1. Department of Chemistry and Biochemistry , Northern Illinois University , DeKalb , IL , 60115 , USA
2. Department of Chemistry and Chemical Biology , Cornell University , Ithaca , New York 14853 , USA ,
3. Department of Chemistry , Coker University , Hartsville , SC , 29550 , USA
4. Department of Chemistry , Rock Valley College , Rockford , IL , 61114 , USA
5. Max-Planck-Institut für Festkörperforschung , Heisenbergstrasse 1 , D-70569 Stuttgart , Germany
6. Shanghai Institute of Ceramics , Chinese Academy of Sciences , Shanghai , 200050 , P. R. China