1. Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources; Guangxi Normal University; Guilin 541004 P. R. China
2. Wuhan National High Magnetic Field Center; Huazhong University of Science and Technology; Wuhan 430074 P. R. China
3. Institut de Chimie de Strasbourg, CNRS-UMR 7177; Université de Strasbourg; 67070 Strasbourg France
4. College of Chemistry and Chemical Engineering; Hubei University; Wuhan 430062 P. R. China