1. Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education of China), Hunan Normal University, Changsha, Hunan 410081, P.R. China
2. Eenheid Algemene Chemie, Faculteit Wetenschappen, Vrije Universiteit Brussel, Pleinlaan 2, Brussels 1050, Belgium
3. Beijing Kein Research Center for Natural Sciences, Beijing 100022, P. R. China
4. Research Computing Center, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina 27599-3420, United States
5. Department of Chemistry, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States