Two Novel Triazole-Based Metal–Organic Frameworks Consolidated by a Flexible Dicarboxylate Co-ligand: Hydrothermal Synthesis, Crystal Structure, and Luminescence Properties

En-Cui Yang; Qing-Qing Liang; Xiu-Guang Wang; Xiao-Jun Zhao

doi:10.1071/CH08147

RESEARCH ARTICLE

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Two Novel Triazole-Based Metal–Organic Frameworks Consolidated by a Flexible Dicarboxylate Co-ligand: Hydrothermal Synthesis, Crystal Structure, and Luminescence Properties

En-Cui Yang ^A , Qing-Qing Liang ^A , Xiu-Guang Wang ^A and Xiao-Jun Zhao ^A ^B

+ Author Affiliations

- Author Affiliations

^A College of Chemistry and Life Science, Key Laboratory of Molecular Structure and Materials Performance, Tianjin Normal University, Tianjin 300387, China.

^B Corresponding author. Email: xiaojun_zhao15@yahoo.com.cn

Australian Journal of Chemistry 61(10) 813-820 https://doi.org/10.1071/CH08147
Submitted: 10 April 2008 Accepted: 27 July 2008 Published: 6 October 2008

Abstract

To explore the effects of a co-ligand on the construction of mixed-ligand metal–organic frameworks (MOFs), two new triazole-based complexes with a flexible dicarboxylate as a co-ligand, {[Zn₄(trz)₄(gt)₂(H₂O)₂](H₂O)₂}_n 1 and {[Cd₂(trz)₂(gt)(H₂O)₂](H₂O)₄}_n 2 (Htrz = 1,2,4-triazole; H₂gt = glutaric acid), were synthesized and their structures were fully characterized by elemental analyses, IR spectroscopy, and single-crystal X-ray crystallography. Their thermal stability and luminescence emissions were further investigated to establish their structure–property relationship. Crystal structure determination showed that 1 is a neutral two-dimensional pillared-bilayer network consisting of 14-membered hydrophobic channels, whereas 2 is an infinite three-dimensional framework constructed from tetranuclear [Cd₄(trz)₄]⁴⁺ subunits. Interestingly, the overall structure of both MOFs can be solely supported by Zn^II/Cd^II and trz anions, and were further consolidated by the introduction of a flexible gt co-ligand. In addition, the carboxylate groups in the co-ligand can also serve as a weak O–H···O hydrogen-bond acceptor to capture guest water molecules. The synchronous weight-loss behaviour of trz and gt anions presented by thermogravometric curves suggest their cooperative contributions to the thermal stability of the MOFs. In contrast, the fluorescence emissions of two complexes are significantly dominated by the core trz ligand, rather than the gt co-ligand and metal ions.

Acknowledgements

This work was financially supported by the National Natural Science Foundation of China (20571056, 20703030), the National Key Fundamental Research Project of China (2005CCA01200), Natural Science Foundation of Tianjin (06YFJMJC03900, 07QTPTJC29800), and Tianjin Educational Committee (20060501, 2006ZD07). The authors also thank Dr Sanjukta Muhuri for her read-through and careful revisions of the manuscript.

References

Two Novel Triazole-Based Metal–Organic Frameworks Consolidated by a Flexible Dicarboxylate Co-ligand: Hydrothermal Synthesis, Crystal Structure, and Luminescence Properties

Abstract

Acknowledgements

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