Development of Highly Sensitive and Selective Fluorogenic Chemdosimeters

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In this project funded by the Chemical Structure, Dynamic & Mechanism B program and the Chemical Measurement & Imaging program of the Chemistry Division, Professor Kazunori Koide of the Department of Chemistry at the University of Pittsburgh will develop new classes of chemical reagents with useful fluorescence properties. The goal of this research is to exploit the characteristics of hydrogen peroxide and mercury for the development of fluorescence detection methods. The project lies at the interface of organic, analytical, inorganic, and biological chemistry, and is therefore well suited to the education of scientists at all levels. This group is also well-positioned to provide interdisciplinary education and training for undergraduate and graduate students and post-doctoral researchers. Outreach activities involving freshman college students will be part of the project. Specifically, chemosensors that fluoresce when exposed to mercury or hydrogen peroxide will be developed. For mercury detection, the principal investigator proposes to exploit organic reactions catalyzed by mercury. The catalytic systems will amplify fluorescence signals, yielding highly sensitive analytical methods. The catalytic reactions include a sigmatropic rearrangement and a cyclization reaction, both of which will produce a fluorescent product from a nonfluorescent starting material upon exposure to mercury species. These methods will be applied to the analyses of wastewater from coal-fired power plants. Mercury will be quantified below 0.1 ppb levels. For hydrogen peroxide detection and quantification, a [2,3]-sigmatropic rearrangement mediated by hydrogen peroxide, which creates a green fluorescent dye from a nonfluorescent precursor, will be used. The objective is to develop new probes for detecting and quantifying hydrogen peroxide in living human cells. Toward this objective, nonfluorescent rearrangement substrates will be made. When the substrates react with hydrogen peroxide and the rearrangement occurs, a green fluorescent fluorescein derivative will be produced.