A new generation of glutathione peroxidase enzyme mimic based on organotelluriumwas introduced. The catalytic cycles of these mimics, tellura and tellenol, were clari-fied by density functional theory and solvent-assisted proton exchange procedure asan indirect proton exchange chain. From the kinetic viewpoint, the oxidation oftellura (ΔG6¼= 23.55 kcal mol−1) was considered as the rate-determining step using asingle-step process. Various behaviors of tellenol were examined in the reduction oftellurenylsulfide based on methanethiol nucleophilicity. On the basis of the turnoverfrequency calculations, during the catalytic cycles of tellura and tellenol, the rate ofthe catalytic cycle of tellura is faster than that of tellenol. A decrease in the electrondensity and an increase in the Laplacian from the reactant to the transition states areevidence of the bond rupture, whereas an opposite change is evidence of the bondformation. Finally, different analyses of the electron location function and localizedorbital locator within the quantum theory of atoms in molecules were applied anddiscussed. The covalent nature of the intramolecular interactions suggests that theTe...N interaction is stronger than that of Te....H. Finally, based on different ana-lyses, tellura can be considered the more reactive GPx mimic than tellenol.

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