AIEE active ionic liquid based on triphenyl amine functionalized Schiff base for the selective and sensitive detection of Sn2+ ion

A triphenylamine and imidazolium based fluorescent ionic liquid (IL) [TPA-SB][Br] was synthesized and its structure was elucidated using 1H, 13C NMR, FT-IR, UV-visible spectroscopy, and mass spectrometry. Furthermore, TGA and DSC studies were carried out to establish the thermal resilience of [TPA-SB][Br]. The novel molecule revealed distinct fluorescent recognition behavior for Sn2+ ions over eleven other transition metals in the solution phase. This encouraged us to devise a paper-based fluorescent sensor embed with [TPA-SB][Br]. The paper sensor also revealed outstanding sensing properties for Sn2+ ions. As a matter of fact, aggregation induced enhanced emission (AIEE) based fluorophores are extremely pivotal in devising fluorescent sensors. Interestingly, [TPA-SB][Br] exhibited remarkable 31.2 fold increase in fluorescence intensity for 5:95 ratio of THF:water, which reveals its exceptional AIEE characteristics. Notably, ours is the first report on a paper-based Sn2+ sensor based on fluorescent ionic liquid.