Photochemical synthesis of new ionophores and their application

我们研究了取代苯乙烯、乙烯基萘、乙烯基菲等苯乙烯衍生物的分子内[2+2]光环加成反应。光环化反应表现出系绳长度的依赖性，即系绳越长，产率越低。然而，如果使用低聚(氧乙烯键)作为系绳，则产量不依赖于长度，通常是定量的。这种趋势被认为是由于低聚(氧乙烯链)的柔性性质所致。我们被促使利用这种有效的反应来合成一种新型的冠醚化合物(所谓的冠醚)，并成功地培育了一种新的离子载体合成方法。典型的冠菲在固-液萃取中表现出较高的锂离子选择性，因此我们试图提高选择性，经过多次试验，发现简单而适当的修饰的具有两个环丁烷键(冠烷)的冠烷在萃取实验中对锂离子进行了专属和定量的萃取。其次，我们试图使冠冕对重金属离子的萃取有效。我们首先制备了一些在低聚(氧乙烯)键或芳香族核上带有两个羟基的前驱体，然后用吡啶甲基氯处理这些官能团。在液-液萃取实验中，含两个吡啶侧臂的改性冠醚对Ag~+离子表现出较高的亲和力。特别是在芳香族核上带有侧臂的化合物表现出良好的选择性。

We have developed intramolecular [2+2] photocycloaddition of styrene derivatives, such as substituted styrene, vinylnaphthalene, vinyiphenanthrene, and so on. The photocyclization showed tether-length dependency ; i.e., the longer the tether becomes, the lower yield is obtained. If oligo(oxyethylene) linkage is used as the tether, however, the yield does not depend on the length and generally becomes quantitative. This tendency has been determined to be due to the flexible property of oligo(oxyethylene) chain.We were prompted to use this efficient reaction to make a new type of crown compounds (so- called crownophanes) and succeeded in the cultivation of a new ionophore synthetic method.The prototypical crownophanes showed relatively high Li^+ ion selectivity on the solid-liquid extraction, so we tried to improve the selectivity and found, after several trials, that simply and appropriately modified crownophanes having two cyclobutane linkages (crownopaddlanes) extracted the Li ion exclusively and quantitatively on the extraction experiment.Next we tried to make crownophanes working efficiently for the extraction of heavy metal cations. We first made some precursors having two hydroxyl groups on the oligo(oxyethylene) linkage or the aromatic nuclei and then treated these functional groups with pyridylmethyl chloride. The modified crownophanes with two pyridine side arms showed high affinity toward Ag^+ ion on the liquid-liquid extraction. Especially, the compound having the side arms on the aromatic nuclei exhibited the excellent selectivity.