1. Technical Institute of Fluorochemistry (TIF), Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering, Nanjing Tech University, 30 South Puzhu Road, Nanjing 211816, P. R. China
2. College of Science, Hebei Agricultural University, Baoding 071001, P. R. China
3. Department of Pharmacy, School of Medicine, Zhejiang University City College, No. 48, Huzhou Road, Hangzhou 310015, P. R. China
4. Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, United States