1. College of Chemistry and Chemical Engineering, State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao 266580, P. R. China
2. Key Laboratory of Theoretical and Computational Photochemistry of Ministry of Education, Department of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
3. Key Laboratory of Magnetic Molecules & Magnetic Information Materials of Ministry of Education, School of Chemistry and Materials Science, Shanxi Normal University, Taiyuan 030032, P. R. China
4. College of Chemistry and Molecular Sciences, Henan University, Kaifeng, Henan 475004 P. R. China