A Highly Selective 'On-Off-On' Optical Switch for Sequential Detection of Cu2+ and S2- Ions Based on 2, 6-Diformyl-4-methyl Phenol and Catecholase Activity by Its Copper Complex

摘要

A new highly selective chemosensor for Cu2+ and S2- ions, Ethyl 2-cyano-3-(2-hydroxy-5-methyl-3-(p-tolylimino)methyl)phenyl)acrylate) (HL) based on 2, 6-diformyl-4-methylphenol was designed and synthesized. The ligand exhibited excellent sensitivity towards copper ion by the emission quenching even in the presence of other biologically important metal ions. Once HL combine with Cu2+ it can display a rapid response and high selectivity toward sulfide anion resulting in off-on sensing via Cu2+ displacement assay. The signal transduction happen via reversible formation-separation of complex L-Cu and CuS and the complex L-Cu was synthesized by the reaction of HL and Cu2+ and characterized by single-crystal X-ray diffraction and DFT optimization studies. The catecholase like activity for L-Cu complex have been studied by using 3,5-di-tertbutylcatechol (3,5-DTBC) as the substrate.