Synthesis And Property Study Of BOKIPY Dyes

Boron-dipyrromethene (BODIPY) dyes have outstanding spectral properties, such as high fluorescent quantum yields (Φf), high molar extinction coefficients (ε), excellent photostability, less sensitivity to solvent polarity and pH, and narrower absorption and emission spectra that can be easily tuned through structural modifications. The rich chemistry of BODIPYs and their outstanding properties have provided them various applications in the fields such as laser dyes, energy transfer cassettes, fluorescent switches, harvesting arrays, solar cells, photosensitizers. This thesis is mainly focused on the modification of the BODIPY skeleton, from which a series of photosensitizers were generated. The work presented in this thesis is summarized in the following:1. Electrophilic bromination of pyrrolic-unsubstituted BODIPYs1with bromine, from which the regioselectively brominated BODIPYs2-3were generated in a stepwise fashion in good to excellent yields. These resultant bromoBODIPYs were further applied for the regioselective substitution and Suzuki coupling reaction to generate BODIPYs4-7in good to excellent yields. The spectroscopic properties of these resultant BODIPYs were studied, which show the potential applications of these bromoBODIPYs as sensitizers for PDT. The regioselectively stepwise bromination and their subsequent regioselectively electrophilic substitution reactions first take place at2,6-, then at3,5-and eventually at1,7-positions, whereas the regioselective nucleophilic substitution occurs first at3,5-then at1,7-positions of the chromophore.2. Using the ready-made β-formylBODIPYs1as a platform, a set of meso-β/meso directly linked bisBODIPYs2a-i were synthesized and characterized via NMR and X-ray diffraction. The spectroscopic properties and their singlet oxygen generation efficiencies have been investigated. The orthogonality of the bisBODIPYs2a-d greatly affects their efficiencies in the singlet oxygen generation.