1. National & Local Joint Engineering Laboratory for New Petro-chemical Materials and Fine Utilization of Resources; Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education); Key Laboratory of the Assembly and Application of Organic Functional Molecules of Hunan Province; College of Chemistry & Chemical Engineering, Hunan Normal University, No. 36 South Lushan Road, Changsha 410081, Hunan, P. R. China