8-Hydroxyquinolinate-Based Crystalline Materials:Synthesis,Characterization And Luminescence Properties

Due to its distinctive applications in electroluminescent devices and optical sensors,8-hydroxyquinoline-based metal-organic complexes have attracted increasing attention.Herein,three ligands based on 8-hydroxyquinoline skeletons with diverse structures and functions were synthesized through chemical modification.Based on the principles of coordination and supramolecular chemistry,a variety of8-hydroxyquinoline-based novel functional materials are hereby established via solvothermal method.These as-synthesized compounds are characterized by single-crystal X-ray diffraction,elemental analysis and so on.Additionally,their potential applications in fluorescence and cell imaging properties are also explored.This thesis is divided into the following four chapters.In Chapter 1,we summarized the structural features of 8-hydroxyquinoline and recent development of related functional materials.Additionally,an overview of the thesis topic and progress was also presented.In Chapter 2,a bis-8-hydroxyquinoline ligand H₂L₁ was synthesized in two steps.Three functional complexes with novel structures were prepared by the self-assembly of the Al(III),Ga(III)and In(III)ions with the ligand,respectively.The compounds exhibit an unprecedented structural diversification,and fabricate two tetranuclear and one pentanuclear building units in response to different central metal.The properties of these in solution were investigated by a variety of techniques,including ¹H NMR,UV-vis spectroscopy,photoluminescence,two-photon absorption and cell imaging.Moreover,distinct fluorescence properties(emission wavelength,lifetime and quantum yield)of the three complexes were observed in the solid state because of their different core structures and supramolecular structures.In Chapter 3,another bis-8-hydroxyquinoline ligand H₂L₁ which was modified by a flexible chain was synthesized in six steps.Three functional complexes with novel structures were prepared by the self-assembly of the Al(III),Ga(III)and In(III)ions with the ligand,respectively.The compounds were characterized by single-crystal X-ray diffraction,¹H NMR and so on.The results indicated that it exhibits an unprecedented structural diversification,and fabricate two tetranuclear and one octanuclear building units.The compounds exhibited different fluorescence emissions and lifetimes upon excitation due to its different core structures and supramolecular structures both in the solid state and solution.In Chapter 4,in the bis-8-hydroxyquinoline ligand H₂L₁ and Zn(II)salt reaction system,by adding different guest molecules(methyl viologen or rhodamine B),three compounds with different structures were obtained.Single-crystal X-ray diffraction analysis showed that these complexes exhibit a structural diversification due to the distinctive guest molecules and reaction temperature.Using solvothermal method,a novel trinuclear complex was fabricated by an assembly of Zn Cl₂ salt with an8-hydroxyquinolinate ligand HL₃.The complex was characterized by elemental analysis,IR spectroscopy,powder and single crystal X-ray diffraction.Besides,the luminescent properties of the four compounds were investigated in the solid state.