1. Institute of Organic Chemistry, University of Hamburg, Martin Luther King Platz 6, D-20146 Hamburg, Germany, GKSS Research Centre, Max Planck Straβe 1, D-21502 Geesthacht, Germany, Nanotechnology Research Institute, AIST, 1-1-1 Higashi, Tsukuba Central 5, Tsukuba, Ibaraki 305-8565, Japan, and Gesellschaft für Biotechnologische Forschung mbH, Mascheroder Weg 1, D-38124 Braunschweig, Germany