Design and synthesis of highly selective ammonium ion ionophores and the preoaration of high performance ammonium ion selective sensors based on the ionophores

研究发现，以二苄基醚(DBC)为底物的膜电极对K~+、Na~+离子具有较高的选择性。本文提出了DBE与NH_4~+的络合模型，即通过氢键形成4：1络合物。通过研究在苯基对位引入供电子基团和吸电子基团的影响，确定了影响苄基醚络合铵离子的因素。讨论了苯基的参与以及苯基亚甲基基团对离子载体柔韧性的影响，认为二苄基醚的氨离子选择性主要是由乙醚中的氧原子作为中心给体原子来实现的。在苯基单元中，亚甲基单元的灵活性对于促进苯基单元的自由移动以适应离子的大小和电荷分布…是重要的更多的n和铵离子的取向。在苄基单元中引入给电子基团或吸电子基团影响了合成化合物的氨离子选择性。设计并合成了二醚和四醚化合物，与单醚相比，双醚和四醚与铵离子形成了更稳定的络合物，因为与单醚相比，它们具有更多的给体原子。将两个二苄氧基单元与烷基链连接，提高了离子载体对铵离子的选择性。丁烯桥装置最适合于这一目的。在与乙醚氧原子相邻的碳原子中引入了一个四甲基单元，从而产生了合成离子载体的结构刚性。四甲基单元也被认为是阻止其他离子与离子载体形成络合物的“阻断单元”。离子载体分子中的苯基单元和丁烯桥段的四甲基封闭单元的离子载体组合对K~+有较高的选择性。最后，我们得到了一种新型的脱醚离子载体--二苄基-1，1，4，4-四甲基丁基醚，它是目前所开发的氨离子载体中选择性最高的。较少

We found that the membrance electrode based on dibenzyl ether (DBC) exhibited a high selectivity to ammonium ion (NH_4^+) over K^+ and Na^+. Here we proposed a model for the complexation of DBE and NH_4^+, that is, the formation of a 4 : 1 complex by hydrogen bonds. Our investigation was directed to determine the factors that affect the complexation of the ammonium ion by benzyl ether, by studying the effect of the introduction of electron donating groups and electron withdrawing groups in the para position of the benzyl group. The participation of phenyl group and the influence of the flexibility of the ionophore through the methylene units of the benzyl group was also discussed.The ammonium ion selectivity behavior of dibenzyl ether was mainly thought to be born by the ether oxygen atom as the central donor atom. Flexibility of the methylene unit in the benzyl unit was important to facilitate the phenyl units free movement to accommodate the size of the ion and the charge distributio … More n and orientation of the ammonium ion. Introduction of electron-donating groups or electron-withdrawing groups in the benzyl units affected the ammonium ion selectivity of the synthesized compounds. The aromatic system of benzyl units was also found to take part in the complexation of the ammonium ion, whereas the pi-electron of the allyl groups were evident not as effective as the benzyl units.The di-and tetra-ether compounds were designed and synthesized, which were expected to form more stable complexes with the ammonium ion compared to the mono-ether such as DBE,because they have a higher number of donor atoms compared with the mono-ether. Connecting the two dibenzyloxy units with the alkyl chain increased the ammonium ion selectivity of the ionophore. The butylene bridge unit was the best suited for such a purpose. The introduction of a tetramethyl unit in the carbon atoms adjacent to the ether oxygen atoms produced structural rigidity of the synthesized ionophore. The tetramethyl units were also thought to serve as 'blocking units' to prevent other ions from forming complexes with the ionophore. The ionophore bearing combination of the benzyl unit, the tetramethyl blocking unit at the butylene bridge section in the ionophore molecule exhibited higher ammonium selectivity over K^+. finally we obtained the novel de-ether ionophore, dibenzyl-1,1,4,4-tetramethylbutyl ether, which gave the highest ammonium ion selectivity among all the ammonium ionophores developed to date. Less