The radical scavenger activity of X1- and X2-substituted ethoxyquin derivatives has been investigated in the gas phase and water. The reaction enthalpies of radical scavenger activity of the studied derivatives have been calculated and compared with corresponding values of ethoxyquin. Results show that electron-withdrawing group substituents increase the bond disso- ciation enthalpy and ionization potential, while electron-donating group substituents cause a rise in the proton affinity. The ethoxyquin derivatives with the lowest bond dissociation enthalpy, ionization potential, and proton affinity values were identified as the compounds with high radical scavenger activity. Results show that the substituents in the X1 position have high potential for synthesis of novel ethoxyquin derivatives. Results show that ethoxyquin derivatives can process their protective role via hydrogen atom transfer and sequential proton loss electron transfer mechanisms in the gas phase and solvent, respectively. The calculated reaction enthalpies of the substituted ethoxyquins have linear dependences with Hammett con- stants and energy of the highest occupied molecular orbital that can be utilized in the selection of suitable substituents for the synthesis of novel radical scavengers based on ethoxyquin.
کلید واژگان :antioxidant, radical scavenger, ethoxyquin, substituent effect, DFT, EHOMO.
ارزش ریالی : 600000 ریال
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