From yellow to pink using a fluorimetric and colorimetric pyrene derivative and mercury (II) ions

Abstract

A new simple and multifunctional fluorescent probe based on pyrene linked through an imine bond to a hydroxyphenol unit was synthesised, fully characterized and investigated in solution. Additionally, its behaviour in the presence of several ions (H+, Zn2+, Cd2+, Cu2+, Ni2+, Pb2+, Fe2+, Hg2+ and Al3+) was investigated in CH2Cl2. It was found that the absorption spectra of probe 1 shows no differences for all ions titrations except in the presence of H+ and Hg2+ where a new longer wavelength band becomes visible (inducing a colour change from yellow to orange and pink, respectively). In the emission, a blue-shift and an enhancement of the fluorescence of the probe for all metal ions was observed with the exception of Al3+ where no detectable changes could be observed. The probe was found to be selective for Hg2+ ion at low concentrations (till one equivalent).