Pyridine-2 ,5 - Dicarboxylic Acid With Lanthanide And Transition Metal (copper) Synthesis, Structure And Properties

It is still a great challenge to synthesize the specific structure complexes with the lanthanide metal with a high coordination number and flexible coordination geometry. In this thesis, the Ce3+, Pr3+ complexes and the complexes involved of heteroatomic Cu and lanthanides were constructed with rigid ligand pyridine-2,5-dicarboxylic acid (H2pyda), single crystal X-ray diffraction, solid-state fluorescence fluorimctric and thermal stability have also been performed and discussed. The following is the main contents and conclusions.1. Two complexes [(Lnpyda-LnHpyda-nH2O)-mH2O] [Ln=Ce(1), Pr(2)]had been synthesized with pyridine 2,5-dicarboxylic acid (H2pyda) and lanthanide metal cerium and praseodymium, the analysis of structure displays that two complexes are isostructure in 2D plain, in which the coordination mode of ligand is bridging-chelating, and the metal ion connected by carboxyl into a 1D helical chain.2. The heteroatomic complexes [Ln(Cupyda-H2O)n·mH2O]p-H2O [Ln= Tb(3), Eu(4), Dy(5), Ho(6), Lu(7), Pr(9)] have been synthesized when the transition metal copper has been added. The analysis of element and structure shows that, complexes 3 and 4,6 and 7 are isotructure; in these complexes, a small building unit has been formed firstly by chelation through 2-position oxygen, nitrogen atom of ligand and copper, and then the lanthanide ions connected by the remaining coordination sites.3. A heteronuclear complex of 3D framework, [(Ndpyda-3H2O)2(Cupyda)-H2O]n, has been synthesized when the transition metal copper have been added. The structural analysis indicates that, in this polymer, the ligand coordinates to Cu and Nd ions in different chelating modes, 1D chain formed by the unit of (Ndpyda-3H2O) by 5-position carboxyl oxygen atoms and a ladder chain formed by extention of (Ndpyda-3H2O) via 2-position carboxyl oxygen, Cu ions from (Cupyda) unit in this complex are connected by 5-position carboxyl oxygen in unit of (Ndpyda-3H2O) leading into a 2D framwork.4. Solid-state fluorescence experiments analysis at room temperature show that, weak fluorescence have been found near 450nm in coplexes 5,6,7,8 and 9. Compareing the complex 2 with 9 can be found the blue shift occurred when the transition metal ions of copper is added. 5. The thermal decomposition behavior of the nine complexes have been performed:lattice water and coordinated water in the complexes loss easily between 100℃and 200℃, and the polymers exist stably before the temperature 300℃except the complex 5 (280℃).