Controllable Self-assembly And Properties Of Supramolecular Aggregates Containing Cavity Ligands

Supramolecular materials are complex and orderly molecular aggregates with specific functions,which are bonded by weak interaction of non-covalent bonds,while polymers are materials with diverse structure and performance formed by covalent bonds.Supramolecular synthesis and host-guest interactions are introduced into the polymers,and noncovalent interactions are used as the key driving force to synthesize supramolecular polymers,so that it has both strong mechanical properties of covalent bonds and dynamic properties of non-covalent interaction.Organometallic coordination polymers are considered as ideal candidates for constructing functional and stimuli-responsive materials.Among them,those based on cuprous-iodide nanoclusters have,in particular,captured the attention of researchers due to their highly emissive nature and outstanding luminescence properties.However,it is difficult to realize the precise and controllable synthesis of supramolecular cuprous-iodide nanoclusters due to the diverse coordination numbers of copper（I）metal centers in the structure,the changeable coordination modes of iodine ions bridging,the randomness of assembly and the poor chemical stability of cuprous-iodide cluster nuclei,which has become an urgent scientific problem and challenge in this field.To this end,two organic ligands with C₃ symmetry were designed to react with Cuprous iodide in this paper,and two distinct[（Cu₃I₃）L]supramolecular clusters were accurately constructed by means of conformational adaptive and host-guest encapsulation self-assembly strategies.The precise self-assembly and structure regulation of highly stable（Cu I）_x supramolecular clusters in constrained space are realized,opening up a wide range of possibilities and opportunities for controlled self-assembly and precise synthesis of supramolecular clusters with[Cu₃I₃]structure.In chapter Ⅰ,the fundamental ideas and specialized vocabulary of supramolecular chemistry are explained,its historical context and evolution are expounded.The research progress and assembly strategy of cuprous-iodide supramolecular clusters are emphatically introduced,and the assembly strategy and application performance of[Cu₃I₃]clusters are summarized and analyzed.After that,we provide an overview of CuAAC-catalyzed click reactions,covering their definition,advantages and catalytic mechanism.Finally,this paper’s organic ligand（8-hydroxyquinoline）is briefly discussed.In chapter Ⅱ,a flexible ligand T of quinoline derivative with C₃ symmetry is synthesized,and its fluorescence properties are unexpectedly found.Despite the fact that metal complexes containing 8-hydroxyquinoline and its derivatives are luminous materials with wide applications,the ligand itself,8-hydroxyquinoline,is a fairly weak fluorophore in most of the media.The 8-hydroxyquinoline derivative ligand designed and synthesized in this paper has a reversible molecular configuration and produces fluorescent luminescence changes under the induction of guest molecules.This section focuses on the fluorescence sensing function of T.It is found that dichromate ions have fluorescence quenching effect on T,and the detection limit is 0.255 mM;However,H₂SO₄ and SO₂ can enhance the fluorescence of T,and the detection limit of H₂SO₄ is 0.098μM,while that of SO₂ is 5.438μM.The sensing mechanism of two completely different fluorescence phenomena is explored respectively.In chapter Ⅲ,two semi-rigid quinoline ligands,L¹ and L²,are designed to react with cuprous iodide respectively.In C₃ symmetric ligand cavities,two distinct supramolecular clusters of the[（Cu₃I₃）L]-type are constructed by using a conformational adaptation and host-guest inclusion self-assembly strategies.Functional organic ligands spontaneously fold into trans-configuration（bowl-shaped）during the self-assembly process,and in-situ self-assembly occurs through Cu-N and Cu-O coordination connections to create the cluster core of Cu₃I₃.Furthermore,during WLED irradiation at room temperature,two well-defined[（Cu₃I₃）L]-type supramolecular clusters demonstrate good photocatalytic activity for the CuAAC process in water/acetonitrile solution,and their photocatalytic yield reach as high as 90%.On this basis,this chapter systematically analyzes and explores its photocatalytic mechanism and possible paths,and it concludes that the energy difference between energy levels and the quantity of exposed metal atoms on cluster surfaces impact the catalytic activity.This effective synthesis strategy provides several possibilities and techniques for cuprous iodide to coordinate with functional ligands to form controlled self-assembly of multinuclear supramolecular clusters containing[Cu₃I₃]central units.