catena-Poly[[[aqua­(1,10-phenan­throline)cadmium(II)]-μ-benzene-1,4-dicarboxyl­ato] benzene-1,4-dicarboxylic acid hemisolvate]

Zhuanzhuan Wang; Weihe Han; Zhihong Liu

doi:10.1107/S1600536809000889

. 2009 Jan 14;65(Pt 2):m184–m185. doi: 10.1107/S1600536809000889

catena-Poly[[[aqua(1,10-phenanthroline)cadmium(II)]-μ-benzene-1,4-dicarboxylato] benzene-1,4-dicarboxylic acid hemisolvate]

Zhuanzhuan Wang ^a, Weihe Han ^a, Zhihong Liu ^a,^*

PMCID: PMC2968137 PMID: 21581788

Abstract

A new cadmium(II) coordination polymer, {[Cd(C₈H₄O₄)(C₁₂H₈N₂)(H₂O)]·0.5C₈H₆O₄}_n, has been synthesized under hydrothermal conditions. The asymmetric unit contains one Cd^II atom, one benzene-1,4-dicarboxylate anion, one 1,10-phenanthroline ligand, one coordinated water molecule and half of an uncoordinated benzene-1,4-dicaboxylic acid solvent molecule. The Cd^II atom is in the centre of a monocapped distorted octahedron made up of four O atoms of two chelating benzene-1,4-dicarboxylate anions, one water O atom and two 1,10-phenanthroline N atoms. The metal centres are connected via bis-chelating benzene-1,4-dicarboxylate anions into a zigzag chain structure along [001]. These chains are further connected by O—H⋯O hydrogen bonds between the water molecules and adjacent carboxylate O atoms. Additional O—H⋯O hydrogen bonding between the uncoordinated benzene-1,4-dicaboxylic acid molecules along [010] consolidates the structure.

Related literature

For background to coordination polymers, see: Liang et al. (2002 ▶); McGarrah et al. (2001 ▶); Moulton et al. (2002 ▶); Wu et al. (2007 ▶). Zheng et al. (2004 ▶). For related structures, see: Shi et al. (2004 ▶); Wang et al. (2004 ▶).

Experimental

Crystal data

[Cd(C₈H₄O₄)(C₁₂H₈N₂)(H₂O)]·0.5C₈H₆O₄
M _r = 557.80
Monoclinic,
a = 26.108 (2) Å
b = 9.6928 (10) Å
c = 21.161 (2) Å
β = 126.494 (2)°
V = 4304.9 (7) Å³
Z = 8
Mo Kα radiation
μ = 1.07 mm⁻¹
T = 298 (2) K
0.42 × 0.18 × 0.02 mm

Data collection

Bruker SMART CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2004 ▶) T _min = 0.663, T _max = 0.984
10895 measured reflections
3793 independent reflections
3061 reflections with I > 2σ(I)
R _int = 0.021

Refinement

R[F ² > 2σ(F ²)] = 0.025
wR(F ²) = 0.062
S = 1.07
3793 reflections
309 parameters
H-atom parameters constrained
Δρ_max = 0.57 e Å⁻³
Δρ_min = −0.28 e Å⁻³

Data collection: SMART (Bruker, 2001 ▶); cell refinement: SAINT (Bruker, 2001 ▶); data reduction: SAINT; 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/S1600536809000889/wm2211sup1.cif

e-65-0m184-sup1.cif^{(25.9KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809000889/wm2211Isup2.hkl

e-65-0m184-Isup2.hkl^{(186KB, hkl)}

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

Table 1. Selected bond lengths (Å).

Cd1—O1	2.284 (3)
Cd1—O3	2.357 (2)
Cd1—N2	2.358 (2)
Cd1—N1	2.362 (2)
Cd1—O7	2.375 (2)
Cd1—O4	2.377 (2)
Cd1—O2	2.601 (3)

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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O5—H5⋯O6ⁱ	0.82	1.92	2.728 (3)	167
O7—H7A⋯O2ⁱⁱ	0.85	1.88	2.665 (3)	154
O7—H7B⋯O4ⁱⁱ	0.85	2.28	3.019 (3)	146

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

supplementary crystallographic information

Comment

Carboxylic acid coordination polymers have an important position in coordination chemistry due to their interesting topologies and their potential applications in functional materials (Wu et al., 2007). The coordination ability of the 1,10-phenanthroline ligand stems from its chelate effect which frequently results in the formation of low-dimensional coordination polymers because of its terminal-group effect (Moulton et al., 2002). In this work, we report a new cadmium coordination polymer with a one-dimensional zigzag chain, {[Cd(C₈H₄O₄)(C₁₂H₈N₂)(H₂O)]₂(C₈H₆O₄)}_n, (I), that was synthesized from benzene-1,4-dicarboxylic acid, 1,10-phenanthroline and cadmium nitrate under hydrothermal conditions.

