Synthesis, Characterization And Properties Of Pyridine-carboxylic Acid Coordination Polymers

The synthesis of coordination polymers with structural diversities and excellent properties as well as futher application investigation based on them is a research frontier of supramolecular chemistry and inorganic chemistry. The prospect of tuning the properties of MOFs through a systematic change of organic ligands provides an impect for futher research on metal-organic supramolecular architectures. Among various organic ligands, polycarboxylic compounds bearing multiple moieties, a variety of connection modes with metal centers, have been extensively used as multifunctional materials due to several arms of the V-ligand can be twisted around the center to meet the needs of coordination, which may be obtained different from the rigid and flexible ligands, and their extension ability both in covalent bonding and supramolecular interactions such as H-bonding and aromatic stacking. Such coordination polymers have profound applications in molecular recognition, materials, self-assembly and so on.In this paper, reaction of 4,4’-(hexafluoroisopropylidene) bis (benzoic acid) or 4,4’-Oxybis(benzoic acid) and a series of N-donor auxiliary ligands with transition metal ions, yielding new coordination polymers. Their crystal structures and properties have been characterized. Main contents and results are as follows:1. Assembly of 4,4’-(hexafluoroisopropylidene) bis (benzoic acid) with Cd(II)/Zn(II) in the presence of 1,3-di(pyridineyl)benzene leads to two different metal-organic 3D framework. [Cd2(dpb)(H2hfipbb)2]n(1) and [Zn(dpb)(H2hfipbb)]n(2), which complex 1 posses two types of helical chains [Cd(COO)]n, and another one displays a 4-fold interpenetrated 3D framework, constructed by left-[Zn(dpb)]n helical chain with [Zn(hflpbb)]n zigzag chain. These unique structures were studied by single-crystal X-ray and other spectroscopy techniques. In addition, the luminescent, fluorescence lifetime and second harmonic generation efficiency properties in the solid state have been studied. The resulting complexes have good thermal stability and fluorescence properties, and can be used as potential fluorescent materials.2. A new kind of Nanocoordination polymer materials was synthesis by self-assembly through 4,4’-Oxybis(benzoic acid) or 2,5-Pyridinedicarboxylic acid with Cu(II) at various conditions. The asobtained products were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR), and elemental analysis. Crystalline CuO particles were formed from the calcination of Cu-CPPs, exhibiting a high catalytic activity for the reduction of 4-nitrophenol in excess NaBH4 solution. The results show that the different conditions can be obtained with different morphologies of the complexes, and the resulting complexes can be used as good catalysts after calcination of the oxides.