Synthesis, Structure And Property Of Supramolecular Compound Constructed From Transition Metals And Azobenzenetetracarboxylic Acid

In recent years, the rational design and synthesis of novel metal-organic coordination polymers based on carboxylate ligand have attracted considerable attention. Carboxylate compounds have a good many coordination modes, and benzoate primarily has five coordination modes, such as: 1) unidentate, 2) chelating bidentate, 3) bidentate, 4) bridging unidentate, 5) chelating/bridging bidentate. The supramolecular complexes have interesting topological structure as well as potential applications as catalysis, smart opto-electronic, medicine, magnetic and porous materials.Making use of ligands and complexation ions with particular conformation can gain supramolecular complexes of anticipative structure and properties through self-assemble process. However, there are many factors affecting molecular self-assembly, such as the structure of ligands, complexation construction of mental ions, solution, drogen bond and the interaction ofÏ€-Ï€. Therefore, the ligand is the most important factor. In this research, four coordination compounds have been designed and synthesized, with all of them studied systematically by Elemental Analysis and single crystal X-ray diffraction. Their crystal structures and spectral properties were characterized:1. Two 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: [Mn₂(abtc)(phen)(H₂O)₅]·6H₂O 1 [Mn₂(abtc)(phen)(H₂O)₅]·8H₂O 2Compounds 1 and 2 all have three-dimensional structures that are constructed by ABTC,phen and transition metals. Compound 1 exhibits anon- interpenetrating 1D ladders motif constructed from [Mn(abtc)]2- units and the pair of [Mn(phen)]2+ ligands attached above and below 1D ladders to furnish a 2D layers. Subtle combination ofÏ€-Ï€stacking and hydrogen-bonding interactions serves to connect the 2D coordination layers to a 3D open framework. The structure of the compound 2 is an assembling of zigzag chains. The polymer exhibit interesting three-dimensional networks assembled from two-dimensional architecture of possesses 1-D channels.2. Two 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 and another 3-D frameworks constructed by transition metals: [Cd₂(abtc)(H₂O)₈]·4H₂O 3 [Mn₂(abtc)(H₂O)₁₀]·4H₂O 4Compounds 3 and 4 have three-dimensional and two-dimensional structures that are only constructed by ABTC and transition metals. Compound 3 shows that the structure is one-dimensional polymeric chains of ABTC and Cd and exhibits an unusual 3-D supramolecular framework structure with one-dimensional channels formed via extensive hydrogen bonding interactions. Compound 4 shows that the structure is one-dimensional zigzag chains of ABTC and Cd. with hydrogen-bonding interactions and exhibits an 2-D supramolecular framework structure with one-dimensional chains formed via extensive hydrogen bonding interactions.