1. Department of Exact and Applied Sciences, Federal University of Ouro Preto, Loanda, 35931-008 João Monlevade, MG, Brazil
2. Department of Chemistry, Federal University of Minas Gerais, Pampulha, 31270-901 Belo Horizonte, MG, Brazil
3. Institute of Chemistry of São Carlos, University of São Paulo, P.O. Box 780, 13560-970 São Carlos, SP, Brazil