1. Université de Lyon, CNRS, ENS Lyon, Université Lyon 1, Centre de RMN à hauts champs de Lyon, UMR 5082, 5 rue de la Doua, Villeurbanne F-69100, France
2. Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 1-5/10, Zürich CH-8093, Switzerland
3. Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
4. U.S. DOE Ames Laboratory, Ames, Iowa 50011, United States