1. Department of Chemistry, National and Kapodistrian University of Athens Panepistimiopolis, 15771 Athens, Greece
2. Department of Chemistry and Pharmacy, “St. Kliment Ohridski” University of Sofia, Bul. J. Baurchier 1, 1164 Sofia, Bulgaria
3. Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, Vassileos Constantinou Avenue 48, 11635 Athens, Greece