Molecular Design of Highly Selective Ligand Controlling the Geometry of the Donating Atoms

用改性的β-二酮作溶剂萃取剂的研究表明，13族金属的络合作用依赖于络合物的咬合大小(络合环上的O-O距离)和配体间的接触。In络合物中的O-O距离是最长的之一，并且In的络合作用受到β-二酮α位取代基的干扰，从而阻止了咬合大小的扩大以适应络合物的结构。由于Al的离子半径非常小，其络合作用受配体间接触的影响很大。粗大的末端取代基降低了萃取率。考虑到这两个因素，我们成功地设计了13族金属的高选择性配体。合成了5个1-苯基-3-甲基-4-酰基-5-吡唑啉酮类化合物。由五元杂环5-吡唑啉酮衍生而来，证实了酰基吡唑酮衍生物的O-O距离比…长通过半经验MNDO/H计算，得到了更多的常规β-二酮化合物。由于它们的O-O距离很长，所以In的萃取不受干扰，在pH为1-2的条件下进行。虽然Al的离子半径远小于In的离子半径，但Al的萃取是在较高pH区进行的。考虑到酰基吡唑酮类化合物体积大，酸度相似，很明显铝的萃取是受配体间接触的影响。4位取代基体积越大，萃取率越低。用萘甲酰基吡唑酮类化合物可以实现铝和铟的定量分离。In的提取不依赖于取代基的大小。配体间接触的影响也体现在提取镓的过程中。萃取率与In相似，随着取代基体积的增大而减小。由于4-丙戊酰基和3-甲基之间的空间排斥作用，使得吡喃甲酰基吡唑啉酮的O-O距离变窄，In的萃取量接近Al的萃取量，从而实现了Ga与Al和In的定量分离。较少

Studies on the solvent extraction with the modified beta-diketones revealed that the complexations of group 13 metals depend on the bite size (O-O distance in the chelate ring) and the interligand contact in the complex. The O-O distance in the In complex is one of the longest and the complexation of In is disturbed by the substituent at the alpha-position of beta-diketone, which prevents the bite size from widening to fit the structure of the complex. The complexation of Al was found to be under the great influence of the interligand contact due to its remarkably small ionic radius. The extraction is lowered by the bulky terminal substituents. Highly selective ligands for group 13 metals have been successfully designed taking the two factors into consideration.Five 1-phenyl-3-methyl-4-acyl-5-pyrazolone derivatives have been prepared. Being derived from the five membered heterocyclic 5-pyrazolone, the O-O distances of the acylpyrazolone derivatives are confirmed to be longer than those … More of the conventional beta-diketones by the semiempirical MNDO/H calculations. Owing to their long O-O distances, the extraction of In was not disturbed and made at pH 1-2. The extraction of Al was made in the higher pH region, although its ionic radius is much smaller than that of In. Considering that the acylpyrazolones are bulky and their acidities are quite similar, it is clear that the extraction of Al is under the effect of the interligand contact. The extraction reduces as the substituent at the 4-position becomes bulkier. The quantitative separation of Al from In can be achieved with the naphthoylpyrazolones. The extraction of In does not depend on the size of the substituents. The effect of the interligand contact is also seen in the extraction of Ga. The extraction is similar to that of In and decreases as the substituents becomes bulkier. Owing to the steric repulsion between the 4-pivaloyl and 3-methyl groups, the O-O distance of pivaloylpyrazolone is narrowed and the extraction of In comes close to that of Al, resulting in a quantitative separation of Ga from Al and In. Less