1. Department of Chemistry, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
2. Department of Applied Science, William & Mary, Williamsburg, Virginia 23185, United States
3. Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
4. Center of Interdisciplinary Magnetic Resonance, National High Magnetic Field Laboratory, Tallahassee, Florida 32310, United States
5. National Institute of Standards and Technology, Rockville, Maryland 20850, United States
6. Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland 20850, United States