Based On Rational Selection Of Building Units To Construct Coordination Polymers: Syntheses, Structures And Properties

Mental-organic coordination polymers which are built from multidentate organic ligands and metal ions or in situ generated metal ion clusters through coordination bonds have attracted much attention over the past three decades. In recent years, the researches of coordination polymers, especially porous coordination polymers/ metal–organic frameworks(MOFs), have made rapid developments due to their intriguing variety of molecular architectures and potential applications such as gas storage and separation, catalysis, drug delivery, chemical sensing and luminescence, magnetism and so on. For the construction of coordination polymers, the nature of the metal centers and organic ligands are the crucial components. In this thesis, we choose a kind of bifunctional ligands with both m-benzenedicarboxylate acid and tetrazole units to construct new frameworks with different functions. The research work about this topic can be divided into the following aspects:1. Seven transition coordination polymers have been synthesized by involving bifunctional ligands 5-tetrazolylisophthalic acid(H3TZI) and 5-(4-(1H-tetrazolyl)phen)isophthalic acid(H3TZPI). Three of them are construct by Zn2+ and Cd2+ centers with H3 TZI, [Zn2(TZI)(μ3-OH)(H2O)2]·(CH3)2NH(1), [Cd5(TZI)3(μ3-OH)(H2O)7]·x H2O(2), and [Cd(TZI)]·(CH3)2NH2+·H2O(3). H3 TZI performs outstanding flexibility which made these structures show very different nets. 1 features 3D frameworks including 1D rectangular channels with dimensions of 6.5 × 3.2 ?2 and it performs 5-commected(46?64) topology, and 2 performs a 3D supermolecular structure by strong H-bonds containing 2D sandwich-like tri-layer, 3 exhibits 3D with 4-connected(42?63?8) topology. Furthermore, the fluorescence properties of the three MOFs were measured at room temperature. Photoluminescence investigations reveal that 1, 2 and 3 display strong main emission spectra peaks at 410, 437 and 415 nm, respectively.The other four structures are obtained by H3 TZPI coordinating with Zn2+, Cu2+ and Cd2+ centers, [Zn2(TZPI)(μ3-OH)(H2O)2]·2H2O(4), [Cu(HTZPI)(μ2-H2O)0.5(H2O)1.5]·5(H2O)(5), [Cd(H2TZPI)2(H2O)2]·2H2O(6) and [Cd2(TZPI)(μ3-OH)(H2O)2]·H2O·DMF(7). 4 exhibits fascinating three-dimensional structures containing rectangular channels with dimensions of 6.5 × 3.0 ?2 and it performs 5-commected(46?64) topology, 5 displays 3D supramolecular structures with 12.5 × 14.6 ?2 hexagonal channels. Complex 6 shows 1D chain structure and further form to 3D supramolecular framework by noncovalent interactions(C-H···O, O-H···N, and π···π interactions), whereas complex 7 exhibits fascinating 3D frameworks with 5-commected(44?66) topology. The observed structural diversity in these frameworks is due to the outstanding coordination modes and configurations of the H3 TZPI ligand. The photoluminescence of 4, 6, 7 and the magnetic properties of 5 are measured at room temperature. Photoluminescence investigations reveal that complex 4, 6 and 7 display strong main emission spectra peaks at 388, 363 and 423 nm, respectively. Complex 5 is found to exhibit an antiferromagnetic interaction between Cu2+ ions.2. We changes rare earth metal as metal centers to coordinated with H3 TZI and H3 TZPI, three complexes are found, [Eu(TZI)(H2O)5]·2H2O(8), [Dy(TZI)(H2O)4]·4H2O(9-Dy), [Tb(TZI)(H2O)4]·5H2O(9-Tb) and [La(HTZPI)(HC2O4)(H2O)3]·H2C2O4(10). X-ray crystallography reveals that complexs 8 and 9 are similar 1D double-chain structures, complex 10 shows 2D layer framework. It is notable that the tetrazole unit is free in these structures. We also research the fluorescence properties of the three complexes.In addition, porous coordination polymers have attracted considerable attention in recent years because of their potential applications in many areas including gas storage, separation, and catalysis. Undoubtedly, the most desired property in order to allow the accommodation of chemical entities such as, for instance, in the storage of energy-relevant gases(e.g., H2 and CH4), capture of CO2, removal of toxic gas molecules and inclusion of biologically active species. Bearing these above, we carried out our research work as follows:3. We use 2-Methylterephthalic acid(2-Me BDC) together with different N-donor ligands to synthesise two porous coordination polymers materials, [Zn2(2-Me BDC)2(TED)]·x G(11) and [Zn2(2-Me BDC)2(bipy)]·x G(12). Complex 11 exhibits 3D open frameworks, complex 12 performs flexible porous. We study their distinct porous properties and we found that 11 shows higher BET(1350m2g-1) and satisfying adsorption capability for H2, CO2 and CH4, and for 12, it performs obviously breathing effect for CO2 adsorption at 1 atm, 195 k, we also research its reversibility of the pore. Moreover, we try to explore the effects of methyl for the two different pores.