1. Institute of Inorganic Chemistry, University of Göttingen, Tammannstrasse 4, 37077 Göttingen, Germany, Institute of Physical Chemistry, University of Göttingen, Tammannstrasse 6, 37077 Göttingen, Germany, Department of Chemistry, Gulbarga University, Gulbarga, India, and Basell R & D Polymer Physics and Characterization, Industriepark, Hoechst, Frankfurt, Germany