Fluorescent Monitoring of Complexation of Phthalimide-Fused Crown Ethers with Alkali Metal Ions
作者:Joe Otsuki、Toshihiro Yamagata、Koji Ohmuro、Koji Araki、Toshio Takido、Manabu Seno
DOI:10.1246/bcsj.74.333
日期:2001.2
property was used to monitor the process of ioncomplexation and concomitant conformation changes. With the incremental addition of cesium ions (M) to the bis(crown ether)s (L), a folded sandwich complex (LM) initially formed, which subsequently transformed into a more extended LM2-type complex. This behavior, which was independently confirmed by 1H NMR spectroscopy, is clearly manifested in the fluorescence
A Bis-Crown Ether Derivative of Triaminotriazine: Synthesis and Behavior of the Ion-Selective and Hydrogen-Bonding Responsive Rotamers
作者:Joe Otsuki、Keith C. Russell、Jean-Marie Lehn
DOI:10.1246/bcsj.70.671
日期:1997.3
A bis-crown ether derivative of triaminotriazine was synthesized via a phthalic acid derivative of a polyether macrocycle obtained from benzo-18-crown-6. It exists in different conformers distinguishable by 1H NMR at room temperature, in which the macrocyclic side-arms take a closed, half-open, or fully open form, due to the rotational barrier of the C(triazine)–N bond. Large alkali metal ions, such as Rb+ and Cs+, the latter being particularly effective, promote the formation of the closed conformer. A barbiturate derivative also causes a similar equilibrium shift to the closed form by establishing complementary hydrogen bonds. The half-open and fully open conformers are induced by smaller alkali metal ions than Rb+, among which K+ is the most effective.