title: Interaction between alkaline earth cations and oxo-ligands. DFT study of the affinity of the Ca2+ cation for carbonyl ligands.
abstract: The affinity of the Ca(2+) ion for a set of substituted carbonyl ligands was analyzed with both the DFT (B3LYP/6-31+G(d)) and semi-empirical (PM6) methods. Two types of ligands were studied: a set of monosubstituted [O=CH(R)] and a set of disubstituted ligands [O=C(R)(2)] (R=H, F, Cl, Br, OH, OCH(3), CH(3), CN, NH(2) and NO(2)), with R either directly bound to the carbonyl carbon atom or to the para position of a phenyl ring. The interaction energy was calculated to quantify the affinity of the Ca(2+) cation for the ligands. Geometric and electronic parameters were correlated with the intensity of the metal-ligand interaction. The electronic nature of the substituent is the main parameter that determines the interaction energy. Donor groups make the interaction energy more negative (stabilizing the complex formed), while acceptor groups make the interaction energy less negative (destabilizing the complex formed).
authors.affiliation: Programa de Pós-Graduação em Química, Instituto de Química, Universidade Federal Fluminense, Outeiro de São João Batista, Niterói, RJ, Brazil.
authors.forename: Leonardo Moreira
authors.initials: LM
authors.lastname: da Costa
authors.forename: José Walkimar de Mesquita
authors.initials: JW
authors.lastname: Carneiro
authors.forename: Gilberto Alves
authors.initials: GA
authors.lastname: Romeiro
authors.forename: Lilian Weitzel Coelho
authors.initials: LW
authors.lastname: Paes
mesh_terms: D002118:Calcium / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry*; D002412:Cations / Q000737:chemistry; D003198:Computer Simulation; D006860:Hydrogen Bonding; D008024:Ligands; D008673:Metals, Alkaline Earth / Q000737:chemistry*; D008956:Models, Chemical; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D002412:Cations; D008024:Ligands; D008673:Metals, Alkaline Earth; D009942:Organometallic Compounds; D014867:Water; D002244:Carbon; D002118:Calcium