Selective sensors for Zn2+ cations based on new green fluorescent poly(amidoamine) dendrimers peripherally modified with 1,8-naphthalimides

The paper reports on the spectral photophysical characteristics of two new fluorescent PAMAM dendrimers of zero and second generation decoreted with 1,8-naphthalimide units, designed for ionic detection. The dendrimers were studied by 1H NMR, 13C NMR, FT-IR spectroscopy and elemental analysis. Their ability to detect ions has been evaluated in acetonitrile by monitoring the quenching of the fluoresence intensity. Different ions have been tested: Zn2+, Co2+, Ni2+, Cu2+ and Fe3+ for the purpose. The results have shown clearly that only Zn2+ could be efficiently detected using the dendrimer of second generation. In addition, it has been shown that for both dendrimers in a acetonitrile–water solution, the fluoresence intensity is pH dependant, hence could find application as a detector of harmful pH changes in the environment.