Multi-signaling detection of Hg2+ and Cu2+ by a ferrocene–pyrazole dyad associated with molecular-scale arithmetic

Ferrocene-based sensor R was synthesized and characterized by spectroscopic methods. The optical, electrochemical and cation-sensing properties of receptor R are presented. Receptor R behaves as a selective multi-channel signaling chemosensor molecule for Hg2+ and Cu2+ ions in CH3CN. The binding mode of Hg2+ with R was determined by 13C NMR titration. Both optical and electrochemical methods were applied for the detection of cations in water sample. The characteristic fluorescence of R with the Cu2+ selective ON–OFF and the Hg2+ selective fluorescence bathochromic shift can be observed and the concept has been used to construct a combinational logic circuit at the molecular level.