Sensors for detecting metal ions and protons based on new green fluorescent poly(amidoamine) dendrimers peripherally modified with 1,8-naphthalimides

Two recently synthesized poly(amidoamine) dendrimers from zero and second generation whose periphery comprises fluorescent 4-piperidino-1,8-naphthalimide units have been investigated as potential sensors of metal cations and protons. The photophysical characteristics of the dendrimers have been determined by fluorescence and absorption spectroscopy. Experiments have been performed in the presence of Zn2+, Ni2+, Ce3+, Cu2+, Co2+ and Ag+ cations. The increase in the fluorescence intensity of the dendrimers in the presence of protons indicates their sensitivity to the protons. The response of the dendrimers ligands depends on the nature of the added metal cations. The best performance is accomplished for detecting Cu2+ and Co2+ cations. The results obtained reveal the capacities of these systems to act as reliable detectors of environment pollution by metal cations and protons.