1. Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 2, Zürich CH-8093, Switzerland
2. Université de Lyon, Université Claude Bernard Lyon I, CNRS, INSA, CPE, UMR 5246, ICBMS, Rue Victor Grignard, Villeurbanne Cedex F-69622, France
3. Paul Scherrer Institut, Villigen CH-5232, Switzerland