Complexes Based On 3,4 ', 5 - Azobenzene Acid Construct, Characterization And Nature Of The Study

The carboxylic acid coordination polymers have shown promised with a bright future, for it has potential applications in a variety of areas, including optical material, magnetic material, and porous material and so on. Recently, much attention has been paid to the designs, syntheses, crystal structures and properties of the carboxylic acid complexes. In this research, nine new coordination complexes have been designed and synthesized, with all of them studied systematically by elemental analysis, IR spectra and single crystal X-ray diffraction. The crystal structures, magnetism, thermal stability, gas absorption and fluorescence have also been performed and discussed. The main contents and conlusions are as follows:1. Seven complexes{[M2(ABTC)2(DMF)2(H2O)2]·DMF·H2O}n(M=Sm, Eu, Gd, Tb, Ho, Er, Yb) have been synthesized with 3,4',5-azobenzenetricarboxylic acid and lanthanide metal. The analysis of structures display that these complexes are isostructure, and two lanthanide (Ⅲ) ions are connected by six carboxylate groups to generate a [Ln2(COO)6] dinuclear group, which serves as octahedral secondary building units (SBUs) to produce a novel noninterpenerative 3D porous framework. Complex 1 exhibits high nitrogen adsorption; the magnetic measurement shows that complex 3 presents antiferromagnetic behavior.2. The complex [Cd3(ABTC)2(H2O)9·2H2O]n(8) has been synthesized with 3,4',5-azobenzenetricarboxylic acid and cadmium metal. The single crystal X-ray diffraction study reveals that the asymmetric unit links to each other to form a typical "T-shaped" molecular bilayer motif subunit, moreover, the bilayer motif subunit links to form 2D structure. The 2D adjacent bilayer subunits are further polycatenated with each other to give rise to the 3D supramolecular framework with rectangle channels along the b direction. The 3D framework with rectangle channels may absorb small molecules, such as H2O,benzene and so on, which may have potential applications in microporous material. Fluorescence experiments analysis shows that the ligand presents strong fluorescent emission band at 427nm, and comparing complex 8 wih the ligand can find the blue shift occurred.3. The 3,4',5-azobenzenetricarboxylic acid broke into 5-aminoisophthalic acid, the complex [Cd(AIP)(H2O)·2H2O]n(9) has been synthesized with 5-aminoisophthalic acid and cadmium metal. Single-crystal X-ray diffraction study displays that the 2D net exists different subrings A, B, C and D, and the{CdAIP}n layers are assembled into a 3D network via interlameller hydrogen bonding. Fluorescene experiments analysis shows that weak fluoreseence can be found near 450nm in complex 9.