[1] Univ Bari Aldo Moro, Dipartimento Chim, Via Orabona 4, I-70126 Bari, Italy
[2] Univ Salento, CNR NANOTEC, Inst Nanotechnol, Campus Ecotekne,Via Monteroni, I-73100 Lecce, Italy
[3] Univ Salento, Dept Math & Phys Ennio De Giorgi, Campus Univ,Via Monteroni, I-73100 Lecce, Italy
[4] Westfalische Wilhelms Univ Munster, Phys Inst, Mendelstr 7, D-48149 Munster, Germany
[5] Covestro Deutschland AG, Chempk Leverkusen, D-51365 Leverkusen, Germany
[6] Univ Strasbourg, Inst Sci & Ingn Supramol, 8 Allee Gaspard Monge, F-67083 Strasbourg, France
[7] CNRS, 8 Allee Gaspard Monge, F-67083 Strasbourg, France