Hyperbranched polyyne containing naphthalimide moiety as a fluorescent chemosensor for mercury ion

Abstract

The development of multidimentional conjugated polymers as fluorescent sensor has been extremely attractive for detecting toxic ion in trace level. In this paper, a new hyperbranched polyyne with polytris(4-ethynylphenyl)amine (PTEPA) as the core, benzoyl thiourea-naphthalimide (NAP) as Hg (II) detected unit was designed and synthesized. The addition of Hg (II) ion transforms the thiourea unit of the chemodosimeter under THF conditions into an imidazoline moiety that is a much less electron-donating group, and hence results in a reduction in electron delocalization within the fluorophore. The emission maximum exhibits blue-shift and increase of fluorescent intensity. To confirm selectivity of the sensor towards mercury ions, it was also titrated with other divalent metal ions. No significant change was observed in the fluorescence spectra.

Keywords

polytris(4-ethynylphenyl)amines / naphthalimide / fluorescent sensor / mercury ion