1. Department of Physical and Macromolecular Chemistry, Charles University in Prague, Hlavova 2030, 128 40 Prague 2, Department of Analytical Chemistry, Institute of Chemical Technology, Technicka 5, 166 28 Prague 6, and Institute of Organic Chemistry and Biochemistry, Academy of Science of the Czech Republic, Flemingovo n.2, 166 10 Praha 6, Czech Republic