Design,Synthesis And Applications Of Photofunctional Molecules Capable Of Capturing And Releasing Singlet Oxygen

Polycyclic aromatic hydrocarbons with photothermal response characteristics have been widely used in biomedical and optoelectronic fields.Polycyclic aromatic hydrocarbons are able to trap singlet oxygen to form endoperoxides?EPO?,which can release singlet oxygen upon heating.Under the external stimulation of light and heat,the structure and properties of molecules will be changed significantly,which has become a research hotspot in recent years.Among them,therefore,polycyclic aromatic hydrocarbons can be used as a kind of stable organic singlet oxygen carrier.1,4-Dimethylnaphthalene is one of the best singlet oxygen carrier because of its advantages of easy structure modification,strong singlet oxygen capture ability and good solubility.In this thesis,we have introduced 1,4-dimethylnaphthalene as singlet oxygen carrier into phosphorescence iridium?III?complexes and azafluoroboron dipyrrole dyes?aza-BODIPY?,and prepared new molecules Ir1-SO and aza-BODIPY1.Their singlet oxygen capture and release capabilities have been investigated.Finally,we have applied them in information encryption and photodynamic therapy.The main research contents are shown as follows:?1?We have designed and synthesized a class of phosphorescent iridium?III?complexes Ir1,Ir2 and Ir3 containing different main ligands.Under the illumination,iridium?III?complex Ir1 with1,4-dimethylnaphthalene unit can capture singlet oxygen to form endoperoxide Ir1-SO.Under normal oxygen conditions,Ir1 exhibits yellow emission?562 nm?.Ir1 captures singlet oxygen to form Ir1-SO after illumination and the luminescence lifetime increased from 212.9 ns to 322.7 ns.After Ir1 was exposed to light at 365 nm,the molecular weight of Ir1 increased from 986?Ir1?to1049?Ir1-SO?.By heating Ir1-SO,Ir1-SO reverts to Ir1.Then,we used Ir1 solution as ink and printed it on paper covered with Ir2.Through life-time imaging,we can observe the reversible information display-erasing process,which realizes the application of information encryption of materials.?2?We have designed and prepared a class of azadipyrrole boron dyes?aza-BODIPY?containing different naphthalene units.Under 690 nm light illumination,aza-BODIPY1 containing1,4-dimethylnaphthalene unit can capture singlet oxygen to form endoperoxide aza-BODIPY1-SO.By encapsulating aza-BODIPY with DSPE-PEG₅₀₀₀,water-soluble nanoparticles?NPs1?with uniform size are prepared.Compared with the compound aza-BODIPY1,the absorption of NPs1 is red-shifted,and its photothermal effect is improved.NPs1 can capture singlet oxygen to form NPs1-SO under 690 nm light excitation,and NPs1-SO can effectively release singlet oxygen due to its photothermal effect.Photophysical properties studies have shown that NPs1 can be used as a photothermal and near-infrared imaging reagent due to its strong near-infrared absorption.Cellular reactive oxygen detection experiments show that both NPs1 and NPs1-SO can produce singlet oxygen.Cytotoxicity tests show that NPs1-SO has low dark toxicity and high phototoxicity,and can be used for photodynamic therapy to effectively kill cancer cells.