Desıgn and synthesıs of pH sensetıve energy transfer casettes

In this project, pH sensitive BODIPY molecules based on substitution of pyridinethenyl and dimethylaminophenylethenyl groups are synthesized. By doing that, the direction change of energy transfer regarding to acidity of environment between two BODIPY moieties bound with 1,4- phenylene is aimed. For this purpose, the differences caused by acidity of the environment in their absorbance and emission spectra were examined. BODIPY molecules in the energy transfer cassette were functionalized with pyridinethenyl and dimethylaminophenylethenyl groups by using Knovnegel condensation reaction and at the end of analysis of the cassettes, red shifts or blue shifts were observed regarding to pH of the environment. It is important that there is a switch mechanism between energy transfer and intersystem crossing for the deexcitation of the excited state molecule which can be related to pH changes. This type of molecule can be used for imaging and therapeutic action so in other words it is designed as unimolecular theranostic agent. This thesis includes a part of this long term project. With the results obtained by the study of BODIPY dimers, it is possible to foreseeing that energy transfer from BOIPY unit modified with dimethylaminophenylethenyl groups to BODIPY unit modified with heavy atoms (bromine) and pyridiylethenyl groups would cause cytotoxic singlet oxygen generation with the help of heavy atom effect.