Two highly sensitive Schiff-base fluorescent indicators for the detection of Zn2+

摘要

Two novel Schiff-based fluorescent probes 1 and 2 for Zn2+ ion were developed. The spectroscopic behavior toward metal ions has been investigated by the absorption and fluorescence method. Both of the two probes were found to show good selectivity to Zn2+ ion over other metal ions in ethanola€“water solution, such as Li+, Na+, Mg2+, Al3+, K+, Ca2+, Ba2+, Cr3+, Mn2+, Cu2+, Co2+, Ni2+, Fe3+, Hg2+, Ag+, Cd2+ and Pb2+. The selectivity mechanism of 1 and 2 to metal ions is based on a combinational effect of proton transfer (ESPT), CN isomerization and chelation-enhanced fluorescence (CHEF). pH response experiments show that the probes can be used to indicate pH values under certain conditions.