Synthesis and optical properties of novel fluorescence-traced benzimidazolium bromides

Article abstract of DOI:10.1002/jhet.1819

Seven novel fluorescence-traced 1-aryl-2-substituted-3-allyl-1H- benzimidazolium bromides (5a, 5b, 5c, 5d, 5e, 5f, 5g) were synthesized by alkylation and quaternization of compounds 1-aryl-2-substituted-1H- benzimidazoles (4a, 4b, 4c, 4d, 4e, 4f, 4g) with excess allyl bromide in acetonitrile at refluxing temperature. Their structures were characterized by ¹H-NMR, MS, and elemental analysis. They emit violet-blue light (λ^Em_max = 386-438 nm) with fluorescence quantum yields of 0.54 to 0.75 in aqueous solution.