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TRUCTURE OF ORGANIC COMPOUNDS

A Three-Dimensional Coordination Polymer Based on 1,2,3-Triazole-4,5-dicarboxylic Acid (H3tda): {[Cd12(tda)8(H2O)11] · (H2O)6.25}n1 Xin-Hui Zhou* and Qiang Chen Key Laboratory for Organic Electronics and Information Displays and Institute of Advanced Materials, National Jiangsu Syngerstic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts and Telecommunications, Nanjing, 210023, China *e-mail: [email protected] Received October 22, 2015

Abstract—The title coordination polymer {[Cd12(tda)8(H2O)11] · (H2O)6.25}n (H3tda = 1,2,3-triazole-4,5dicarboxylic acid), has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Complex crystallizes in orthorhombic sp. gr. Pmn21 with Z = 4. The Cd2 unit doublebridged by one carboxylate oxygen atom and two neighboring nitrogen atoms from the tda3– ligands are linked by the tda3– ligands to lead to the 2D (4,4) network in the ac plane. The almost coplanar Cd2(μ5-tda)2 unit comprised of two Cd ions double-bridged by two tda3– ligands through the neighboring nitrogen atoms is connected with the other four Cd2(μ5-tda)2 units form the undulating 2D network in the ac plane. The (4,4) networks and undulating 2D networks are alternatively connected along the b axis by the tda3– ligands coordinating to the Cd ions to form the 3D framework. DOI: 10.1134/S106377451702033X

INTRODUCTION Coordination polymers (CPs), which are a kind of coordination compounds with repeating coordination entities extending in 1, 2, or 3 dimensions [1] and composed of metal ions and organic ligands, have received great attention due to their inorganic-organic hybrid nature, order and modification in structure, interesting properties and potential applications in material science such as detection [2, 3], catalysis [4, 5], gas storage [6, 7], magnetism [8], adsorption and separation [9, 10], nano-materials [11, 12], etc. So far, the hydrothermal or solvothermal syntheses, which are self-assembly processes of the various components under high temperature and high pressure, are the major synthetic method for the preparations of CPs. The self-assembly can be affected by several factors, such as temperature, coordination nature of ligand, solvent systems, counterions, and so on [13, 14]. Among all of the factors, the ligand is the most important influencing factor manipulating the structures and properties of CPs. The porous coordination polymers, also known as metal-organic frameworks (MOFs), possess the fascinating properties due to the channels or cavities in the architecture. However, the existence of the channels or cavities in the architecture often reduces the stability of the skeleton, because the 1 The article is published in the original.

release of guest molecules leads to the collapse or deformation of the structure. In some cases, the dense structures are expected to be obtained, instead of the porous ones. The sensible selection for the organic ligands is vital to obtain the dense architecture for