Comparison of Two Molecular Design Strategies for the Development of an Ammonium Ionophore More Highly Selective than Nonactin
详细信息 查看全文
- 作者：Shin-ichi Sasaki ; Tsuyoshi Amano ; Gou Monma ; Takeshi Otsuka ; Naoko Iwasawa ; Daniel Citterio ; Hideaki Hisamoto ; and Koji Suzuki
- 刊名：Analytical Chemistry
- 出版年：2002
- 出版时间：September 15, 2002
- 年：2002
- 卷：74
- 期：18
- 页码：4845 - 4848
- 全文大小：90K
- 年卷期：v.74,no.18(September 15, 2002)
- ISSN：1520-6882
文摘
A series of ionophores for ammonium ion-selective electrodes was designed and synthesized, and their characteristics were examined. The design of the ionophores isbased on two different strategies: (1) introduction of bulkyblocking subunits (decalino groups) in 20- or 21-membered crown ethers (TD20C6 and TD21C6), the ringsize of which is expected to be suitable for selective NH4+recognition, as compared to the slightly smaller K+; and(2) preorganized tripodal ionophores based on a 6-foldsubstituted benzene ring in order to complementarilyrecognize the tetrahedral NH4+, in contrast to the spherical K+. Compared to nonactin, a natural product that isused as a representative NH4+ ionophore, the newlydeveloped TD20C6 showed higher NH4+ selectivity overK+ while retaining the selectivity over Na+ (log 
=-1.5 and log 
= -2.5). On the other hand, atripodal ionophore with pyrazole nitrogen atoms as NH4+binding sites showed high NH4+/K+ selectivity but suffered from increased Ca2+ interference (log 
=-2.1 and log 
= -1.6). As an overall conclusion, the cyclic ionophores TD19C6 and TD20C6 are thebest ammonium-selective ionophores developed to date.
=-1.5 and log = -2.5). On the other hand, atripodal ionophore with pyrazole nitrogen atoms as NH4+binding sites showed high NH4+/K+ selectivity but suffered from increased Ca2+ interference (log =-2.1 and log = -1.6). As an overall conclusion, the cyclic ionophores TD19C6 and TD20C6 are thebest ammonium-selective ionophores developed to date.