Aqua­[bis­(2-ethyl-5-methyl-1H-imidazol-4-yl-κN 3)methane]­oxalatocopper(II) dihydrate

Yang-Hui Luo; Xiao-Min Qian; Ge Gao; Jin-Feng Li; Shu-Lin Mao

doi:10.1107/S1600536811001012

. 2011 Jan 15;67(Pt 2):m172. doi: 10.1107/S1600536811001012

Aqua[bis(2-ethyl-5-methyl-1H-imidazol-4-yl-κN ³)methane]oxalatocopper(II) dihydrate

Yang-Hui Luo ^a,^*, Xiao-Min Qian ^a, Ge Gao ^a, Jin-Feng Li ^a, Shu-Lin Mao ^a

PMCID: PMC3051616 PMID: 21522849

Abstract

In the title compound, [Cu(C₂O₄)(C₁₃H₂₀N₄)(H₂O)]·2H₂O, the Cu^II atom exhibits a distorted square-pyramidal geometry with the two N atoms of the imidazole ligand and the two O atoms of the oxalate ligand forming the basal plane, while the O atom of the coordinated water molecule is in an apical position. The Cu^II atom is shifted 0.232 (2) Å out of the basal plane toward the water molecule. The asymmetric unit is completed by two solvent water molecules. These water molecules participate in the formation of an intricate three-dimensionnal network of hydrogen bonds involving the coordinated water molecule and the NH groups.

Related literature

For the chemical properties of imidazole derivatives, see: Bouwman et al. (2000 ▶). For synthesis, see: Delgado et al. (2008 ▶). For related structures, see: Beznischenko et al. (2007 ▶); Pajunen (1981 ▶).

Experimental

Crystal data

[Cu(C₂O₄)(C₁₃H₂₀N₄)(H₂O)]·2H₂O
M _r = 437.94
Monoclinic,
a = 12.1711 (13) Å
b = 23.167 (2) Å
c = 7.4400 (8) Å
β = 107.304 (1)°
V = 2002.9 (4) Å³
Z = 4
Mo Kα radiation
μ = 1.13 mm⁻¹
T = 298 K
0.35 × 0.18 × 0.12 mm

Data collection

Rigaku Mercury CCD area-detector diffractometer
Absorption correction: multi-scan (CrystalClear; Rigaku, 2005 ▶) T _min = 0.693, T _max = 0.876
10119 measured reflections
3528 independent reflections
1958 reflections with I > 2σ(I)
R _int = 0.071

Refinement

R[F ² > 2σ(F ²)] = 0.045
wR(F ²) = 0.092
S = 0.81
3528 reflections
248 parameters
H-atom parameters constrained
Δρ_max = 0.34 e Å⁻³
Δρ_min = −0.31 e Å⁻³

Data collection: CrystalClear (Rigaku, 2005 ▶); 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: ORTEPIII (Burnett & Johnson, 1996 ▶), ORTEP-3 for Windows (Farrugia, 1997 ▶) and PLATON (Spek, 2009 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811001012/dn2649sup1.cif

e-67-0m172-sup1.cif^{(20KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811001012/dn2649Isup2.hkl

e-67-0m172-Isup2.hkl^{(173KB, 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
O5—H51⋯O4ⁱ	0.85	2.58	3.177 (4)	128
O5—H52⋯O4ⁱⁱ	0.85	1.90	2.748 (4)	174
N2—H2⋯O2ⁱⁱⁱ	0.86	2.09	2.943 (4)	171
N4—H4⋯O7	0.86	2.03	2.847 (4)	158
O6—H6F⋯O5^iv	0.85	2.50	3.259 (4)	149
O6—H6G⋯O4^v	0.85	2.30	3.057 (5)	148
O7—H7C⋯O3^vi	0.85	2.03	2.882 (4)	178
O7—H7D⋯O6	0.85	1.97	2.818 (4)	177

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

supplementary crystallographic information

Comment

Imidazole derivatives are versatile ligands towards transition metal ions both in man-made and natural systems. They are not only used for catalytic and biocatalysts but also for dioxygen transport and electron storage (Bouwman et al., 2000). As part of our interest in imidazole derivatives, we report here the crystal structure of a new copper complex.

The structure around Cu^II is best decribed as distorted square pyramid environnement with the two N atoms of the imidazole ligand and the two O atoms of the oxalate forming the basal plane whereas the oxygen atom of the coordinated water molecule is in apical position. As expected, the copper atom is shifted ca 0.232 (2)Å out of the basal plane toward the water molecule. The asymmetric unit is completed by two solvate water molecules. The distances and angles within the square pyramid framework agree with related structures (Beznischenko et al., 2007); Pajunen, 1981).

These water molecules participate to the formation of an intricated hydrogen bonds resulting in three dimensionnal network involving the coordinated water molecule and the NH groups (Table 1, Fig. 2).

Experimental

Crystals of the title compound were synthesized by the reaction between copper(II) nitrate trihydrate, potassium oxalate and 4,4'-methanediylbis(2-ethyl-5-methyl-1H-imidazole) ligand. Copper salt and oxalate chemicals used (reagent grade) were commercially available, the 4,4'-methanediylbis(2-ethyl-5-methyl-1H-imidazole) ligand was synthesized as described below . 0.2 mmol(48.4 mg) solid copper(II) nitrate trihydrate was added to a 15 ml aqueous solution of 0.1 mmol(16.6 mg) potassium oxalate under continuous stirring. The suspension was heated at 40–50 °C during 1 h. Then this suspension was mixed with a 5 ml EtOH solution of 0.1 mmol(23.2mg)4,4'-methanediylbis(2-ethyl-5-methyl-1H-imidazole). Finally, the blue solution which results from the mixture was filtered off and allowed to evaporate at room temperature(Delgado, et al.,2008). Single crystals of the title compound as blue prisms were grown from the solution by slow evaporation at room temperature within a few days.

The ligand 4,4'-methanediylbis(2-ethyl-5-methyl-1H-imidazole) was synthesized as follows: 4.35 g (30 mmol) 2-ethyl-5-methylimidazole was added to a solution of 1.5 g (15 mmol)glycine (40% in H₂O). This suspension was vigorously stirred, and 3.1 g (30 mmol) formaldehyde (37% in H₂O) was added dropwise. The resulting turbid mixture was made alkaline with a concentrated sodium hydroxide solution until a pH of 12 was reached(Bouwman, et al.,2000). The reaction mixture was stirred for 8 days at room temperature in a closed vessel. During which time a white solid formed. The white solid was collected by filtration, washed with acetonitrile and diethyl ether, and air-dry at room temperature.