Dual-Response Photofunctional Covalent Organic Framework for Acid Detection in Various Solutions

The detection of acid in different solution environments plays a significant role chemical, environmental and biological fields. However, reducing the constraints detecting environment, such as aqueous, organic solvents mixed phases aqueous phases, remains challenge. Herein, by combining N, N′, N′-tetrakis(4-aminophenyl)-1,4-phenylenediamine (TPBD) terephthalaldehyde (TA) via Shiff-base condensation, we constructed covalent framework (COF) TPBD-TA COF. COF exhibits color change from red to dark well fluorescence quenching with increase contents either or solvents, mixture due weak donor-acceptor interactions within proton ionization ability solutions. Therefore, regardless can realize dual-response limit low 0.4 μmol/L 58 nmol/L, respectively, protonation nitrogen atoms on imine bonds