Abstract
We carried out the structure and stability analysis of β-diketones derivatives-group 13 metals and calix [4] arene derivatives-alkaline metals by molecular mechanics, semi-empirical molecular orbital, and density functional theory (DFT) methods.
The selectivity of β-diketones for aluminium (III) and indium (III) was examined by the liquid-liquid extraction method, and molecular mechanics calculations were performed for each complex with the MOMEC force field. The force field parameters, not yet available, were developed so that the calculated structures were fitted to the relevant Xray crystal structures. The calculations indicate that the quantitative structure-property relationship (QSPR) can be obtained. This relates the complexation strain energy differences among the metal complexes to their relative extractability.
A calix [4] arene carboxylic acid derivative was utilized as an extractant for alkaline metal ion separation. The host compound exhibited a high extractability to sodium ion compared to lithium ion and potassium ion. We also discussed the experimental results with a computaional modeling by means of semi-empirical molecular orbital and DFT methods. From the molecular geometries and heat of formation of the calix [4] arene derivative before and after extraction, the important factors for alkaline metal ion separation were found to be its cyclic structure and its cavity size.
