Molecular Design of Alkali Metal Ion Probes for Use in Aqueous Media

用选择性比色法测定了正（烷基）（2-羟基-5-硝基苯氧基）二苯并-1 - 6-冠-5(1)的碱金属阳离子。在含有亲脂性的db16c5显色离子载体的阴离子胶束溶液中，发现了Na^+的选择性比色行为受到胶束表面电荷的强烈影响。通过在DB16C5骨架中引入芘甲酰胺单元(2)，期望对Na^+结合产生荧光响应。研究发现，Na^+的结合促进了氟离子团中羧基胺部分的质子解离，导致了从给体羧基胺阴离子到芘受体的内部电荷转移（ICT），从而产生了有效的比例发射。Li^+和Cs^+均未引起荧光反应。因此，氟离子载体2在1:11 1,4 -二氧六烷-水（v/v）中表现出高Na^+选择性的双发射响应。苯并-15-冠-5 （B15C5）氟离子载体3可归类为光致电子转移（PET）传感器。基于b155c5部分在非水溶液中1:1的络合物形成能力，对3有中等的Na^+选择性。相反，在γ - cyd存在的情况下，3被发现可以作为一种新的离子探针，即使在Na^+存在的情况下，它对K^+也有很高的灵敏度和选择性。结果表明，在γ - cyd存在下，3形成2:1的配合物，对K^+具有高选择性，并且在水中表现出单体和二聚体的双重发射。

A selective colorimetry of alkali metal cations in aqueous micellar solution containingsym-(alkyyl)(2-hydroxy-5-nitrobenzyloxy)dibenzo-1 6-crown-5 (1) has been examined. Colorimetric behavior were found to be strongly affected by the surface charge of micellar species and a selective colorimetry of Na^+ was performed in the anionic micellar solution containing lipophilic DB 16C5 chromoionophore. By introducing pyrenecarboxamide unit into DB16C5 skeleton (2), a fluorescent response for Na^+ binding is expected. It was found that proton dissociation of the carboxamido moiety in fluoroionophore was promoted by Na^+ binding, which resulted in an efficient ratiometric emission due to internal charge transfer (ICT) from the donorcarboxamido anion to the pyrene acceptor. No fluorescent response was induced by the presence of Li^+ or Cs^+. Thus fluoroionophore 2 exhibited a dual emission response with high Na^+ selectivity in 4 : 1 1 , 4-dioxane-water (v/v). The benzo-15-crown-5 (B15C5) fluoroionophore 3 can be classified as a photoinduced electron transfer (PET) sensor. A moderate Na^+ selectivity is obtained for 3 based on a 1 : 1 complex formation ability of the B 1 5C5 moiety in a non-aqueoussolution. In contrast, 3 was found to work as a novel ion probe in the presence of gamma-CyD, and it achieved high sensitivity and selectivity for K^+ even in the presence of Na^+. The results revealed that 3 formed a 2 : 1 complex with high selectivity for K^+ in the presence of gamma-CyD, and it exhibited both monomer and dimer emission in water.