Experimental and computational investigation of highly selective dual-channel chemosensor for Al(III) and Zn(II) ions: construction of logic gates

The N, $$\hbox {N}^\prime $$ -Bis(salicylidene)-2-hydroxy-phenylmethanediamine (BSHPMD) was synthesized and characterized by IR, UV-Vis and $$^{1} \hbox {H}$$ NMR spectroscopic techniques. The single crystal X-ray diffraction studies reveal that the compound had a monoclinic crystal system with C2/c space group. The cation recognizing profile of the receptor BSHPMD was explored by UV-Vis and fluorescence spectroscopic methods. The receptor was found to recognize selectively $$\hbox {Al}^{3+}$$ and $$\hbox {Zn}^{2+}$$ ions over a panel of other metal ions such as $$\hbox {Na}^{+}$$ , $$\hbox {Mg}^{2+}$$ , $$\hbox {Ca}^{2+}$$ , $$\hbox {Mn}^{2+}$$ , $$\hbox {Co}^{2+}$$ , $$\hbox {Ni}^{2+}$$ , $$\hbox {Cu}^{2+}$$ , $$\hbox {Sr}^{2+}$$ , $$\hbox {Cd}^{2+}$$ , $$\hbox {Ba}^{2+}$$ , $$\hbox {Hg}^{2+}$$ and $$\hbox {Pb}^{2+}$$ . The Job’s plot analysis reveals that BSHPMD binds with $$\hbox {Al}^{3+}$$ and $$\hbox {Zn}^{2+}$$ in 1:1 stoichiometry ratio. The binding constants of the receptor for $$\hbox {Al}^{3+}$$ and $$\hbox {Zn}^{2+}$$ were $$2.13 \times 10^{3}$$ and $$16.23 \times 10^{3} \hbox {M}^{-1}$$ , respectively. The detection limit for $$\hbox {Al}^{3+}$$ and $$\hbox {Zn}^{2+}$$ is $$10.04 \times 10^{-8}$$ and $$4.98 \times 10^{-8} \, \hbox {M}$$ , respectively. The NMR titration and IR titration studies reveal the sensing mechanism of BSHPMD. The multi-ion detection of BSHPMD is used to construct NAND and OR molecular logic gates. Hirshfeld surface analysis based on DFT method with 3-21G as basis set is used to calculate various intermolecular interactions. Fingerprint plots are made to find out the percentage of different types of interactions. SYNOPSIS We synthesized salicylaldehyde-based Schiff base sensor by facile condensation of easily available and inexpensive chemicals. The structure was established by single-crystal XRD study, Hirshfeld surfaces and fingerprint analysis. The compound can be used as a sensor for detecting $$\hbox {Al}^{3+}$$ and $$\hbox {Zn}^{2+}$$ ions selectively. The Schiff base sensor was found to be active even in the presence of many other metal ions. Intramolecular interactions existing in the Schiff base were calculated by DFT method. The multi-ion detection was used to construct NAND and OR Molecular logic gates.