1. Department of Organic Chemistry; University of Campinas-Institute of Chemistry, Rua Josué de Castro, s/n-Cidade Universitária Zeferino Vaz; P.O. Box 6154 13083 Campinas SP Brazil
2. Max-Planck-Institut für Kohlenforschung; Kaiser-Wilhelm-Platz 1 45470 Mülheim an der Ruhr Germany