Produção Nacional
Revisado por pares
Theoretical spectroscopic studies and identification of metal-citrate (Cd and Pb) complexes by ESI-MS in aqueous solution
2014; Elsevier BV; Volume: 137; Linguagem: Inglês
10.1016/j.saa.2014.08.053
ISSN1873-3557
AutoresAlexandre C. Bertoli, Ruy Inácio Neiva de Carvalho, Matheus P. Freitas, Teodorico C. Ramalho, Daiana T. Mancini, M. Conceição Oliveira, Amarílis de Varennes, Ana Dias,
Tópico(s)Inorganic and Organometallic Chemistry
ResumoThe combined use of ESI-MS, FTIR-ATR and theoretical calculations for the determination of metal-citrate (metal = Cd and Pb) structures are reported. Mass spectrometry allowed to determine the stoichiometry 1:1 and 2:1 of the complexes, corroborating the theoretical calculations. The species found in the ratio 2:1 had their molecular structures readjusted, since the deprotonation of citric acid differed from what was simulated. The calculations of thermodynamic stability (ΔH0(aq.)) for the complexes obtained by B3LYP/LANL2DZ were more exoenergetic than those found by PM6. However, for both methods, the stability of the complexes follows a trend, that is, the lowest-energy isomers in PM6 are also the most stable in B3LYP/LANL2DZ. The infrared analysis suggested that carboxyl groups are complexation sites and hydrogen bonds can help in the stability of the complexes. The vibrational frequencies in B3LYP/LANL2DZ had a good correlation with the experimental infrared results.
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