1. Department of Chemistry and Biochemistry, University of Montana, Missoula, Montana 59812, United States
2. Department of Chemistry─BMC, Organic Chemistry, Uppsala University, Husargatan 3, 752 37 Uppsala, Sweden
3. Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
4. Swedish NMR Center, University of Gothenburg, Gothenburg SE-405 30, Sweden