Efficient quenching of the fluorescence of binaphthyl-based amphiphiles by mercury(II) complexes

The studies of fluorescence quenching by mercury(II) anionic complexes in assemblies of fluorescent binaphthyl-based amphiphiles are reported. The partition equilibria of mercury(II) complexes between aggregate pseudophase and aqueous solution have been investigated. The partition model was proposed and partition constants of anionic iodide complexes of Hg(II) were calculated. The efficient quenching effect of HgI2−4 was explained by long-range Förster energy transfer, whereas quenching by other anionic complexes (HgBr2−4 and Hg(S2O3)2−2) was attributed to the collisional process described by Stern-Volmer kinetics. An analytical potential of the Hg(II)/iodide-binaphthyl amphiphile system, allowing Hg(II) detection at 10−7–10−8 M, was also discussed, and a procedure for selective trace mercury determination in water was proposed and tested.