A colorimetric chemosensor for the sequential recognition of Mercury (II) and iodide in aqueous media

Abstract A new highly selective colorimetric chemosensor 1 N′1,N′2-bis((1E,2E)-3-(4-(dimethylamino)phenyl)allylidene)oxalohydrazide was designed and synthesized as a colorimetric sensor for Hg 2 + . The sensor 1 showed high selectivity toward Hg 2 + in a 1:1 stoichiometric system and fast color change from yellow to orange in the presence of Hg 2 + . The sensing mechanism was explained by theoretical calculations. Moreover, the resulting 1 -Hg 2 + complex acted as an efficient colorimetric sensor for I − , showing recovery of 1 from 1 -Hg 2 + complex. Furthermore, 1 and 1 -Hg 2 + complex could be used as practical, visible colorimetric test kits for Hg 2 + and I − , respectively, in an aqueous environment. Therefore, probe 1 could be a good alternative method for onsite and real time screening of Hg 2 + and I − .