W—H2W⋯O3ⁱⁱⁱ	0.85	1.94	2.763 (3)	161
O2W—H3W⋯O1	0.85	2.33	3.077 (4)	147
O2W—H3W⋯O3W	0.85	2.44	3.091 (3)	134
O2W—H4W⋯O2W^iv	0.85	2.04	2.883 (6)	172
O2W—H7W⋯O4^v	0.85	2.35	3.120 (4)	151
O3W—H5W⋯O2^vi	0.85	2.37	3.040 (2)	136
O3W—H6W⋯O1	0.85	2.26	3.031 (2)	151
O3W—H6W⋯O2	0.85	2.43	3.040 (2)	129

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

Acknowledgments

The work was supported by the Nonprofit Industry Foundation of the National Ocean Administration of China (grant No. 2000905021), the Guangdong Chinese Academy of Science Comprehensive Strategic Cooperation Project (grant No. 2009B091300121) and Guangdong Natural Science Fundation (No. 9252408801000002).

supplementary crystallographic information

Comment

Crystal engineering of mental-organic complexes is a very active research field. It is well known that organic ligands play a crucial role in the design and construction of desirable frameworks. In recent years, multifunctional ligands containing N– and O-donors have attracted great attention due to the fact that they may induce diversity in the coordination modes and interesting properties. In our previous work, we have done a lot of research on the design and synthesis of new compounds built from the imidazole derivatives (Fan et al., 2010; Li et al., 2011; He et al., 2010; Song et al., 2010; Yan et al., 2010). To continue our study, we report here the structure of the title Co(II) complex.

As illustrated in Fig. 1, The Co^II ion adopts a slightly distorted octahedral geometry, with two N,O-bidentate ligands ([Co—O = 2.155 (3) Å and Co—N = 2.128 (2) Å) from the imidazoledicarboxylic group at the equatorial positions, the other two oxygen atoms (Co—O = 2.060 (2) Å) from two water molecules occupied the axial position. In the crystal structure, the complex molecules and solvent molecules are linked by O—H···O and N—H···O hydrogen bonds, forming the final three-dimensional supra-molecular network. A lattice water molecule is located on an inversion center, and one H atom of another water molecule was split into two positions with half occupancy.

Experimental

A mixture of Co(NO₃)₂.6H₂O (0.25 mmol, 0.07 g) and 2-ethyl-1H-imidazole-4,5-dicarboxylic acid (0.5 mmol, 0.09 g) in 10 ml of water solution was sealed in an autoclave equipped with a Teflon liner (25 ml) and then heated at 393 K for 2 d. Red crystals were obtained by slow evaporation of the solvent at room temperature with the yeild of 32% based on Co.