1. Institute
of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 166 10 Prague 6, Czech Republic
2. Laboratoire
de Chimie Physique CNRS UMR 8000, Université Paris-Sud. Bât. 349, 15, rue Jean Perrin, 91405 Orsay Cedex, France