A water-soluble carboxylic-functionalized chemosensor for detecting Al3+ in aqueous media and living cells: Experimental and theoretical studies

A new water-soluble carboxylic-functionalized chemosensor 1 was designed and synthesized. 1 exhibited the selective fluorescence enhancement toward aluminum ions with a 1:1 complexation stoichiometry in aqueous solution. The detection limit (24 nM) of 1 for Al3+ is about two order lower than the WHO guideline (7.41 μM) for the drinking water. 1 was successfully applied to living cells and real samples for detecting Al3+. Moreover, the sensing mechanism originated from the inhibited excited-state intramolecular proton transfer (ESIPT) process and the chelation-enhanced fluorescence (CHEF) effect, as supported by theoretical calculations.