Ligand Design Principle for Molecular Recognition and the Application to Separation Chemistry

点击翻译按钮获取中文摘要

Ion size recognition with conventional organic ligands was proved to be governed by several factors. The first is based on the distance between the donor atoms, that is, the bite size. Bite size in a 6-membered ring such as beta-diketone also governs not only the selectivity, but the acidity of the ligand. The second factor governing ion size recognition is the chelate ring rigidity. The third is the unstabilization of chelates based on the inter ligand contact, which is caused by bulky terminal group of the ligand.The application of the three requirments to the separation of rare earth and Group 13 metal ions was performed : The efficient extraction-separation of each metal ion in Group 13 by bulky 4-substituted acylpyrazolones confirms the validity of the factors on the role of the bite size and steric factors. The above results thus have proved the possibility of designing ligands of high selectivity for target metal ions by controlling the bite size of the ligand and/or creating intra- and interligand contacts.