1. Department of Chemistry, Physical Chemistry, Electrochemistry, Dermatochemistry and Skin Allergy, Göteborg University, SE-412 96 Göteborg, Sweden, Department of Inorganic Environmental Chemistry, Chalmers University of Technology, SE-412 96 Göteborg, Sweden, and Theoretische Chemie, Fakultät für Chemie, Universität Bielefeld, Postfach 100131, 33501 Bielefeld, Germany