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

A multi‐responsive smart molecular system was constructed on a newly synthesized Salen molecule, 1,3‐bis((E)‐2,3,4‐trimethoxy benzylideneamino) propan‐2‐ol (TMBP) to selectively validate the presence as well as the absence of Cu2+ dictated by another selective metal ion, Zn2+. The emission efficiency of the non‐emissive probe was significantly enhanced by Zn2+ selectively, while specific binding of the probe‐Zn2+ complex with Cu2+ completely quenched the enhanced emission. Thus, the probe acted as a reporter molecule for the selective detection of Cu2+ in the co‐presence of Zn2+. Comprehensive spectroscopic studies indicated that Zn2+ ion‐coordination significantly reduced the flexibility of the Schiff base unit and decreased the extent of photoinduced electron transfer (PET) enabling an enhancement of fluorescence intensity. While, Cu2+, a d9 system, induced paramagnetic quenching through formation of a stable ground‐state complex as established from the UV‐Vis analysis and time resolved fluorescence measurements. The spectroscopic results were implemented into the designing of a multifunctional molecular logic system that could function as YES, NOT, INHIBIT, PASS 0, TRANSFER and NOT TRANSFER logic gates. Finally, a blueprint of a smart molecular device was proposed to present the relay sensing of Zn2+ and Cu2+ through logical outputs that would work in‐sync with the spectroscopic results.