Synthesis and Optical Properties of Novel Fluorescence‐Traced Benzimidazolium Bromides

Abstract

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 (λEmmax = 386–438 nm) with fluorescence quantum yields of 0.54 to 0.75 in aqueous solution.