Design,Synthesis And Properties Of MOF Materials Based On Semi-rigid Polycarboxylate Ligands

The research work of this paper mainly includes three parts.Firstly,three kinds of organic ligands,H₃L1,H₄L2 and DPD have been designed and synthesized.Secondly,three-dimensional thin crystal MOF 1 with rod-shaped secondary building units have been self-assembled by H₃L1 and Cd²⁺,the luminescent and gas adsorption properties were also tested.Thirdly,three-dimensional purple black crystal MOF 2 with five core cobalt clusters have been self-assembled by ligands H₄L2 and DPD with Co²⁺,magnetic test shows that there is strong ferromagnetic interaction in the molecule,and the dark yellow crystal MOF 3 with binuclear cobalt clusters and the light yellow crystal MOF 4 with single-core cobalt are obtained by double stimulation of temperature and solvent.1.Three kinds of organic ligands were designed and synthesized:semi-rigid tricarboxylic ligand 4',4'',4'''-?nitrilotris?methylene??tris?[1,1'-biphenyl]-4-carboxylic acid??H₃L1?,semi-rigid tetracarboxylic ligand 5-?bis?4-carboxybenzyl?amino?isophthalic acid?H₄L2?and rigid ligand 4,4'-?2,5-diethoxy-1,4-phenylene?dipyridine?DPD?.Three ligands were all characterized.2.A novel single crystal material?MOF 1?was prepared by solvothermal self-assembly of ligand H₃L1 and Cd²⁺.The result of single crystal diffraction shows that rod SBU exists in the MOF framework.The crystal structure was characterized by powder diffraction,thermogravimetry and infrared,and its luminescent properties were tested.The results show that the maximum emission wavelength was 387.6 nm under 313 nm excitation.In addition,the gas adsorption test shows that MOF 1 has better gas adsorption performance.3.A purple black three-dimensional complex MOF 2 with five core cobalt clusters was constructed by solvothermal reaction of semi-rigid tetracarboxylic acid H₄L2 and flexible branched rigid ligand DPD with Co²⁺.The crystal structure was characterized by powder diffraction,thermogravimetry and infrared,and its magnetic property was measured.Finally,MOF 3 was obtained at DMA/H₂O?2 ml/2 ml?and 95°C respectively,and MOF 4 was obtained at DMA/H₂O?1 ml/2 ml?and 90°C respectively.Under the double stimulation of temperature and solvent,the transformation of single crystal structure is realized.