DFT and Experimental Study of the Host–Guest Interactions Effect on the Structure, Properties, and Electro-Catalytic Activities of N₂O₂–Ni(II) Schiff-Base Complexes Incorporated into Zeolite

Ni^II-(<i>N</i>,<i>N</i>′-bis­(2,4-dihydroxyacetophenone)-2,2-dimethylpropandiimine (Ni^II{salnptn­(4-OH)₂}) complex has been encapsulated within the supercage of zeolite-NaY by reacting Ni²⁺-exchanged NaY with the flexible Schiff-base ligand that diffuses into the cavities. The encapsulated complex is characterized by EDX, scanning electron microscopy, powder X-ray diffraction, FT-IR, and cyclic voltammetry studies. Density functional calculation is being carried out on both the free nickel Schiff-base complex and that encapsulated in NaY zeolite to investigate changes in structural parameters, energies of the HOMO and LUMO, and absolute hardness and softness. Electrochemical properties of the NaY zeolite-encapsulated Ni^II{salnptn­(4-OH)₂}-modified carbon paste electrode and the Pt electrode modified with the film derived from the electro-polymerization of this complex are studied. These modified electrodes show electro-catalytic activity toward the oxidation of methanol and other short-chain aliphatic alcohols. The results show two different oxidation mechanisms on the surface of these modified electrodes. The effect of some parameters such as potential scan rate, concentration of alcohols, and the corresponding rate laws have been derived. Furthermore, the rate constants for the catalytic reaction (<i>k</i>′) of alcohols are obtained