1. Institute of Chemistry, Federal University of Rio Grande do Sul, UFRGS, Av. Bento Gonçalves 9500, 91501-970, Postal Box 15003, Porto Alegre, RS, Brazil, ,
2. Inorganic Chemistry Department, University of Yaoundé I, P.O. Box 812, Yaoundé, Cameroon
3. Federal University of Pampa (UNIPAMPA), Travessa 45, #1650, 96413-170, Bagé, RS, Brazil
4. Department of Chemistry, State University of Londrina, UEL, Londrina, PR, Brazil