1. Institute of Molecular Science, Key Laboratory of Chemical Biology and Molecular Engineering of the Education Ministry, Shanxi University, Taiyuan, Shanxi 030006, P. R. China
2. Key Laboratory of Materials for Energy Conversion and Storage of Shanxi Province, Shanxi University, Taiyuan, Shanxi, 030006, P. R. China
3. Department of Chemistry, University of North Texas CHEM 305D, 1508 W Mulberry St, Denton, TX, 76201, USA