1. Department of Chemistry and Key Laboratory for Preparation and Application of Ordered Structural Materials of Guangdong Province, Shantou University, Shantou, Guangdong 515063, P. R. China
2. The Cancer Hospital of Shantou University Medical College, Shantou, Guangdong 515041, P. R. China
3. Department of Medicinal Chemistry, Shantou University Medical College, Shantou, Guangdong 515041, P. R. China
4. The Second Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong 515041, P. R. China
5. Chemistry and Chemical Engineering Guangdong Laboratory, Shantou, Guangdong 515063, P. R. China
6. Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The University of Hong Kong, Hong Kong S.A.R., P. R. China