1. Department of Chemistry and Key Laboratory for Preparation and Application of Ordered Structural Materials of Guangdong Province, Shantou University, Shantou, Guangdong Province 515063, P. R. China
2. Department of Medicinal Chemistry, Shantou University Medical College, Shantou, Guangdong Province 515041, P. R. China
3. School of Physical Science and Technology, MOE Key Laboratory of New Processing Technology for Non-ferrous Metals and Materials, Guangxi Key Laboratory of Processing for Non-ferrous Metals and Featured Materials, Guangxi University, Nanning, Guangxi Province 530004, P. R. China