Self-assembly And Luminescence Properties Of Zn(?)Schiff Base Complexes Based On 8-hydroxyquinoline

8-Hydroxyquinoline and their derivatives feature excellent luminescence properties and is capable of forming stable complex through chelating coordination of the oxygen and nitrogen atoms with metal ions.Incorporating 8-hydroxyquinoline derivatives with dynamic imide bond into a Schiff base system,metal complexes with special luminescence property and specific geometry can be designed and synthesized through the self-assembly processes using metal ions as the templates.In this dissertation,a series of self-assembled Schiff base Zn?II?complexes with various structural configurations were well isolated from the sell-assembly of 8-hydroxyquinoline-functionalized aldehyde ligands,aromatic amine ligands,and Zn?II?.Their photophysical properties and structural regulation processes were systemic investigated.The results of this dissertation are shown below.1.Quinoline-based Zn???Schiff base complexes exhibit aggregation-induced emission and reversible mechanochromism characteristicsComplexes 1,2 and 3 were obtained by self-assemble reaction of8-hydroxyquinoline-based aldehyde,aniline,and Zn?II?in room temperature.In the solution of Et₂O/CH₃CN mixture with different Et₂O fraction,fluorescence enhancement were observed upon increasing the Et₂O proportion,indicating the typical aggregation-induced emission enhancement property.Moreover,they show revesible mechanochromic luminescence behavior between dark and bright states during the grinding-fuming cycles,due to the modulation of morphologies between amorphous and crystalline states.2.Bi-/tri-nuclear zinc Schiff base complexes based on di-aldehyde quinoline ligands connecting by flexible carbon-chainBinuclear Zn???Schiff base complex 4 with yellow-orange fluorescence was assembled by the reaction of 2-aldehyde-8-hydroxyquinoline derivatives,aniline and Zn???trifluoromethane sulfonate.The binuclear Zn???complex was stabilized at room temperature,however,converted into tri-nuclear complex after heated to 60°C.3.Cyclic zinc Schiff base complexes based on rigid aromatic di-amine ligandsCyclic Zn???Schiff base complexes 6 and 7 were obtained from2-aldehyde-8-hydroxyquinoline derivative,rigid aromatic di-amine ligands and Zn???trifluoromethane sulfonate at room temperature.These cyclic complexes were carefully characterized by ¹H NMR,2D DOSY,UV and IR.