1. Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v. v. i., Flemingovo nám. 2, 166 10 Praha 6, Czech Republic, Department of Physical and Theoretical Chemistry, Faculty of Natural Sciences, Comenius University, Mlynská Dolina, 842 15 Bratislava 4, Slovak Republic, and Department of Physical Chemistry, Palacky University, tr. Svobody 26, 771 46, Olomouc, Czech Republic