1. College of Chemistry, Zhengzhou University, Kexue Avenue 100, Zhengzhou, Henan 450001, P. R. China
2. Ministry of Education (MOE) Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry/School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou, Guangdong 510006, P. R. China
3. Zhengzhou Tobacco Research Institute, China National Tobacco Corporation, Zhengzhou, Henan 450001, P. R. China