Quantitative structure-property relationship of extraction equilibria of lanthanoid series using molecular mechanics calculations

A novel molecular mechanics force field for lanthanoid complexes coordinate d to O atoms of phosphate, phosphonate, carboxylate, and aqua type ligands is presented. The ligand-metal-ligand (L-M-L) bending interaction is modele d with 1,3-nonbonded interactions (point on a sphere approach) and a harmon ic M-L stretching potential is used for the stretching modes. A quantitativ e structure property relationship (QSPR) could be obtained, which relates t he complexation strain energy difference between the lanthanoid cations and La (III) with their relative extractability. We consider that the molecula r mechanics is an efficient tool for the design of next-generation extracta nts of phosphate, phosphonate and carboxylate types having the specific lan thanoid (III) extractability properties.