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, H-1521 Budapest, and Structural Chemistry Research Group of the Hungarian Academy of Sciences at Eötvös University, P.O. Box 32, H-1518 Budapest, Hungary