A novel thiacalix[4]arene ditopic receptor with 1,3-alternate conformation and possessing two complexation sites for hard and soft cations, 5,11,17,23-tetra-tert-butyl-25,27-bis[(N,N-diethylaminocarbonyl)methoxy]-26,28-bis[(pyridylmethyl)oxy]-2,8,14,20-tetrathiacalix[4]arene is prepared. Regioselective synthesis of distal-bis[(N,N-diethylaminocarbonyl)methoxy]thiacalix[4]arene is accomplished by a protection-deprotection method using benzyl groups as a protecting group. The deprotection of benzyl group was succeeded in the presence of solid superacid (Nafion-H) under refluxing benzene. Its complexation behavior is examined by 1H-NMR titration experiments. The formation of 1:2 homo- and heteronuclear complexes demonstrates that the preorganization, subtle conformational changes and affinity have a pronounced effect on the complexation of the receptor.
本研究制备了一种新型的
硫杂[4]炔二位受体,它具有 1,3 备选构象,并拥有硬阳离子和软阳离子的两个络合位点,即 5,11,17,23-四叔丁基-25,27-双[(N,N-二乙基
氨基羰基)甲氧基]-26,28-双[(
吡啶基甲基)氧基]-2,8,14,20-四
硫杂[4]炔。以苄基作为保护基团,通过保护-去保护的方法完成了远端双[(N,N-二乙基
氨基羰基)甲氧基]
硫杂[4]炔的区域选择性合成。在苯回流的条件下,在固体超酸(Nafion-H)的存在下成功地实现了苄基的脱保护。通过 1H-NMR 滴定实验对其络合行为进行了检验。1:2 同核和异核络合物的形成表明,预组织、微妙的构象变化和亲和力对受体的络合有明显的影响。