Reaction of group 16 analogues of ethoxyquin with hydrogen peroxide: A computational study

Analogues of the antioxidant ethoxyquin are studied to determine the effects of changing the group 16 element in the reacting center of a glutathione peroxidase mimic. The energy barrier for hydrogen peroxide reduction decreases along the group, with sulfur showing the highest, selenium intermediate, and tellurium the lowest barrier. The ethyl side chain on the chalcogen is substituted with methyl and tertiary-butyl groups to determine the degree of steric effects on the barrier. A phenyl substituent results in a higher barrier than the alkyl side chains.