ORGN 440 |
| Abstract: Fe3+ as transition metal ions play a crucial role in the growth and development of living systems. Numerous enzymes use iron as a catalyst for oxygen metabolism, electron transfer, and DNA and RNA synthesis. As a simple, efficient and economic method, the fluorescence detection has found its wide application in biological systems and environmental science. Many excellent fluorescent indicators of transition metal ions have been reported, such as Cu2+, Pb2+, Zn2+, Hg2+ and so on. However, there are a few Fe3+-induced fluorescent sensors reported. Because of the paramagnetic nature of ionic iron, these receptors are often signaled by fluorescence quenching, such as analogues of ferrichromes or siderophores. The suitable fluorescent iron indicator is important in recent application-oriented research. Herein, a fluorescent sensor for Fe3+ has been described. It was synthesized from rhodamine B. This sensor is based on the Fe3+-controlled opening of spirolactam-ring and Fe3+ coordination in a rhodamine dye. It shows an extreme selectivity for Fe3+ over other metal ions examined in water. Upon the addition of Fe3+, the colorless sensor displays red colour (ëab 562 nm) and strong orange fluorescence emission (ëem 583 nm) in aqueous solution and organic solvents while the other metal ions have no such response. With a low pKa of 4.55 ± 0.02, the sensor is insensitivity when pH is above 5.0. The fluorescence detection of Fe3+ with 1 could be made in a wide pH range (pH > 5.0). |
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Heterocycles and Aromatics, Molecular Recognition and Self Assembly
8:00 PM-10:00 PM, Tuesday, April 8, 2008 Morial Convention Center -- Hall A, Poster
Division of Organic Chemistry |