Each [Cd(C₈H₄O₄)(C₁₂H₈N₂)(H₂O)]₂(C₈H₆O₄)] unit is composed of two Cd²⁺ ions, two 1,10-phenanthroline ligands, two benzene-1,4-dicarboxylate anions, two coordinated water molecules, and one uncoordinated neutral benzene-1,4-dicaboxylic acid solvent molecule. The Cd²⁺ ion in the complex is seven-coordinated with four oxygen atoms (O1, O2, O3 and O4) of two chelating bidentate carboxyl groups from two deprotonated benzene-1,4-dicaboxylic acid ligands, one O atom (O7) of a water molecule, and two nitrogen atoms (N1 and N2) from the chelating 1,10-phenanthroline ligand (Fig. 1). The Cd—O bond distances are between 2.284 (2) Å and 2.601 (2) Å, while the Cd—N bond distances are 2.358 (2) Å and 2.362 (2) Å, which all are in agreement with those of other reported Cd—O and Cd—N bond lengths (Wang et al., 2004; Shi et al., 2004). One Cd²⁺ ion connects two benzene-1,4-dicarboxylate ligands, and one benzene-1,4-dicarboxylic acid ligand also connects two Cd²⁺ ions, leading to a zigzag chain along [001], as shown in Fig. 2. These chains are further connected through O—H···O hydrogen bonding interactions between the water molecules and the oxygen atoms of the coordinated carboxyl groups of benzene-1,4-dicarboxylate ligands in neighboring chains to give an extended supramolecular two-dimensional layer structure, as illustrated in Fig. 3. Additional O—H···O hydrogen bonding between the uncoordinated benzene-1,4-dicaboxylic acid molecules along [010] consolidates the structure.

Experimental

All regents used in the synthesis were of analytic grade and were used without further purification. A mixture of Cd(NO₃)₂^.6H₂O (0.3085 g), 1,10-phenanthroline (0.099 g), benzene-1,4-dicarboxylic acid (0.083 g) and water (20 mL) was sealed in a 40 mL stainless steel reactor with a Teflon inlay after adjustment of the pH to 7 by addition of a dilute NaOH solution. The autoclave was heated to 448 K for 6 d, and then cooled to room temperature. Colorless hexagonal-prismatic crystals were obtained. Elemental analysis, calculated: C, 51.68, H, 3.07, N 5.02; found: C, 50.87, H, 3.22, N 4.96.

The title compoud was further characterized by FT-IR spectroscopy (recorded over the 400 to 4000 cm^-1 region on a Nicolet NEXUS 670 spectrometer with KBr pellets at room temperature); by thermogravimetric analysis (TGA) (performed on a Universal V4.1D TA-SDT Q600 thermal analyzer in N₂ atmosphere with a heating rate of 10 °/min) and by its luminescent properties of the solid state under room temperature.

The FT-IR spectrum of the title compound exhibited the following absorption bands that were assigned referring to literature (Liang et al., 2002). A broad band at 3199 cm^-1 corresponds to the O-H stretching vibration of the coordinated water molecule. The peak at 1682 cm^-1 is attributed to the C=O stretching vibration of the carboxylate group, and the peak at 1380 cm^-1 is due to the C-O stretching vibration of carboxylate group. A typical TG curve is shown in Figure 4. It shows that this compound has two steps of mass loss between 55 and 635 °C. The first step is completed at 376 °C, accompanied with 18.05 % mass loss, which is in good agreement with the theoretical mass loss of 18.12 %, corresponding to the evaporation of two water molecules and an uncoordinated neutral 1,4-benzenedecaboxylic acid molecule. In the second step, the mass loss is 70.31 % from 376 to 635 °C, which corresponds to the decomposition of two 1,10-phenanthroline and two deprotonated 1,4-benzenedecaboxylic acid ligands and can be compared with the calculated value of 70.37 %. After the two steps of mass loss, the mass fraction of the residue is 11.44 %, which is in agreement with the calculated mass summation of the remaining CdO (11.51 %). Previous studies have shown that coordination polymers containing zinc and cadmium ions exhibit photoluminescent properties (McGarrah et al., 2001). As shown in Figure 5, upon excitation of the solid sample at 370 nm, it exhibited strong cyan fluorescent emission bands at 504 nm. It is probably due to the (π^*-π) transitions changing into the (π^*-n) transitions after forming the coordination polymer (Zheng et al., 2004).