1. Laboratory of Organic Chemistry, ETH Zurich, 8093 Zurich, Switzerland
2. Institute of Chemical Sciences and Engineering, EPF Lausanne, 1015 Lausanne, Switzerland
3. Institute for Chemical and Bioengineering, ETH Zurich, 8093 Zurich, Switzerland
4. Scientific Center for Optical and Electron Microscopy, ETH Zurich, 8093 Zurich, Switzerland