a
Dipartimento di Chimica, University of Perugia, Via Elce di Sotto 8, Perugia, Italy
E-mail: fcost@unipg.it
b
CNR – ICCOM, Via Madonna del Piano 10, Sesto Fiorentino, Italy
c
Department of Materials Science, University of Milano Bicocca, via, R. Cozzi, Milan, Italy
d
Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, USA