1. Institute of Polymer Research, Hohe Strasse 6, D-01069 Dresden, Germany, Department of Polymer Chemistry, Chemnitz University of Technology, Strasse der Nationen 62, D-09111 Chemnitz, Germany, and Institute of Inorganic and Analytical Chemistry, Friedrich Schiller University, August-Bebel-Strasse 2, D-07743 Jena, Germany