Syntheses,Crystal Structures And Properties Of Ag(Ⅰ)/Pb(Ⅱ)/Ln(Ⅲ)-based Complexes Constructed By 1,2,3,5-benzenetetracarboxylic Acid

As the rapid development of hybrid composites,metal-organic coordination polymers,which combined the peculiarity of inorganic metal ions and organic ligands,will have an immeasurable potential for application in more fields.Aromatic carboxylic acids have been used in the construction of novel structure and functional coordination polymers owing to flexible coordination modes,as well as controlability of structure.In recent years,the design,syntheses,crystal structures and properties of coordination polymers have attracted considerable attention.Ag（I）,Pb（II）and Ln（III）,which have the 4d¹⁰,6s² and 4f^0-14 outer electron configuration,are chosen to be central metal in this paper.1,2,3,5-benzenetetracarboxylic acid（H₄btec）is chosen to be organic ligand and twenty-two metal-organic coordination polymers have been hydrothermally synthesized.Single crystal diffraction was used to confirm their crystal structures.X-ray powder diffraction was used to test the pure of the complexes and coordination information is verified by IR and elemental analysis.Their thermal stabilities,photoluminescence and antibacterial properties were also studied.The organization of chapters is given as follows:1.Four novel silver coordination polymers constructed from H₄btec,namely,[Ag₂（H₂btec）（H₂O）]（1）,[Ag₃（Hbtec）]（2）,[Ag₄（btec）]（3）and [Ag₃（H₂btc）₂（Hbtc）]（4）,have been synthesized with hydrothermal methods;notably,H₃btc（1,3,5-benzenetricarboxylic acid）formed via the in situ reaction of H₄btec.For the lack of coordination and lattice water molecules in complexes 2-4,nearly no weight loss being observed less than 280 °C.The results show that Ag-Ag interaction in these complexes has a significant influence on the photoluminescence properties and compound 4 exhibits strong blue photoluminescence at room temperature.Ag-based complexes are suit for further antibacterial application to Escherichia coli and Staphylococcus aureus.The diameters of inhibition zones for these compounds are ranked: 1 > 4 > 3 > 2,which is consistent with Ag⁺ ion release capacities.2.Four new lead coordination complexes with H₄btec and 1,10-phenanthroline,namely,[Pb（H₂btec）（H₂O）₂]（5）,[Pb₂（btec）]（6）,[Pb₃（μ4-O）（btec）（H₂O）₂]?H-2O（7）and [Pb（btec）_0.5（phen）]（8）,were hydrothermally synthesized.For complexes 6 and 8,nearly no weight loss being observed less than 340 °C.Pb-based complexes 5-8 exhibited excellent photoluminescence properties at room temperature.3.Fourteen rare earth coordination complexes based on H₄btec,namely,[Ln（Hbtec）（H₂O）₂]（Ln= La（9）Ce（10）Pr（11）Nd（12）Sm（13）Gd（14）Dy（15）Ho（16）Er（17）Yb（18））,[Y₃（Hbtec）₃（H₂O）₆]（19）,[Yb₂（Hbtec）₂（H₂O）₄]（20）,[Na₂Ln₂（btec）₂（H-2O）₄]·H₂O（21）and [NaPr（btec）（H₂O）₂]（22）have been prepared.Complexes 9,19 and 21 are constructed by inert ions,which have no obvious fluorescent emission.Compound 14 produce similar intense luminescence with free ligand.The intensity of Pr（III）,Yb（III）-based complexes is enhanced,while 13 and 15 exhibited excellent photoluminescence at room temperature.The antibacterial effect of the complex 21 was significantly superior to that of the free ligand and some transition metal coordination polymers.4.The researching work of this topic was summarized and the future research was also prospected.