Journal of the Brazilian Chemical Society
versión impresa ISSN 0103-5053
COSTA, Leonardo M. da; PAES, Lílian W. C. y CARNEIRO, José Walkimar de M.. Ab Initio, DFT and semi-empirical studies on interactions of phosphoryl, carbonyl, imino and thiocarbonyl ligands with the li+ cation: affinity and associated parameters. J. Braz. Chem. Soc. [online]. 2012, vol.23, n.4, pp. 648-655. ISSN 0103-5053. http://dx.doi.org/10.1590/S0103-50532012000400009.
The affinity of the Li+ cation for a set of para-substituted phosphoryl, carbonyl, imino and thiocarbonyl ligands was calculated with the ab initio MP2/6-311+G(d,p), DFT B3LYP/6-311+G(d,p) and semi-empirical PM6 methods. Each set of ligand is constituted by the following para-substituted groups: NH2, OCH3, CH3, H, Cl, CN and NO2. The interaction enthalpy was calculated to quantify the affinity of the ligands for the Li+ cation. Geometric and electronic parameters were correlated with the strength of the metal-ligand interaction. The electronic nature of the para-substituted group is the main parameter that modulates the intensity of the metal-ligand binding energy. Electron donor groups make the interaction enthalpy more exothermic, whereas electron acceptor groups make the interaction enthalpy less exothermic. The energy decomposition analysis shows that the para-substituted groups modulate the intensity of the electrostatic component of the interaction without affecting the covalent component.
Palabras llave : lithium cation; substituent effect; interaction enthalpy; EDA; ligand interaction.