A series of 1,2,3-triazole-linked calix[4]arene ionophores comprised of different O-donor groups (OH, COOEt, CONEt2) attached either to the lower rim of calix or to the triazole moieties were synthesized to explore their ion-selectivity for the first time in potentiometric transduction. Plasticized PVC membrane electrodes (ISEs) were fabricated, and their potentiometric selectivities were measured toward a series of mono- and divalent metal ions. Structure-ion-selectivity relationship and the structural requirements of the coordination sphere for selective binding were established. ISEs made of calix[4]arene-bis-triazoles were found generally to exhibit distinct Ag+ selectivity in the order 3 ≈ 4 > 2 > 1, indicating the beneficial effect of the carboxamide or ester groups in the complexing site. In contrast, calix[4]arene-tetratriazole 5 comprised only sp 2 N-donor atoms displayed excellent Cu2+ selectivity over a series of alkali-, alkaline earth- and transition metal ions. A unique feature of the outstanding Ag+ selective electrodes made of 3 and 4 was recognized and suggested their potential application as Na+ ISEs in systems not containing silver ions. Further, the potential use of competitive ESI-MS experiments for screening the binding affinities of ionophores 3–6 to different metal ions was also demonstrated.
我们合成了一系列
1,2,3-三唑连接的
钙钛矿[4]炔离子体,这些离子体由连接在
钙钛矿下缘或三唑分子上的不同 O-供体基团(OH、COOEt、CONEt2)组成,首次探索了它们在电位转换中的离子选择性。制备了塑化聚
氯乙烯膜电极(I
SE),并测量了它们对一系列一价和二价
金属离子的电位选择性。建立了结构-离子-选择性关系以及选择性结合对配位层结构的要求。研究发现,由
钙[4]炔双三唑制成的 I
SE 通常具有明显的 Ag+ 选择性,其顺序为 3 ≈ 4 > 2 > 1,这表明羧酰胺基团或酯基团在络合位点上的有利作用。相比之下,仅由 sp 2 个 N-供体原子组成的
钙并[4]炔四三唑 5 对一系列碱
金属、碱土
金属和过渡
金属离子具有极佳的 Cu2+ 选择性。由 3 和 4 制成的杰出 Ag+ 选择性电极的独特性得到了认可,这表明它们有可能在不含
银离子的体系中用作 Na+ I
SE。此外,还证明了竞争性 ESI-MS 实验在筛选离子体 3-6 与不同
金属离子的结合亲和力方面的潜在用途。