Rewritable security display material and Cl- sensor: Based on a bimetal competitive coordination controlled supramolecular gel

By rationally introducing Mg2+ and Co2+ into a supramolecular gel, a bimetal-gel MgCoG was prepared. MgCoG could reversibly fluorescent turn-on sense Cl- with specific selectivity under gel-gel states through competitive coordination of Mg2+ and Co2+ with gelators and Cl-. The MgCoG could act as Cl- test kit with high sensitivity and selectivity. The detection limit of the fluorescence spectra was 1.0 x 10(-6) M (1 mu M) for Cl- anion. In addition, the MgCoG could act as rewritable security display material, when writing on the MgCoG film with a writing brush dipped in Cl- water solution, a brilliant blue fluorescent writing image appeared. This fluorescent image could be erased by brushing Co2+ on the film again. (c) 2014 Elsevier B.V. All rights reserved.