1. Instituto de Química, Universidade de São Paulo, CP 26077, São Paulo 05599-970, Brazil
2. Instituto de Química, Universidade de São Paulo, CP 26077, São Paulo 05599-970, Brazil, and Department of Chemistry, Wake Forest University, Winston-Salem, North Carolina, 27109
3. Department of Chemistry, Davidson College, Davidson, North Carolina 28036, and Department of Chemistry, Wake Forest University, Winston-Salem, North Carolina, 27109