1. Departmento de Química, Universidade Federal de Santa Catarina, 88040-900, Florianópolis, Santa Catarina, Brazil
2. Instituto de Química, Universidade de São Paulo, C. Postal 26077, São Paulo-SP, 05599-970, Brazil
3. Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106
4. Department of Chemistry and Chemical Biology, Wright & Rieman Laboratories, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08903