Unconventional OFF-ON Response of a Mono(calix[4]arene)-Substituted BODIPY Sensor for Hg 2+ through Dimerization Reversion.

A new selective fluorogenic chemosensor for Hg 2+ , which combines a calixarene derivative with a BODIPY core as a fluorescent reporter, is described. The remarkable change in its fluorogenic properties in DMSO and CHCl 3 has been analyzed. A study of its spectral properties on dilution, along with molecular modeling studies, allowed us to explain that this behavior involves the formation of a J-dimer, as well as how the sensing mechanism of Hg 2+ proceeds.