1. Laboratory for Macromolecular and Organic Chemistry, Group Theoretical and Polymer Physics, and Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands, Dutch Polymer Institute, P.O. Box 902, 5600 AX Eindhoven, The Netherlands, Laboratory for Chemistry of Novel Materials, University of Mons-Hainaut, B-7000 Mons, Belgium, and High Field Magnet Laboratory, Institute of Molecules and Materials, Radboud University Nijmegen, Toernooiveld 7,...