1. Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, and Center for Biomolecules and Complex Molecular Systems, Flemingovo nám. 2, 16610 Prague 6, Czech Republic, Material Science Division, Regional Research Laboratory, Jorhat-785 006, Assam, India, and Institut für Physikalische und Theoretische Chemie, Universität Regensburg, D-93040 Regensburg, Germany