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 2+ , K + , Ca 2+ , Cu 2+ , Zn 2+ , Pb 2+ , Ag + , Cd 2+ and Fe 3+ on the fluorescence of these COFs. The results show that only Fe 3+ significantly quenched the fluorescence of the studied COFs. The possibility of the four COFs for selective sensing of Fe 3+ was demonstrated. The possible mechanism of the effect of Fe 3+ on the fluorescence of the COFs was based on the absorption competition quenching.