1. Theoretical and Physical Chemistry InstituteNational Hellenic Research Foundation 11635 Athens Greece
2. Department of ChemistryUniversity of North Texas, 305070 Denton TX 76203-5017 USA
3. Área de Química Orgánica, Instituto de BioingenieríaUniversidad Miguel Hernández 03202 Elche Spain
4. Department of ChemistryNagoya University Nagoya 464-8602 Japan