1. Institute of Organic and Pharmaceutical Chemistry, National Hellenic Research Foundation, 48 Vas. Constantinou Ave., Athens 116 35, Greece, Molecular Sciences Institute, Universitat de València, Apartado 22085, València ES-46071, Spain, Accelrys Inc., Telesis Court, San Diego, California 92121, United States, and Department of Informatics and Computer Technology, Lamia Institute of Technology, Third Km Old National Road, 35100, Lamia, Greece