Diaqua­bis­(1H-imidazole-κN 3)bis­(4-nitro­benzoato-κO 1)cadmium

Yan-Li Mao; Xiao-Ke Yu; Jian-Li Lin

doi:10.1107/S1600536812033739

. 2012 Aug 4;68(Pt 9):m1149. doi: 10.1107/S1600536812033739

Diaquabis(1H-imidazole-κN ³)bis(4-nitrobenzoato-κO ¹)cadmium

Yan-Li Mao ^a, Xiao-Ke Yu ^a, Jian-Li Lin ^a,^*

PMCID: PMC3435578 PMID: 22969451

Abstract

In the centrosymmetric title compound, [Cd(C₇H₄NO₄)₂(C₃H₄N₂)₂(H₂O)₂], the Cd^II atom, located on an inversion center, is coordinated by two N atoms and four O atoms in an octahedral geometry. The internal cohesion of the molecule is enhanced by an intramolecular O—H⋯O hydrogen bond. Intermolecular O—H⋯O and C—H⋯O hydrogen bonds and π–π contacts [centroid–centroid distance = 3.6549 (2) Å] define two-dimensional networks parallel to (001), which are further connected by weaker C—H⋯O interactions into a weakly connected three-dimensional supramolecular framework.

Related literature

For general background to aromatic carboxyl acid complexes, see: Kuang et al. (2007 ▶); Hsu et al. (2011 ▶). For related structures, see: Zheng et al. (2008 ▶).

Experimental

Crystal data

[Cd(C₇H₄NO₄)₂(C₃H₄N₂)₂(H₂O)₂]
M _r = 614.80
Triclinic,
a = 5.8017 (12) Å
b = 8.0253 (16) Å
c = 12.879 (3) Å
α = 77.99 (3)°
β = 88.42 (3)°
γ = 85.16 (3)°
V = 584.4 (2) Å³
Z = 1
Mo Kα radiation
μ = 1.00 mm⁻¹
T = 293 K
0.33 × 0.14 × 0.09 mm

Data collection

Rigaku R-AXIS RAPID diffractometer
Absorption correction: multi-scan (ABSCOR; Higashi, 1995 ▶) T _min = 0.989, T _max = 0.989
5719 measured reflections
2627 independent reflections
2511 reflections with I > 2σ(I)
R _int = 0.031

Refinement

R[F ² > 2σ(F ²)] = 0.026
wR(F ²) = 0.076
S = 1.24
2627 reflections
175 parameters
3 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.54 e Å⁻³
Δρ_min = −0.80 e Å⁻³

Data collection: RAPID-AUTO (Rigaku, 1998 ▶); cell refinement: RAPID-AUTO; data reduction: CrystalStructure (Rigaku/MSC, 2004 ▶); 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 datablock(s) global, I. DOI: 10.1107/S1600536812033739/bg2473sup1.cif

e-68-m1149-sup1.cif^{(15.7KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812033739/bg2473Isup2.hkl

e-68-m1149-Isup2.hkl^{(129KB, 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—H5A⋯O2	0.84 (1)	1.88 (1)	2.679 (1)	159
O5—H5B⋯O1ⁱ	0.84 (1)	1.97 (1)	2.785 (1)	164
C2—H2A⋯O5ⁱⁱ	0.93	2.58	3.244 (1)	129
C3—H3A⋯O5ⁱⁱⁱ	0.93	2.43	3.344 (1)	169
C10—H10A⋯O2	0.93	2.42	2.751 (4)	101

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

Acknowledgments

This project was supported by the Scientific Research Fund of Ningbo University (grant No. XKL069). Sincere thanks are also extended to the K. C. Wong Magna Fund in Ningbo University.

supplementary crystallographic information

Comment

Aromatic carboxyl acid complexes have been paid great attention these years for their potential applications in gas storage, separation, catalysis, magnetism, luminescence, and drug delivery (Kuang et al., 2007). As a N-containing aromatic carboxyl acid, nitrobenzoic acid has been widely used in dye intermediate, organic synthesis, sensitization material, functional pigment (Hsu et al., 2011). So far, to our knowledge, cadmium complexes constructed from 4-nitrobenzoato and imidazole have not been reported. In order to get new Cd^II complexes with novel functions and discover their structure-property relationship, a new complex [Cd(C₇H₄NO₄)(C₃H₄N₂)(H₂O)] was synthesized.

The asymmetric unit of [Cd(C₇H₄NO₄)(C₃H₄N₂)(H₂O)] consists of a Cd²⁺ ion lying on an inversion centre, a 4-NBA^- ion (4-HNBA = 4-nitrobenzoic acid), one imidazole ligand and one lattice water as illustrated in Fig. 1. The Cd²⁺ cation is octahedrally coordinated by two N atoms of imidazole ligands, two O atoms from two 4-NBA^- ions and two O atoms from two lattice water molecules; it takes a (4 + 2) octahedral geometry, with the oxygen atoms located in the equatorial plane (Cd—O1 = 2.364 (2) Å, Cd—O5 = 2.367 (2) Å, and the two nitrogen atoms occupying the axial position (Cd—N1 = 2.255 (2) Å). Table 1 presents the \p···\p contact information involving the C₃N₂ ring (centroid, Cg1) and Table 2, the more meaningful H-bonds in the structure; the most important ones are those involving water H's. The one described in the first entry in Table 2 is intramolecular; the seocnd one, instead defines chains along a (Figure 2, vertical arrays). The weak one involving C2—H2A (Table 2, third entry) and the π–π contact (Table 1) link chains into a two-dimensional supramolecular network parallel to (001) as illustrated in Figure 2. Finaly, the remaining weak H-bonds link these 2D structures into a 3D supramolecular architecture (Figure 3).

Experimental

Dropwise addition of 1.0 ml (1 M) of K₂CO₃ to a stirred aqueous solution of Cd(CH₃COO)₂.2H₂O (0.266 g, 1.0 mmol) in 10.0 ml of H₂O yielded a fine white precipitate, which was separated by centrifugation and washed with water until no CH₃COO^- anions were detectable in the supernatant. The fresh precipitate was then added to a stirred aqueous solution of 4-nitrobenzoic acid (0.167 g, 1.0 mmol) in C₂H₅OH/H₂O (1:1, 20.0 ml), producing a white suspension, to which imidazole (0.137 g, 2.0 mmol) was added. The mixture was further stirred vigorously for about 0.5 h. After filtration, the white filtrate (pH = 6.59) was maintained at room temperature and colorless crystals were grown.