邻甲氧基羰基苄氧基取代杯[4]芳烃衍生物的合成及其性能研究

杯芳烃是继冠醚、环糊精之后的第三代主体分子1].据文献2,3]报道,在杯4]芳烃下沿酚氧原子上连接乙酸酯得到的四取代衍生物对Na+有很高的选择性,核磁与晶体结构研究均证实这是由于羧酸酯的羰基和酚氧基参与了对Na+的配位,而且配位基团所形成的包络空间大小与钠离子相匹配.一般认为,随着包络空间改变,对金属离子的识别作用会有所变化4].但目前对这方面的工作并没有给予更多的重视.我们发现,用2-溴甲基苯甲酸甲酯与杯4]芳烃反应,得到了一种新的四取代杯4]芳烃衍生物2]萃取研究结果表明,该化合物对钾离子有较好的选择性.此外,在合成该衍生物的过程中,还得到了另一新的二取代衍生物(3).

Studies on the Syntheses and Properties of o-Methoxycarbonylbenzyl Substituted Calix[4]arenes

Two new substituted calix4]arene derivatives 2 and 3 were synthesized by the reaction of calix4]arene with methyl o-bromomethyl-benzoate in the presence of potassium carbonate under nitrogen. Their compositions and structures were confirmed by elemental analysis, IR, ¹H NMRand ¹³C NMR. Both the compounds are in the cone conformation. The percent extraction of the tetrasubstituted calix4]arene derivative 2 for Li⁺, Na⁺, K⁺ and Cs⁺ are 6.8, 19.4, 69.8 and 7.1, respectively, indicating that derivative 2 extracts K⁺ better than Li⁺, Na⁺ and Cs⁺. The higher selective complexation of compound 2 with K⁺ elucidated that the radius of potassium cation may be matched with the inclusion cavity formed by the carbonyl and phenoxy groups. There is only a little extractivity of disubstituted calix4]arene derivative 3 for alkali metal ions.