A pH responsive ratiometric fluorescent chemosensor based on attenuated energy transfer

ORGN 556

Jiba Raj Acharya, jachar1@lsu.edu, Xian Li, and Evgueni E. Nesterov, een@lsu.edu. Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803
Conjugated p-electron systems represent one of the most important classes of transduction materials that transform a chemical signal to an easily measurable electrical or optical output. This is due to the fact that their important properties such as charge transport, emission intensity and efficiency of exciton migration can be simply attenuated by external stimuli, leading to considerable changes in observable signals. We have developed a general approach to ratiometric (color changing) fluorescent sensors. The operative principle of these sensors is based on the ability to efficiently control the photoexcitation energy transfer in extended p-conjugated system by analyte binding. Herein we report the synthesis and study of pH responsive ratiometric fluorescent sensor designed based on this approach that is composed of oligo(p-phenylene-ethynylene) unit as a conjugated core terminated with fluorescein as a pH sensing unit.