1. Department of Chemistry, University of Rome “La Sapienza”, I-00185 Rome, Italy
2. Department of Chemistry, Chemical Engineering and Materials, University of L'Aquila, I-67100 L'Aquila, Italy
3. Institute of General and Analytical Chemistry, Budapest University of Technology and Economics and Structural Chemistry Research Group of the Hungarian Academy of Sciences at Eötvös University, P.O. Box 91, H-1521 Budapest, Hungary