1. a Ningbo Institute of Technology, Zhejiang University , Ningbo, P. R. China
2. b Department of Chemistry , Zhejiang University , (Xi Xi Campus), Hangzhou, P. R. China
3. c Department of Applied Chemistry , East China Institute of Technology , Fuzhou, P. R. China
4. d Pharmaceutical Science Reseach Institute, Aston University, Aston Triangle , Birmingham, UK