1. Institute of Polymer Chemistry, Johannes Kepler University Linz; Welser Straße 42 Leonding A-4060 Austria
2. Institute of Organic Chemistry, Johannes Kepler University Linz; Altenberger Straße 69 Linz A-4040 Austria
3. Faculty of Science, University of South Bohemia; Branisˇovská 31 Cˇeské Budeˇjovice 370 05 Czech Republic