Exploring fluorescent covalent organic frameworks for selective sensing of Fe3+

Covalent organic frameworks（COFs） have been widely applied in gas capture and separation, but the fluorescent property of COFs with large π-conjugated system tends to be underexplored. Here we report the fluorescent properties of several COFs including TaTa, DhaTab, TRITER-1 and TzDa and the effect of metal ions of Na+, Mg;, K+, Ca;, Cu;, Zn;, Pb;, Ag+, Cd;and Fe;on the fluorescence of these COFs. The results show that only Fe;significantly quenched the fluorescence of the studied COFs. The possibility of the four COFs for selective sensing of Fe;was demonstrated. The possible mechanism of the effect of Fe;on the fluorescence of the COFs was based on the absorption competition quenching.