Syntheses, Characterizations, and Properties of Electronically Perturbed 1,1‘-Dimethyl-2,2‘-bipyridinium Tetrafluoroborates

The syntheses of three new 2,2‘-bipyridinium tetrafluoroborate sensitizers are reported. Their preliminary
electrochemical and photophysical properties are compared to the properties of the more widely used
pyrylium cation sensitizers. In addition, the first examples of triplet−triplet absorption spectra of 2,2‘-bipyridinium ions are presented.