Triazolopyridines. Part 28. The ring–chain isomerization strategy: triazolopyridine- and triazoloquinoline–pyridine based fluorescence ligands

The ring–chain isomerization of [1,2,3]triazolo[1,5-a]pyridines or [1,2,3]triazolo[1,5-a] quinolines has been efficiently employed as a tool to provide tridentate fluorescent structures. Based on these scaffolds, a new family of highly fluorescent compounds has been synthesized and evaluated for the recognition of zinc or copper cations. In addition, the 1:1 Zn+2-L complex of a naphthalene triazolopyridine–pyridine derivative revealed high efficiency as sensor for anions providing large binding constants for nitrite and cyanide.