Stern-Volmer Behavior of Organic Photocatalysts

Viologens are the diquaternary salts of 4,4'-bypridine. They have many applications, such as herbicides, electron transfer relays, charge transfer complex components, redox indicators, electrochromic switches, as well as many other uses. However, photophysical and photochemical studies of viologens are rare. The purpose of this project was to utilize Stern-Volmer kinetics to study how the fluorescence properties of the 5,10-dimethyl-5,10-diaza[5]helicene bis-tetrafluoroborate viologen change in the presence of several different organic quenchers and varying concentrations of the quenchers. This presentation focuses on the synthesis and physical properties of the viologen, the understanding of Stern-Volmer Kinetics, and the discussion of how each of the different quenchers had an effect on the fluorescence of the viologen.