1,3-Dipolar cycloaddition of alkynes to azides. Construction of operationally functional metal responsive fluorophores

The copper catalyzed 1,3-dipolar cycloaddition of 4-butoxyphenylazide with 2-, 3- or 4-ethynylpyridine furnishes 1,4-diaryltriazoles, which display turn-on fluorescence upon addition of metal cations.