Ratiometric detection of Hg2+ ions: an allosterically synchronized Hg2+/Li+ switch based on thiacalix[4]crown

A new heteroditopic chemosensor based on the 1,3-alternate conformation of thiacalix[4]crown shows a ratiometric fluorescence response towards Hg2+ ions. Further, a negative allosteric behaviour between Hg2+/Li+ ions is observed. Thus, metal ion exchange triggers a Hg2+/Li+ switchable fluorescent chemosensor.