Amphiphilic Dyes Containing Dynamic Covalent Bonds: Synthesis And Aggregation In Water

Pyrene and its derivatives are widely used in the field of dyes and optoelectronics due to their excellent optical properties and excellent chemical,light,and thermal stability.In addition,because of its flat polycyclic aromatic structure,it has a strong π-π stacking tendency in solution,and is often used as a valuable building block for various supramolecular assemblies.Supramolecular self-assembly has become a powerful tool of constructing complex chemistry,among the various components of supramolecular self-assembly,amphiphilic molecules containing both hydrophilic and hydrophobic parts have become one of the most powerful building blocks.In this thesis,pyrene-modified maleimide dyes were synthesized,and amphiphilic dyes were further obtained through clean and effective dynamic Diels-Alder reversible reactions,and they were characterized by NMR spectrum,infrared spectroscopy,mass spectrometry,and elemental analysis.These new dyes exhibit surprising optical properties,photoelectric properties,and supramolecular donor/acceptor dipole interactions,which have been confirmed by ultraviolet-visible absorption spectroscopy,fluorescence spectroscopy,frontier molecular orbital calculations,and electrochemical cyclic voltammetry.Nonfluorescent maleimide dyes and their fluorescent derivatives can be formed and cleaved reversibly by the dynamic Diels-Alder reaction between furan/maleimide.It was observed that the reversible reaction is accompanied by an interestingly switchable fluorescence on/off behavior.X-ray single crystal diffraction shows that the distance between the pyrene group and maleimide is 3.38 (?),which is due to the combination of supramolecular donor/acceptor dipole interaction and π-π stacking interaction.Generally,π-π stacking distance(3.54 (?))has stronger interaction.Dynamic light scattering,scanning electron microscopy and transmission electron microscopy showed that the amphiphilic dye derivatives self-assemble into blue fluorescent hollow vesicles in water,with an average diameter of 115-120 nm.