Synthesis And Property Research Of Novel 3,5-Functionalization BODIPY Dyes

Boron-dipyrromethene(BODIPY)dyes have attracted wide research interests in recent years due to their excellent properties,such as high fluorescent quantum yields,high molar extinction coefficients,narrow emission band,maximum absorption and emission wavelengths in the visible region,good photostability and easy functionalization.They have found applications in a highly diverse research fields in biological detection,analytical chemistry,optical engineering,and material science.This thesis mainly consists of three chapters.In Chapter 1,a general and efficient method for α-chlorination of BODIPYs has been studied using CuCl2 as chlorination reagent.The reaction is characterized by complete 3/5-positions of BODIPY regioselectivity.This unusual highly regioselective α-chlorination of BODIPY is in sharp contrast to previously reported halogenation methods which preferred to occur first at the 2,6-positions of BODIPY.This approach provides a straightforward,facile,and economical route to 3-and/or 5-chloro-BODIPYs with various meso-groups(H,alkyl and aryl)and their derivatives.A plausible mechanism was proposed for this unusual ?-chlorination reaction as the first functionation of BODIPY through SET process.In Chapter 2,a metal-free direct α-selective arylation of BODIPYs has been studied based on base-mediated C-H functionalization with easily accessible diaryliodonium salts,which provides a straightforward facile access to a variety of α-arylBODIPY dyes.The α-regioselectivity was confirmed by X-ray analysis.The resultant dyes show strong absorption and emission over a broad range of spectra tunable via the simple variation of the diaryliodonium salts.This regioselective ?-arylation reaction may come through a radical process,and was studiedby DFT calculation.In Chapter 3,we developed a selective method for the coreextension of boron dipyrromethene(BODIPY)with two annulated indole rings with exclusive syn-connectivity based on a regioselective necleophilic substuition reaction of 2,3,5,6-tetrabromo BODIPY with arylamines,followed by palladium-catalyzed intramolecular C-C coupling ring fusion.The unsymmetrical core-expanded BODIPY with annulated indole and benzofuran rings was also synthesized by stepwise and regioselective necleophilic substuition and palladium-catalyzed intramolecular C-C coupling rection.The diindole-annulated BODIPY1 a was unambiguously characterized by single-crystal X-ray analysis.The optical properties of the present core--expanded BODIPYs showed clearly red-shifted absorption and emission bands with enhanced absorption coefficients and good fluorescence quantum yields upon annulation.