1. Institute of Physical Chemistry, Polish Academy of Sciences, 01-224 Warsaw, Kasprzaka 44/52, Poland, Institute of Organic Chemistry, Polish Academy of Sciences, 01-224 Warsaw, Kasprzaka 44/52, Poland, and Institute of Organic Chemistry, ICM, Warsaw University, Pawinskiego 5a, 02-106 Warsaw, Poland, Technical University Braunschweig, Hagenring 30, 38106 Braunschweig, Germany