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Substituent effects on the antioxidant capacity of monosubstituted diphenylamines: a DFT study
Author(s) -
Thao Pham Thi Thu,
Thong Nguyen Minh,
Vo Quan V.,
Van Bay Mai,
Quang Duong Tuan,
Nam Pham Cam
Publication year - 2020
Publication title -
vietnam journal of chemistry
Language(s) - English
Resource type - Journals
eISSN - 2572-8288
pISSN - 0866-7144
DOI - 10.1002/vjch.202000065
Subject(s) - substituent , antioxidant capacity , antioxidant , chemistry , computational chemistry , medicinal chemistry , organic chemistry
There are undesirable effects leading to considerable changes in the properties of polymers and plastics since exposing to oxygen undergo oxidative degradation. Therefore, investigation of the bond dissociation enthalpies (BDEs) of N‐H bond for a series of monosubstituted diphenylamines is great interest. In this study, DFT‐based method B3P86/6‐311G was employed to perform this task. In comparison with the available experimental data, this method could reproduce the BDE(N‐H)s values more accuracy. Effects of substituents and substitution positions on the BDE(N‐H)s were also examined. Moreover, there is a good correlation of BDE(N‐H)s with the Hammett's substituent constants. Depending on the nature of substituents, electron withdrawing groups increase the BDE(N‐H)s but electron donating ones reduce the BDE(N‐H)s. The hydrogen atom transfer processes from N‐H bond of these diphenylamines to the peroxyl radical (CH 3 OO • ) were also analyzed via potential energy surfaces and kinetic calculations.