1. Department of Chemistry, Indiana University, Bloomington, Indiana 47405, Institut für Festkörperforschung, Forschungszentrum Jülich, Postfach 1913, D-52425 Jülich, Germany, A. N. Nesmeyanov Institute of Organoelement Compounds, Moscow 117813, Russia, Tver Technical University, Tver 170026, Russia, and Departments of Chemical Engineering and Materials Science & Engineering, North Carolina State University, Raleigh, North Carolina 27695