On NMR prediction of the effectiveness of p-phenylenediamine antioxidants

•NMR shift measurements and B3LYP calculations of para-phenylenediamine antioxidants.•Correlations between Molar Antioxidant Effectiveness (AEM) and NMR shifts.•Reverse trends for NMR shifts of both nitrogen atoms.•Possible AEM prediction based on NMR shifts. NMR shifts of N-phenyl-N′-alkyl-p-phenyl...

Full description

Saved in:
Bibliographic Details
Published in:Chemical physics letters 2015-10, Vol.639, p.78-82
Main Authors: Puškárová, Ingrid, Šoral, Michal, Breza, Martin
Format: Article
Language:English
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:•NMR shift measurements and B3LYP calculations of para-phenylenediamine antioxidants.•Correlations between Molar Antioxidant Effectiveness (AEM) and NMR shifts.•Reverse trends for NMR shifts of both nitrogen atoms.•Possible AEM prediction based on NMR shifts. NMR shifts of N-phenyl-N′-alkyl-p-phenylenediamines (PPD) in DMSO have been measured as well as evaluated by B3LYP calculations. According to Simon et al. Molar Antioxidant Effectiveness (AEM) of PPD antioxidants depends on the bond strength of hydrogens to amine nitrogens between aromatic rings (NA), to the side aliphatic chain nitrogens (NB) and to its neighboring tertiary carbon atoms (CT). AEM increases with NMR shifts of HA, HB, NA and probably also of CT atoms whereas NMR shifts of NB atoms exhibit a reverse trend. This is very surprising because similar reactions at A and B sites are supposed.
ISSN:0009-2614
1873-4448
DOI:10.1016/j.cplett.2015.09.013