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Ab Initio, DFT and semi-empirical studies on interactions of phosphoryl, carbonyl, imino and thiocarbonyl ligands with the li+ cation: affinity and associated parameters

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.

lithium cation; substituent effect; interaction enthalpy; EDA; ligand interaction


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