Synthesis and spectroscopic characterisation of fluorescent indicators for Na+ and K+
作者:Els Cielen、Abdellah Tahri、Katja Ver Heyen、Georges J. Hoornaert、Frans C. De Schryver、Noël Boens
DOI:10.1039/a802183j
日期:——
The synthesis and the spectral and cation binding properties of new fluorescent indicators for Na+, dicaesium 5-[5-(2,3,5,6,8,9,11,12-octahydro-1,4,7,10,13-benzopentaoxacyclopentadecin-15-yl)-2-thienyl]isophthalate (Benzos), and for K+, dicaesium 5-[5-(2,3,5,6,8,9,11,12,14,15-decahydro-1,4,7,10,13,16-benzohexaoxacyclooctadecin-18-yl)-2-thienyl]isophthalate (Benzop), are reported. Both indicators consist of a benzocrown ether with an appropriate cavity for the sodium and the potassium cation, respectively, linked to an aryl thiophene fluorophore. In aqueous solution, the indicators have an absorption maximum at 340 nm and an emission maximum at 430 nm. The chelating abilities of Benzos and Benzop with Na+, K+, Li+, Cs+, Mg2+ and Ca2+ were studied by means of their fluorescence properties. Upon cation binding, a change in the fluorescence intensity is observed, whereas the spectral distribution remains unaltered. While Benzos cannot discriminate between Na+ and other monovalent cations, Benzop shows a three-fold selectivity for K+ over Na+.
报道了新型荧光钠指示剂双铯5-[5-(2,3,5,6,8,9,11,12-八氢-1,4,7,10,13-苯并五氧杂环十五烷-15-基)-2-噻吩基]异酞酸酯(Benzos)和新型荧光钾指示剂双铯5-[5-(2,3,5,6,8,9,11,12,14,15-十氢-1,4,7,10,13,16-苯并六氧杂环十八烷-18-基)-2-噻吩基]异酞酸酯(Benzop)的合成、光谱及阳离子结合性质。这两种指示剂均由一个苯并冠醚组成,该冠醚具有分别适合钠和钾阳离子的适当空腔,并通过一个芳基噻吩荧光团与之相连。在水溶液中,这些指示剂在340 nm处有最大吸收,在430 nm处有最大发射。通过它们的荧光性质研究了Benzos和Benzop与Na+、K+、Li+、Cs+、Mg2+和Ca2+的配位能力。在阳离子结合时,观察到荧光强度的变化,而光谱分布保持不变。Benzos不能区分Na+和其他一价阳离子,而Benzop对K+的选择性是Na+的三倍。