Executive Summary : | The interactions of nucleic acids with small fluorescent ¬molecules is an active research area and the synthesis of such type of fluorescent water soluble molecules is still a challenging task for scientists either by chemical or photochemical methods. Sometime the inability to obtain polycyclic aromatics compounds through traditional organic synthetic methods has prompted chemists to look for an alternative way, where photocyclization of stylbenes and their heterocyclic analogues has been considered as one of the most interesting photoinduced electrocyclization pathway. Most importantly, this cyclization process will be carried out in air saturated solutions of organic solvents or water media upon irradiation with direct or filtered light of a high-pressure Hg-vapor lamp at room temperature without using any catalysts but we will concern about the selection of analyte binding functionalities, which are unreactive towards photoreactions, since here only DNA binding charged backbone will be generated after photoreaction. In most cases, the binding interactions are easily detected by a change of the absorption and emission spectra of the dye upon DNA addition. And the fluorimetric detection of biomacromolecules has developed as a key method in this research area, mainly because emission spectroscopy is a highly sensitive and straightforward method with relatively few demands on the equipment. In this respect, various fluorescent probes, whose emission intensity increases significantly upon complex formation with DNA or proteins, are especially useful, specifically when the binding event to the host molecule is readily followed by the appearance of a strong fluorescence emission (“light¬up probes”). This significant fluorescence enhancement upon DNA binding of the fluorescence probes is often applied in analytical biochemistry, biology, and also in medicine. In addition, the sensing of various analytes which may be located in the close vicinity of cellular DNA [Reactive Oxygen Species (ROS), H2S, and metal ions] is also well established in the chemosensor field. The aim and challenge of my project is the combination of two types of sensing phenomena in one molecular platform i.e to develop a probe that associates with DNA and that has also the ability to bind ROS, H2S or metal ions with an additional functionality. Both binding events should have a significant influence on the excited¬ state processes of the probe and hence onits emission properties. The interactions of the probe with DNA and with the second small molecule analyte results a fluorescence light¬up effect that is only effective when both DNA and analyte are bound simultaneously, thus opening novel opportunities for the detection of two different types of analytes with just one molecular probe. |