A new colorimetric chemosensor for Hg2+ based on coumarin azine derivative

A coumarin azine derivative: 3,3′-hydrazine-1,2-diylidenebis(methan-1-yl-1-ylidene)bis(7-(diethyl amino)-2H-chromen-2-one) (ligand 1) was synthesized and characterized. It was used as a colorimetric chemosensor for Hg2+. The absorption maximum of ligand 1 shows a large red shift from 490 nm to 565 nm (Δ = 75 nm) in the presence of Hg2+. The change in color is very easily observed by the naked eye, while other metal cations, such as Fe2+, Co2+, Ni2+, Zn2+, Cd2+, Cu2+, Fe3+, Ag+, Pb2+, alkali metal and alkaline earth metal cations do not induce such a change.