Multifunctional Logic Operations Based Upon Congruent Ion Sensing Appended with a Strategic Molecular Device: Spectroscopic Approach

Abstract A multi‐responsive smart molecular system is constructed using a newly synthesized Salen molecule, 1,3‐bis((E)‐2,3,4‐trimethoxy benzylideneamino) propan‐2‐ol (TMBP), to selectively recognize the presence and absence of Cu²⁺ ions aided by another selective metal ion, Zn²⁺. The emission efficiency of the non‐emissive probe is selectively and significantly enhanced in presence of Zn²⁺, while the improved emission of probe‐Zn²⁺ complex is completely quenched upon interaction with Cu²⁺. Thus, the probe acts as a reporter molecule for the selective detection of Cu²⁺ in the co‐presence of Zn²⁺. Comprehensive spectroscopic studies indicate that Zn²⁺ ion‐coordination significantly reduces the flexibility of the Schiff base unit and the extent of photoinduced electron transfer which in turn enhance the fluorescence intensity. While Cu²⁺, a d⁹ system, induces paramagnetic quenching over the enhanced emission through stable ground‐state complexation and metal‐ligand charge transfer. The spectroscopic results are translated into the designing of a multifunctional smart‐molecular system that could function as YES, NOT, INHIBIT, PASS 0, TRANSFER and NOT TRANSFER logic gates. Finally, a blueprint of a smart molecular device is proposed to present the relay sensing of Zn²⁺ and Cu²⁺ through logical outputs that would work in‐sync with the spectroscopic results.