Supramolecular Self-Assemblies Based On Donor–Acceptor(D-A)Structures And Their Photolysis

Photolyzable polymers are widely used in materials science,environmental science,biomedicine and so on.Supramolecular self-assembly,as an advanced approach to the fabrication of functional polymers,shows well-organized structure,controllable assembly behavior,and great responsiveness upon external stimulus.Therefore,controlled photodecomposition within supramolecular and polymeric system has been increasingly studied for the construction of novel photolyzable material.However,such systems are generally based on limited monomers and response modes.It is important to develop new structures,and even strategies.,some potential photoactive molecules are designed and synthetized.After assembled into supramolecular aggregates,their photolytic properties are activated,giving photodegradable materials.Our work provides a new strategy for the preparation of photodegradable materials.The major contents of this thesis are as follows:1.Photolysis of polymeric self-assembly controlled by donor–acceptor(D-A)interaction.Two photodegradable supramolecular polymers were constructed by the combination of 9,10-dialkoxyanthracene derivatives and cucurbit[8]uril(CB[8]).Due to the presence of D-A interaction,the guest molecule is light-stable.After the formation of the supramolecular polymer,intramolecular D-A interaction is inhibited,thereby endowing the guest molecule with good photodegradability and the photodegradability polymer was prepared.In conclusion,we controlled the molecular D-A interaction through the supramolecular self-assembly behavior and developed a method for preparing photoactive polymers with photo-inert monomers,which provided new ideas for the design of photodegradable polymers.2.Amphiphilic assemblies based on hemicyanine and its aggregation-enhanced photodecomposition under visible light.A hemicyanine pigment with strong intramolecular D-A structure was designed and synthesized,which formed supramolecular aggregates in aqueous solution.Due to the strong D-A interaction,hemicyanine dyes show intense absorption in the visible region.However,because of the conjugated D-A structure and the intramolecular twisted charge transfer effect,such dyes are generally light-inert.Herein,the amphiphilic hemicyanine dye hardly exhibits photoactivity in the monomer state,but shows photodecomposition after aggregation.Moreover,the photoactivity can be greatly enhanced by adjusting the mode of aggregation.Therefore,we have successfully mediated the photolysis of hemicyanine dyes through aggregation,and fabricated a visible-light-responsive amphiphilic assembly with good potential application in photodynamic therapy.