1. School of Engineering and Science, International University Bremen, P.O. Box 750 561, 28725 Bremen, Germany, Department of Chemistry and Biochemistry, Florida State University and National High Magnetic Field Laboratory and Center for Interdisciplinary Magnetic Resonance, Tallahassee, Florida 32306-4390, and Laboratoire de Chimie Physique, UMR 8000, CNRS, Equipe d'Electrochimie et Photoélectrochimie, Université Paris-Sud, Bâtiment 420, 91405 Orsay Cedex, France