Salicylimine-based fluorescent chemosensor for magnesium ions in aqueous solution

A new fluorescent schiff base chemosensor (H2L) was prepared for the sensitive and selective sensing of Mg2+ ions based on multiple mechanisms. H2L is a weak fluorescent (f = 0.031) due to PET process and C=N isomerization. Upon addition of Mg2+, the complex [MgL] was formed and a remarkable fluorescence enhancement (f = 0.182) was produced. H2L had no such significant effect on the fluorescence in the presence of metal ions, such as Na+, Ag+, K+, Ca2+, Mg2+, Hg2+, Mn2+, Co2+, Ni-2(+), Cu2+, Zn2+, Cd2+, Pb2+, Cr-3(+), Fe3+, and In3+. The satisfactory linear relationship was observed between the added concentrations of Mg2+ and the fluorescence intensity of H2L. The detection limit was 3.04 x 10(-9) M with a rapid response time. Chemical inputs of Mg2+ and Fe3+ ions satisfy the conditions of INHIBIT molecular logic gate.