1. Department for Earth- and Environmental Sciences and Center for NanoScience (CeNS), Ludwig-Maximilians-University Munich, Theresienstrasse 41, D-80333 Munich, Germany, Department of Chemistry, Columbia University, New York, New York 10027, Center of Micro and Nanochemistry and Engineering, Organische Chemie I, Universität Siegen, Adolf-Reichwein-Strasse 2, D-57068 Siegen, Germany, and Deutsches Museum, Museumsinsel 1, D-80538 Munich, Germany