title: Structural determination of Cu and Fe-Citrate complexes: theoretical investigation and analysis by ESI-MS.
abstract: The combined use of ESI-MS (electrospray ionization-mass spectrometry) and theoretical calculations for the determination of citrate:metal (metal=Cu and Fe) 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 calculated structures readjusted, from what was originally simulated, since the deprotonation of citric acid differed from what was before simulated. The thermodynamic stability (ΔH(aq.)(0)) of the complexes optimized at the B3LYP/LANL2DZ level was more exoenergetic than for the complexes found by the PM6 semi-empirical method.
authors.affiliation: Departamento de Química, Universidade Federal de Lavras, UFLA, 37200-000 Lavras, MG, Brazil; Instituto de Química, Universidade Federal de Alfenas, UNIFAL, 37130-000 Alfenas, MG, Brazil. Electronic address: bertolialexandre@yahoo.com.br.
authors.forename: Alexandre C
authors.initials: AC
authors.lastname: Bertoli
authors.affiliation: Departamento de Química, Universidade Federal de Lavras, UFLA, 37200-000 Lavras, MG, Brazil.
authors.forename: Ruy
authors.initials: R
authors.lastname: Carvalho
authors.affiliation: Departamento de Química, Universidade Federal de Lavras, UFLA, 37200-000 Lavras, MG, Brazil.
authors.forename: Matheus P
authors.initials: MP
authors.lastname: Freitas
authors.affiliation: Departamento de Química, Universidade Federal de Lavras, UFLA, 37200-000 Lavras, MG, Brazil.
authors.forename: Teodorico C
authors.initials: TC
authors.lastname: Ramalho
authors.affiliation: Departamento de Química, Universidade Federal de Lavras, UFLA, 37200-000 Lavras, MG, Brazil.
authors.forename: Daiana T
authors.initials: DT
authors.lastname: Mancini
authors.affiliation: Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisbon, Portugal.
authors.forename: Maria C
authors.initials: MC
authors.lastname: Oliveira
authors.affiliation: Departamento de Química Ambiental, Instituto Superior de Agronomia, Universidade de Lisboa, 1399-017 Lisbon, Portugal.
authors.forename: Amarílis
authors.initials: A
authors.lastname: de Varennes
authors.affiliation: Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisbon, Portugal.
authors.forename: Ana
authors.initials: A
authors.lastname: Dias
mesh_terms: D002951:Citrates / Q000737:chemistry*; D056831:Coordination Complexes / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry*; D013058:Mass Spectrometry; D021241:Spectrometry, Mass, Electrospray Ionization; D013816:Thermodynamics
chemical_list: D002951:Citrates; D056831:Coordination Complexes; D005290:Ferric Compounds; C025314:ferric citrate; D003300:Copper; C111995:copper(II) citrate
keywords: Cu/Fe complexes; DFT; ESI-MS; PM6