Bis(2-ethyl-1H-imidazol-3-ium) tetra­chloridocuprate(II)

Run-Qiang Zhu

doi:10.1107/S160053681005261X

. 2010 Dec 24;67(Pt 1):m112. doi: 10.1107/S160053681005261X

Bis(2-ethyl-1H-imidazol-3-ium) tetrachloridocuprate(II)

Run-Qiang Zhu ^a,^*

PMCID: PMC3050348 PMID: 21522525

Abstract

In the crystal structure of the title salt, (C₅H₉N₂)₂[CuCl₄], the organic cations and the tetrahedral [CuCl₄] anions are linked into a three-dimensional network by N—H⋯Cl hydrogen bonds. The two 2-ethyl imidazolium cations in the asymmetric unit differ in the orientation of the ethyl group, with N—C—C—C torsion angles of −170.0 (4) and −87.6 (5)°.

Related literature

For general background to ferroelectric metal-organic frameworks, see: Fu et al. (2009 ▶); Ye et al. (2006 ▶); Zhang et al. (2008 ▶, 2010 ▶).

Experimental

Crystal data

(C₅H₉N₂)₂[CuCl₄]
M _r = 399.63
Triclinic,
a = 7.992 (4) Å
b = 9.003 (4) Å
c = 12.216 (6) Å
α = 79.641 (14)°
β = 84.646 (14)°
γ = 72.154 (12)°
V = 822.4 (7) Å³
Z = 2
Mo Kα radiation
μ = 1.97 mm⁻¹
T = 293 K
0.30 × 0.25 × 0.20 mm

Data collection

Rigaku SCXmini diffractometer
Absorption correction: multi-scan (CrystalClear; Rigaku, 2005 ▶) T _min = 0.559, T _max = 0.674
9065 measured reflections
3775 independent reflections
3124 reflections with I > 2σ(I)
R _int = 0.035

Refinement

R[F ² > 2σ(F ²)] = 0.039
wR(F ²) = 0.123
S = 1.17
3775 reflections
174 parameters
H-atom parameters constrained
Δρ_max = 0.59 e Å⁻³
Δρ_min = −0.66 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: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S160053681005261X/vm2067sup1.cif

e-67-0m112-sup1.cif^{(16.3KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S160053681005261X/vm2067Isup2.hkl

e-67-0m112-Isup2.hkl^{(183KB, 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
N1—H1A⋯Cl1ⁱ	0.86	2.39	3.217 (3)	160
N2—H2A⋯Cl2	0.86	2.39	3.195 (3)	157
N3—H3A⋯Cl3	0.86	2.46	3.178 (3)	142
N4—H4C⋯Cl4ⁱⁱ	0.86	2.32	3.149 (3)	164

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

Acknowledgments

This work was supported by Southeast University.

supplementary crystallographic information

Comment

Dielectric constant measurements of compounds as a function of temperature is the basic method to find the materials which possess potential ferroelectric phase changes (Fu et al., 2009; Ye et al., 2006; Zhang et al., 2008; Zhang et al., 2010). The dielectric constant of the title compound has been measured, but showed no dielectric disuniformity in the range 93–365 K (m.p. 374–381 K).

X-ray crystallographic studies have been carried out for the complex 2[C₅N₂H₉] ⁺.CuCl₄^2- at 123 K. An view of the complex is shown in Fig. 1. The structure is consolidated by extensive intermolecular and intramolecular hydrogen bonds between Cl and N. This hydrogen bonding (Table 1, Fig. 2) produces a three-dimensional network. Within the CuCl₄^2- tetrahedra the Cu-Cl distances are: Cu1—Cl1 = 2.2287 (13) Å, Cu1—Cl2 = 2.2625 Å,Cu1—Cl3 = 2.2688 (12) Å, Cu1—Cl4 = 2.2501 (13) Å.

The two 2-ethyl imidazolium cations in the asymmetric unit differ in the orientation of the ethyl group. In one cation all atoms except H atoms are situated in the same plane(dihedral angle N1—C3—C4—C5 = -170.0 (4)°), while in the other cation the dihedral angle N3—C8—C9—C10 is -87.6 (5) °.

Experimental

A mixture of CuCl₂ (4.26 g, 25 mmol), hydrochloric acid (50 mmol), and 2-ethyl imidazole (4.8 g, 50 mmol) in water was stirred for several days at room temperature, yellow block crystals were obtained.