1. Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973, United States
2. Facultad de Ciencias, Universidad Central de Venezuela, Caracas 1020-A, Venezuela
3. Zoneca-CENEX, R&D Laboratories, Alta Vista, 64770 Monterrey, México
4. Department of Chemistry, State University of New York at Stony Brook, Stony Brook, New York 11794, United States