1. University Laboratory School, University of Southern Mindanao, Kabacan, Cotabato, Philippines 9407
2. Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113
3. Institute of Chemistry, Chemical Research Center, Hungarian Academy of Sciences, P.O. Box 17, H-1525 Budapest, Hungary
4. Departamento de Química, Universidad de La Rioja, C/Madre de Dios 51, 26006 Logroño, Spain