1. Department
of Chemistry “Ugo Schiff”, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy
2. Department
of Chemistry and Industrial Chemistry, University of Pisa, Via Moruzzi
3, 56124 Pisa, Italy
3. Eni S.p.A., Centro Ricerche per le Energie
non Convenzionali, Istituto Eni-Donegani, Via G. Fauser 4, 28100 Novara, Italy