Synthesis, Structure And Properties Of Coordination Polymer Constructed Through Azobenzenetetracarboxylic Acid

The research of supramolecular and metal coordination complexes is involved in many fields including Organic, Inorganic, solid chemistry, and it is the integration of research with foundation and application. Recently, this area has become the advanced study of crystal chemistry and material chemistry in the international. In recent years, much attention has been paid to the designs, syntheses, crystal structures and properties of the carboxylic acid coordination polymer, due to the extensive application of the carboxylic acid coordination polymer, such as catalysis, non-linear optical materials, magnetic materials and porous materials. So, the rational design and coordination polymers based on carboxylate ligand synthesis of novel metal-organic have attracted considerable attention.In this research, six new coordination compounds have been designed and synthesized, with all of them studied systematically by Elemental Analysis and single crystal X-ray diffraction. The results show that the synthesized complexes can be divided into three types, that is one-dimensional (1-D), two-dimensional (2-D) and three-dimensional (3-D) systems. Their crystal structures and spectral properties were characterized.1. Three new compounds on the basis of 3, 3', 4, 4'--azobenzenetetracarboxylic acid (H4ABTC) of different configurations have been room temperature synthesized and structurally characterized including one 2-D layered structures constructed by 3, 3', 4, 4'-azobenzenetetracarboxylic acid, and two 3-D frameworks constructed by transition metals: [C₁₆H₆N_2O8]·2H₂O 1 [Cu(ABTC)_0.5(H₂O)]·0.5H₂O 2 [Cd₂(ABTC) (H₂O)₆] 3 [Mn₂(ABTC)(H₂O)₁₀]·4H₂O 4Compounds 1-4 have two-dimensional and three-dimensional structures that are only constructed by ABTC and transition metals. Compound 1 shows that the structure is conjugated and centrosymmetric, so the molecular structure is coplanar. The ABTC ligands and water molecules form a two-dimensional samdwich. The structure of the compound 2 is an assembling of double layers that stacks as ABAB related by a center of symmetry. The polymer exhibit interesting three-dimensional (3D) mesomeric networks assembled from helix-linked sheets. Compound 3 shows that the structure is one-dimensional polymeric chains of ABTC and Cd. The compound 4 shows the near regular octahedron. 2. Three new compounds on the basis of 3, 3', 4, 4'-azobenzenetetracarboxylic acid (H₄ABTC) and coligands of different configurations have been room temperature synthesized and structurally characterized three 3-D frameworks constructed by transition metals: [CuCl(phen)₂(ABTC)]·(C₂H₃O₂)·2H₂O 5 [Mn₂(bpy)₂(ABTC)(H₂O)₃]·2H₂O 6 [Mn₂(phen)₄(ABTC)]·2(C₇H₅O₃)·4H₂O 7Compounds 5-7 have two-dimensional and three-dimensional structures that are only constructed by ABTC and transition metals. Compounds 5 exhibit a near regular trigonal bipyramid [Cu(phen)2Cl]+ type and two types of 3-D channels. Compounds 6 is also show 3-D structures when linear ligand 4, 4'-bpy is introduced. The polymer is that one distinct helical chains running along the crystallographic a axis in the crystal. Compounds 7 contain crystallographically independent anionic and cationic polymeric chains.