Design,Syntheses And Properties Of Aromatic-Ring-Fused BODIPY Derivatives And Analogs

BODIPYs,as boron complexed dipyrromethenes,are fascinating dyes with multiple modification sites and remarkable photophysical properties,such as highly chemical and photochemical stablilities,high molar absorption coefficients,and high fluorescence quantum yields.The facile functionalization of the BO DIPY chromophore renders their wide applications in biomedicine and material sciences.However,the absorption and emission of classical BODIPY chromophore at short wavelength limit their further applications.The dissertation focuses on the development of near-infrared?NIR?BODIPY derivatives and analogs with good spectral selectivity and excellent stability.1)Designed and synthesized a set of thiophene-fused BODIPYs,thiophene-fused aza BODIPYs,aromatic-ring-fused BOPHYs and thiophene-fused BF₂-azopyrrole complexes;2)Synthesized a new family of highly conjugated conformation-restricted partially-fused and fully-fused BODIPY dimers;3)Designed and synthesized a series of N₂O-type BOPHYs based on a one-pot condensation of formylisoindole,hydrazine and various boronic acids.The dissertation provides a good reference for the development of NIR BODIPY fluorescent dyes and its analogues,which mainly contains the following six chapters:1)In Chapter 1,several efficient structural modification strategies for realizing the absorption and emission wavelengths of BODIPY fluorescent dyes in the NIR region were introduced and summarized.2)In Chapter 2,the synthesis,structure and photophysical properties of a series of thiophene-fused BODIPYs and aza BODIPYs from readily available thieno[2,3-b]pyrroles and thieno[3,2-b]pyrroles have been reported.These thiophene-fused?aza?BODIPYs have near infrared absorptions/emissions and excellent photostability.Among them,thieno[3,2-b]pyrrole derivated azaBODIPYs show narrow absorption and emission in NIR range,while thieno[3,2-b]pyrrole derivated BODIPYs have the highest fluorescence quantum yields?upto 0.85 in chloroform?.In contrast,thieno[2,3-b]pyrrole derivated BODIPYs exhibit broad absorption bands from 500 to 880 nm.3)In Chapter 3,a set of highly stable conformation-restricted partially and fully fused BODIPY dimers?cyclohexadiene-fused and benzene-fused dimers?were synthesized from a one-pot condensation of 2-formylpyrroles with cyclohexadiene-fused bipyrrole.Effective expansion of?-conjugation over these fused BODIPY dimers was observed by X-ray analysis,density functional theory?DFT?calculations,electrochemical and optical measurements,as demonstrated by their strong absorption and emissions in NIR range.4)In Chapter 4,facile synthetic routes to a new class of red?-benzo-fused BOPHYs and?-thiophene-fused BOPHYs are presented.These dyes were characterized by X-Ray structure analysis,cyclic voltammetry and optical measurements.Comparing with parent BOPHY,significant red-shifts in the absorption and emission,as well as high chemical stability and photostability were found for these aromatic-ring-fused BOPHY dyes.5)In Chapter 5,a one-pot synthesis of a series of N₂O-type BOPHY fluorescent dyes has been achieved from the condensation of formylisoindole,hydrazine and various boronic acids.X-ray structures indicate that the boron atoms in these dyes adopt a tetrahedral arrangement and the connected axial substituted groups are in the apical site of the pyramidal arrangement.All these BOPHY analogues exhibit good solubility and excellent optical properties,including the red-shift of the absorption and emission in near-infrared region.6)In Chapter 6,a series of thiophene-fused BF₂-azopyrroles was successfully synthesized by the reaction of thienopyrrole s with diazonium salts and the subsequent BF₂complexation.X-Ray structure analysis,optical measurements,cyclic voltammetry,and DFT calculations show effectively enhancing?-electron delocalization over these dyes.All these BF₂-azopyrrole complexes show red/NIR absorption and emission,as well as good stability.