Synthesis And Fluorescence Properties Of Coordination Polymers Based On Tetraphenylethene-Containing Ligands

Coordination polymers(CPs)are the promising light capture platform,which has potential application prospects in the fields of luminescent materials,fluorescence sensing and biomedicine.Tetraphenylethene(TPE)is a typical aggregation-induced emission(AIE)chromophore.The construction of CPs with TPE derivative ligands obtained by subsequent modification has been a field that researchers have paid more attention in recent years.Matrix coordination-induced emission(MCIE)and AIE complement each other so that the corresponding CPs show fluorescence emission in both the aggregated state and dilute solution.In this thesis,two TPE-based ligands modified with different functional groups have been synthesized.Nine coordination compounds with novel structures have been synthesized by conventional synthetic methods with two different kinds of metal centers,and their properties such as photoluminescence,piezochromism and fluorescence sensing were examined.The content of this dissertation includes the following two parts:1.With TPE unit as the core,four pyrazole groups were modified to give 1,1,2,2-tetrakis(4-(pyrazole-1-yl)phenyl)ethene(L¹).This ligand can effectively"turn on"fluorescence when it combines with Ag⁺ions in a dilute solution.Compared with PF₆^-anion,CF₃SO₃^-anion can further induce the aggregation of silver complexes and enhance the AIE effect.On this basis,we successfully synthesized multi-nuclear silver complexes(1-3)and coordination polymers(4-7),which exhibit excellent solid-state fluorescence properties.As zero-dimensional complexes,1 and 3 have excellent piezochromic properties with color change from blue to green when ground.Furthermore,structural changes of 1 and 3 to the corresponding three-dimensional frameworks 4 and 5 occur upon immersing in ethanol.In addition,1 can act as a potential fluorescence probe for sensing nitrile compounds.2.With the TPE unit as the core,four imidazole groups were modified to produce1,1,2,2-tetrakis(4-(imidazol-1-yl)phenyl)ethene(L²),and two new cadmium(II)luminescent CPs,namely[Cd(L²)Cl₂](8)and[Cd(L²)(DMA)(H₂O](Cl O₄)₂(9)were successfully synthesized under hydrothermal conditions.Single crystal XRD shows that 8 and 9 have different two-dimensional network structures.Both 8 and 9 show piezochromic properties,the fluorescence color changes from blue to blue-green before and after grinding,and CP 8 exhibiting reversible mechanochromic luminescence with color changes and self-repairing behavior by grinding and soaking in DMF under UV irradiation.Furthermore,8 can act as potential fluorescence materials for sensing Fe(III)ion.