Preparation And Optical Properties Of Structurally Distorted Aza-fluoroborylpyrrol

This article briefly the design and synthesis methods of BODIPY/aza-BODIPY fluorescent dyes and their applications in photodynamic therapy and photothermal therapy are briefly described.Asymmetric aza-BODIPYs dyes containing-NMe₂ groups and twisted halogen-free aza-BODIPYs dyes bearing the with a-CH₂-X-（X=CH₂,O,S）chain.In the second chapter,a series of aza-BODIPYs with dimethylamino groups were successfully prepared by 4’-dimethylaminoacetophenone.The solid-state structure of CF₃-BDP was confirmed by X-ray crystallographic analysis,and the boron atom in the center showed a slightly distorted sp³ hybridization.The maxima absorption of aza-BODIPYs with the-NMe₂ group were found to locate in the range of 740-780 nm.Their molar extinction coefficients are high and the fluorescence quantum yields are very low.The singlet oxygen yields of CF₃-BDP was calculated to be 0.053 and slightly higher than that（Φ_Δ=0.02）of tetraphenyl aza-BODIPY.The photothermal conversion efficiencies of CF₃-BDP NPs,OMe-BDP NPs and OMe R-BDP NPs were calculated to be49%,49%and 50%,which are comparable to those（35-50.5%）of the reported aza-BODIPY-based photothermal agents（PTAs）.CF₃-BDP NPs could efficiently kill cancer cells through the photothermal conversion by near-infrared laser irradiation,and CF₃-BDP NPs are highly desirable for the photothermal therapy.In the third chapter of this thesis,a series of aza-BODIPYs bearing the subtus-fused rings with the-CH₂-X-（X=CH₂,O,S）chains were successfully prepared.By X-ray crystallographic analysis,the twisted degree of C-aza BDP with the subtus aryl-fused ring is severer than that of BODIPY with upper aryl-fused ring.Among them,S-aza BDP with twistedπ-conjugation system is demonstrated that shows efficient intersystem crossing（ISC）（singlet oxygen quantum yield,Φ_Δ=19%）,the favorable triplet quantum yield（Φ_T=13.7%）and a long triplet state lifetime（τ_T=25μs）.These triplet properties are superior to the classical tetraphenyl aza-BODIPY Ph-aza BDP（Φ_Δ=2%）.Therefore,regulating the subtus-fused rings structure in aza-BODIPY is a feasible design strategy for heavy-atom-free triplet photosensitizer.