1. a Marine Bio-products Engineering Group , Dalian Institute of Chemical Physics, Chinese Academy of Sciences , Dalian 116023 , China
2. b Department of Organic and Biomolecular Chemistry , University of Goettingen , Tammannstrasse 2, D-37077 , Goettingen , Germany
3. c Laboratory of Molecular Immunopharmacology , Kunming Institute of Zoology, Chinese Academy of Sciences , Kunming 650223 , P.R China
4. d Department of Inorganic Chemistry , University of Goettingen , Tammannstrasse 4, D-37077 , Goettingen , Germany
5. e Marine Bio-products Engineering Group , Dalian Institute of Chemical Physics , Chinese Academy of Sciences, Zhongshan Road 457, Dalian 116023 , China