Florescent Supramolecular Polymers Constructed By Metal Coordination And Macrocyclic Host-guest Reaction

Supramolecular polymers,as the combination of supramolecular chemistry and polymer science,are polymers with specifically structures and properties,which are formed by small molecular monomers through weak noncovalent interactions.Compared with traditional polymers,supramolecular polymers not only possess many characteristics of traditional polymers,but also possess various unique properties,such as stimulus-responsiveness and self-healing.With the rapid development of supramolecular chemistry,supramolecular polymers with various topological structures and functional characteristics have been fabricated.Metal coordination interaction and host-guest recognition are two important driving forces of the construction of supramolecular polymers.The main contents of the paper are as follows:（1）A novel fluorescent supramolecular crosslinked alternative polymer with the reversible fluorescence switching was constructed by self-assembly of pillararene and crown ether-based host-guest reactions.Firstly,three monomers M4,N4 and AE were designed and synthesized.The monomer M4 was composed of four benzo-21-crown-7（B21C7）moieties were bridged by tetraphenylethene,the monomer N4 consists of four pillar[5]arene groups were bridged by tetraphenylethene,the monomer AE contained a dialkylammonium salt group and a neutral guest molecule（TAPN）.The three monomers M4,N4 and AE could self-sorting assemble into supramolecular crosslinked alternative polymer in chloroform and acetone（v/v=2/1）.The gels could be obtained by the supramolecular crosslinked alternative polymer at high concentrations.Due to the dynamic reversibility of noncovalent interactions,reversible gel-sol transition of supramolecular polymer gels could be achieved by the addition or removal of K⁺.Due to the aggregation-induced emission mechanism of tetraphenylethene,the polymerization of supramolecular crosslinked alternate polymer could induce the fluorescence emission enhancement of the supramolecular crosslinked alternative polymer,and the reversible"on-off"switchable fluorescence could be realized by the disassembly-reassembly of the supramolecular crosslinked alternative polymer.（2）A novel fluorescent supramolecular hyperbranched polymer was fabricated through the orthogonal self-assembly of pillar[5]arene-based host-guest interaction and metal coordination interaction.Firstly,three monomers M1,M2 and H1 were designed and synthesized.M1 was composed of three terpyridine groups;M2 contained a 9-anthracenyl-substituted terpyridine（tay）group and a neutral guest;H1 contained three pillar[5]arene groups.A supramolecular hyperbranched polymer could be formed by the orthogonal self-assembly of the three monomers M1,M2,and H1 with Zn（OTf）₂ in chloroform and methanol（v/v=3/1）.The orthogonal self-assembly behavior of the three monomers were studied by proton nuclear magnetic resonance,（homonuclear chemical shift）correlation spectroscopy,nuclear overhauser effect spectroscopy,and UV-Vis absorption spectroscopy.The result revealed the successful construction of supramolecular hyperbranched polymer.The obtained supramolecular hyperbranched polymer exhibits the stimuli-responsive behavior of butanedinitrile,and the fluorescent properties of the supramolecular hyperbranched polymer are concentration-dependent,the fluorescent emission intensity gradually decreases with the increasement of monomer concentration.