A theoretical study on photobleaching mechanisms of hypocrellins

In this paper, quantum chemical method RHF/6-31G(d,p)//AM1 was employed to investigate the photobleaching behaviors of hypocrellins. It is found that frontier charge rather than Mulliken charge is an applicable parameter to predict the 1O2- and O2−-addition positions of the pigments; accordingly some experimental observations on the photobleaching mechanisms of hypocrellins were elucidated. In addition, some theoretical predictions that were not observed in the previous experiments will be helpful to direct the further study.