1. Department
of Chemistry, Innovative Drug Research Center, Shanghai University, Shanghai, 200444, P. R. China
2. Key
Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic
Chemistry, Chinese Academy of Sciences, Shanghai, 200032, P. R. China
3. Laboratory
for Microstructures, Shanghai University, Shanghai, 200444, P. R. China
4. Department
of Biology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
5. Emory
NMR Research Center, Emory University, 201 Dowman Drive, Atlanta, Georgia 30322, United States