1. College of ChemistrySichuan University Chengdu 610064 P.R. China
2. Department West China School of PharmacySichuan University Chengdu 610064 P.R. China
3. National Laboratory for Molecular SciencesCentre for Molecular SciencesState Key Laboratory for Structural Chemistry of Unstable, and Stable SpeciesInstitute of ChemistryChinese Academy of Sciences Beijing 100190 P.R. China