界面微环境中双亲卟啉的光谱研究

UV-Vis Spectra of Amphiphilic Porphyrin in Microenvironment of Interface

用敏感于微环境变化的UV-Vis光谱,研究了在SDS胶束微环境中,双亲原卟啉P1对体相pH值的依赖关系。体相pH值由弱碱性到强酸性改变的过程中,P1在SDS胶束内存在明显等色点,为一典型的双组分平衡,同时其质子化峰吸收强度逐渐增强,表明P1在胶束内发生了质子化;体相pH值从弱碱到强碱变化时,P1的Soret带红移,吸光度变小,半峰宽加大,这是卟啉从SDS胶束内核转移到胶束表面的结果,由此证明改变pH值可以实现卟啉跨膜转移的控制。

Taking advantage of the microenviroment susceptibility of their Soret band and Q band, UV - Vis spectra were used to study the dependence of the porphyrins location in SDS micellar media on the pH value of bulk solution. Isobestic points in SDS micellar solution were observed clearly as the pH values varied from weak basicity to strong acidity during the pH titration process of P1, suggesting that it was a typical two component equilibrium. At the same time, the absorbance at 698 nm increased, indicating that P1 could be protonated in SDS micellar solutions. The red shift of the Soret band, the decrease of its absorbance and the increase of the full width at half-maximum（FWHH） of PI with pH titration process from weak basicity to strong basicity were attributed to the transfer process of the porphyrin moiety from the inner core to the outer surface of the micelles. Therefore, we can control the transmembrane transfer process of porphyrin moiety by changing the pH value of the bulk solutions.