1. State Key Laboratory of Applied Organic Chemistry Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province College of Chemistry and Chemical Engineering Lanzhou University Lanzhou 730000 P. R. China
2. School of Materials Science and Engineering Shanghai Jiao Tong University Shanghai 200240 P. R. China
3. Department of Chemistry and Biochemistry The Ohio State University 100 West 18th Avenue Columbus OH 43210 USA