1. Department of Chemistry, University Cheikh Anta Diop, Dakar, 10700, Senegal
2. Department of Chemistry, University of Nouakchott, Nouakchott, 130301, Mauritania
3. Facultad de Química, General Flores 2124, UdelaR, Montevideo, 11800, Uruguay
4. Instituto de Física de São Carlos, Universidade de São Paulo, CP 369, 13.560-970, São Carlos, SP, Brazil