Binaphthyl-derived salicylidene Schiff base for dual-channel sensing of Cu, Zn cations and integrated molecular logic gates

The 2,2′-bis(3,5-dichloro-2-hydroxybenzylideneamino)-1,1′-binaph thyl salen-type Schiff base (BCHB) has been synthesized and characterized. Exhibiting absorption and fluorescence changes in the presence of Cu²⁺ and Zn²⁺ in tetrahydrofuran (THF) solution, BCHB could be used as a colorimetric 'naked eye' and fluorescent chemosensor for the detection of Cu²⁺ and Zn²⁺ bi-functionally. Furthermore, this organic ligand can selectively recognize Cu²⁺ and Zn²⁺ in the presence of other metal ions (such as Na⁺, Ag⁺, Mn²⁺, Co²⁺, Ni²⁺, Fe³⁺, Cd²⁺, Hg²⁺, Pb²⁺, La³⁺, and Nd³⁺), respectively. On the other hand, BCHB presents a tunable system integrated with one OR logic gate as well as one INHIBIT logic gate with Zn²⁺ and Cu²⁺ as chemical inputs by monitoring fluorescence and absorbance as output signals. Also, one IMPLICATION gate operating in fluorescence mode with Cu²⁺ and EDTA as chemical inputs, based on their different binding capabilities, is present in this system.