| Metal-organic frameworks?MOFs?with adjustable pore size,designable structure and controllable function,have potential applications in fluorescent sensors,gas adsorption,separation and conversion,catalysis and other fields.Organic ligands acting as the linkers of the frameworks,can be a key factor to determine the properties of MOFs.In this thesis,two kinds of flexible ligands 1,1'-di?4-carbonylphenyl?-2,2'-biimidazoline?H2dcba?and 2,5-bis-??pyridin-2-ylmethyl?thio?-1,3,4-thiadiazole?bptz?were used to construct MOFs,and twenty novel transition MOFs were successfully synthesized under hydrothermal?solvothermal?conditions.The coordination modes,configuration changes of the ligands,and properties of the complexes have been investigated.The thesis is divided into four chapters:The first chapter is the introduction,which summarizes the development of coordination compounds,the application of functional metal-organic framework of N-containing aromatic carboxylate,as well as the basis of the research,research methods and the main achievements in this thesis.In the second chapter,based on H2dcba ligand containing two carboxylate and two azole groups,twelve complexes[Mn?dcba?]·xDMF?1?,[Co?dcba?]·x DMF?2?,[Co?dcba???2-H2O??CH3OH?]·CH3OH?3?,[Zn?dcba?]·x DMF?4?,[Zn?dcba?]·?CH3CN?2·?H2O?3?5?,[Cd?dcba??DMA?]·DMA?6?,[Cd?dcba??H2O?]?7?,[Cd4Cl2?dcba?3?H2O?2]·?CH3CN?·?DMF?2·?H2O??8?,[Mn1.5??2-Cl??dcba??DMF?2]·DMF?9?,[Ni?dcba??H2O?2]?10?,[Cu?dcba??H2O?]·H2O?11?,[Cu?SO4??H2dcba??H2O?2]·H2O?12?were successfully synthesized by adjusting the reaction conditions.Complexes 1-8 are 3D frameworks with different porous structures.Complexes 9-12 are 2D or zero 0D complexes,which further form to 3D supramolecular structure by?-?stacking or hydrogen bonding.In complexes 1-12,due to the coordination interactions of different metal ions,the ligands exhibit various coordination modes such as?1-??3-??4-??5-and?6-briding,with dihedral angle range between the two imidazolyl groups 9.3°-77.7°,and the dihedral angle range between imidazolyl group and benzene ring 33.3°-63.0°,respectively.In the third chapter,based on flexible ligand bptz containing N/S atom,eight complexes[Zn?bptz?0.5?bdc?]·H2O?13?,[Co?bptz?0.5?bdc?]·H2O?14?,[Cd1.5?bptz??bdc?1.5?DMF?]?15?,[Zn??2-OH??bptz?0.5?tdc?]·H2O?16?,[Cd?bptz??Htdc?]?17?,[Cd2?bptz?2?H2tba?2?H2O?]?18?,[Zn?bptz??bpta?]·H2O?19?were successfully synthesized by adjusting the reaction conditions and introducing the second ligand.Complexes 13-15,17 are 3D coordination frameworks with different porous structures with bridging bptz ligands,which make the framework more flexible.Complexes 16,18,19 are 2D or 1D complexes which further form to 3D supramolecular structures by?-?stacking or hydrogen bonding.In complexes 13-19,bptz ligands adapt two coordination modes:bridging and chelating.With the coordination of different metal ions and auxiliary ligands,the distances between two pyridyl groups in bptz ligands are different,resulting in different coordination configurations.In the forth chapter,the purity,thermal stability,fluorescence properties and molecular sensing properties of the synthesized complexes were investigated.The fluorescence properties of complexes 4,6,7 and 9 can be attributed to?*?n or?*??transitions of the ligand H2dcba.Complexes 4 and 6 are porous 3D coordination framework,and have good stability in common solvents such as water,methanol,ethanol,DMF,DMA and so on.Further studies show that both complexes 4 and 6 can detect acetone solvent molecules by fluorescence quenching effect,and have good anti-interference and recyclability in the mixed systems.Simultaneously,the complex 4 also has the ability to detect Fe3+effectively,showing its potential application as ion sensor. |
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