| 摘要: | 我們成功的設計並合成對於無機陰離子具有特殊選擇性跟高靈敏度的螢光化學感應器 (BZ-1，BZ-2和BZ-5)，這些陰離子探針都具備了二醯胺吡咯 (bis-amide-pyrrole) 的官能基作陰離子的分子辨識單元並利用含螢光性質的quinoxaline官能基來當訊號傳遞單元。
在生化與環境科學的領域裡，陰離子的檢測極為重要並廣泛的運用，在儀器分析方面可利用紫外光-可見光吸收光譜與螢光放射光譜來探討螢光化學感測器與陰離子作用後的能量改變，且利用核磁共振來探討感測器離子的作用機制並增加其靈敏度以及偵測極限;我們設計的BZ-1利用氫鍵作用力與醋酸根離子、苯甲酸根離子、磷酸根離子作用，並在氟離子、氰離子、焦磷酸根離子、氰氧根離子有去質子化的反應。
當BZ-1和錸金屬作配位反應之後形成BZ-2，BZ-2化合物的醯胺鍵上的氫變得更具有極性，而且導致amide carbonyls比較缺電子，因此在amide carbonyls容易進行親核加成反應，而這個親核加成反應機制在BZ-2和氟離子、氰離子、醋酸根離子、苯甲酸根離子、磷酸根離子、焦磷酸根離子、氫氧根離子也是具有相同的作用，此外陰離子與BZ-2親核加成反應較弱的條件下則是形成氫鍵作用力。
BZ-5的化合物含有高共振系統的苯乙炔官能基，無法使結構上的二醯胺吡咯 (bis-amide-pyrrole) 醯胺鍵無法被極化像達到BZ-1和BZ-2的程度，所以BZ-5只能跟陰離子形成氫鍵作用力。
We report the synthesis, characterization, and photophysical properties of a series of colorimetric and luminescent probes (BZ-1, BZ-2, and BZ-5) for inorganic anions. These anion probes featuring bis-amide-pyrrole recognition sites for anion recognition and quinoxaline containing chromophores for singal transduction.
Anion recognition and sensing properties have been explored for a variety of biologically and/or environmentally important anions including F-, CN-, Cl-, H2PO4-. Detailed spectroscopic investigations by UV-vis absorption, fluorescence, and 1H NMR titration experiemtns have been carried to establish the sensitivity and binding modes between anions and probe molecules. BZ-1 formed hydrogen-bonding complex with OAc-, PhCOO-, H2PO4-, whereas deprotonation occurred when interacting with F-, CN-, HP2O73-, OH-.
Upon coordinating of BZ-1 to Lewis acidic rhenium tricarbonyl bromide moieties, not only the amide N-H protons become more polarized but also the amide carbonyls become more electron deficient, which is susceptible to nucleophilic addition. Indeed, the interaction mode between BZ-2 and F-, CN-, OAc-, PhCOO-, H2PO4-, HP2O73-, OH- is through nucleophilic reaction to form addition products. On the other hand, the weaker nucleophilicity of Cl-, Br-, I-, NO3-, HSO4-, only formed hydrogen-bonding complexes with BZ-2.
The incorporation of phenylethynyl moieties to bis-amide pyrrole unit resulted in less polarized N-Hs in BZ-5 than BZ-1 and BZ-2. Thus, BZ-5 formed only hydrogen-bonding complexes with F-, CN-, OAc-, H2PO4-, HP2O73-, OH-. |
