1. Department of Water Engineering and of Chemistry (DIAC) Polytechnic of Bari, and C.N.R. ICCOM‐Sezione di Bari, 4 Via Orabona, 70125 Bari, Italy, Fax: +39‐080‐596‐3611
2. Department of Organic Chemistry, University of Florence, 13 Via della Lastruccia, 50019 Sesto Fiorentino (FI), Italy
3. Department of Chemistry, University of Liverpool, P. O. Box 147, L69 7ZD Liverpool, UK