Elsevier

Inorganica Chimica Acta

Volume 363, Issue 14, 25 November 2010, Pages 3790-3797
Inorganica Chimica Acta

Hydrothermal synthesis, crystal structures and photoluminescent properties of four cadmium(II) coordination polymers derived from diphenic acid and auxiliary ligands

https://doi.org/10.1016/j.ica.2010.05.038Get rights and content

Abstract

Four novel metal coordination polymers, [Cd(dpa)(H2O)]n (1), [Cd(dpa)(2,2′-bipy)]n (2), {[Cd2(dpa)2(4,4′-bipy)3](4,4′-bipy)(H2O)2}n (3) and [Cd(dpa)(bim)2(H2O)]}n (4) (H2dpa = 2,4′-biphenyl-dicarboxylic acid, 2,2′-bipy = 2,2′-bipyridine, 4,4′-bipy = 4,4′-bipyridine, bim = benzimidazole), have been synthesized and structurally characterized by elemental analysis, IR and X-ray diffraction. Single-crystal X-ray analyses reveal that the 2,4′-diphenic acids acts as bridging ligands, exhibiting rich coordination modes to link metal ions: bis-monodentate, bidentate chelating, chelating/bridging, monoatomic bridging and monodentate modes. In addition, the luminescent properties for compound 14 are also investigated in this work.

Graphical abstract

Four new metal coordination polymers have been synthesized and structurally characterized. These coordination polymers have different architecture, such as 1-D helical structure, 2-D layer structure and 2-D microporous structure. Additionally, hydrogen bonding interactions and π–π stacking are found in some structures to further extend or stabilize the coordination motifs.

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Introduction

The interest in the construction of metal–organic frameworks (MOFs) is rapidly increasing due to their diverse structures and potential applications such as gas storage, catalysis, nonlinear optics, molecular magnetism and luminescence [1], [2], [3], [4], [5], [6], [7], [8], [9], [10]. It is well-known that carboxylate-metal compounds exhibit various network topologies and remarkable prospect, therefore the construction of novel coordination polymers using metal ions and anionic O-donor ligands is a hotspot in the field [11], [12], [13], [14], [15]. On the other hand, the introduction of neutral N-donor building block ligands into MOFs provides further impetus for research on metal–organic supramolecular frameworks. Recently, a number of structurally defined new MOFs have been rationally and successfully constructed by using mixed-ligand method [16], [17], [18].

Diphenic acid (H2dpa) as O-donor ligand has received much attention in the designed synthesis of coordination polymers [19], [20], [21], [22], [23], [24], [25], [26], but the MOFs constructed from unsymmetric diphenic acid are less reported [27], [28], [29]. In this paper, we select 2,4′-dpa as the first ligand based on the following considerations: (a) in H2dpa, the two functional groups may have different coordination modes (monodentate, chelating and/or bridging) which allows a wide variety of structures; (b) in deprotonated H2dpa, two phenyl rings are not coplanar with each other owing to the steric hindrance of carboxylate groups in coordination process. The distortion of diphenyl spacer about the central bond allows dpa2− to link metal ions or metal clusters into macrocycles, helical chains and one dimensional chains. Herein, we report the synthesis, crystal structure and luminescent properties of four cadmium coordination polymers based on the 2,4′-diphenic acid or/and auxiliary ligands.

Section snippets

General materials and method

All reagents and solvents employed were commercially available and used as received without further purification. Elemental analysis was carried out on a Carlo Erba 1106 full-automatic trace organic elemental analyzer. FT-IR spectra were recorded with a Bruker Equinox 55 FT-IR spectrometer as a dry KBr pellet in the 400–4000 cm−1 range. Solid-state fluorescence spectra were recorded on a F-4600 equipped with a xenon lamp and a quartz carrier at room temperature.

[Cd(dpa)(H2O)]n (1)

A mixture of Cd(OAc)2·2H2O (0.267 

[Cd(dpa)(H2O)]n (1)

The structure of complex 1 is determined by X-ray single-crystal diffraction. As shown in Fig. 1a, each Cd(II) ion is surrounded by five oxygen atoms from different dpa2− ligands and one oxygen atom from coordinated water molecule in a octahedral coordination geometry. The Cd(1)–O bond lengths vary from 2.214(17) Å to 2.399(16) Å and the O–Cd(1)–O bond angles range from 55.09(6)° to 162.50(7)°. The equatorial plane is defined by four oxygen atoms (the equation of plane is 9.945x + 2.558y + 5.889z = 

Conclusions

Four CdII metal coordination polymers assembled from 2,4′-diphenic acid and auxiliary ligands have been successfully prepared under hydrothermal conditions. In the presence of dpa2− and auxiliary ligands, the assembly of compound 14 gives rise to different frameworks. The results demonstrate that the coordination fashions of organic building blocks play important role in the construction of the metal–organic frameworks. In addition, such compounds also exhibit emission in the solid-state at

Acknowledgements

The authors gratefully acknowledge financial support from the National Natural Science Foundation of China (20971018) and the Scientific Research Development Plan Project of Education Department of Shandong Province (J08LI53).

References (45)

  • R.-H. Wang et al.

    J. Mol. Struct.

    (2006)
  • G.-X. Liu et al.

    Inorg. Chim. Acta

    (2009)
  • G.-C. Liu et al.

    J. Solid State Chem.

    (2009)
  • M. Eddaoudi et al.

    Science

    (2002)
  • S.S. Kaye et al.

    J. Am. Chem. Soc.

    (2007)
  • L. Pan et al.

    Angew. Chem., Int. Ed.

    (2003)
  • B. Moulton et al.

    Chem. Rev.

    (2001)
  • O.R. Evans et al.

    Acc. Chem. Res.

    (2002)
  • O. Kahn

    Acc. Chem. Res.

    (2000)
  • J. Li et al.

    J. Am. Chem. Soc.

    (2007)
  • S. Kitagawa et al.

    Angew. Chem., Int. Ed.

    (2004)
  • S.R. Batten et al.

    Angew. Chem., Int. Ed.

    (1998)
  • M. Eddaoudi et al.

    Acc. Chem. Res.

    (2001)
  • W.L. Liu et al.

    Cryst. Eng. Commun.

    (2008)
  • D.X. Xue et al.

    Cryst. Eng. Commun.

    (2009)
  • C.J. Doonan et al.

    J. Am. Chem. Soc.

    (2009)
  • X.-L. Wang et al.

    Angew. Chem., Int. Ed.

    (2005)
  • X.-Y. Cao et al.

    Cryst. Eng. Commun.

    (2008)
  • X.Y. Cao et al.

    Cryst. Eng. Commun.

    (2008)
  • W.-G. Lu et al.

    Cryst. Growth Des.

    (2008)
  • P.-X. Yin et al.

    Cryst. Growth Des.

    (2009)
  • R.-H. Wang et al.

    Cryst. Growth Des.

    (2005)
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