1. Department of Chemistry, Boston University, 590 Commonwealth Ave, Boston, MA 02215, USA
2. Department of Chemistry, University of Michigan, Ann-Arbor Michigan 48109-1055, USA
3. Department of Chemistry, University of Toronto, 80 St George St, Toronto, ON M5S 3H6, Canada
4. Department of Computer Science, University of Toronto, 214 College St, Toronto, ON M5T 3A1, Canada
5. Institute of Nanotechnology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
6. Division of Materials Science and Engineering, Boston University, 15 St Mary's St. #117, Boston, MA 02215, USA