scholarly journals Electronic and Hydrogen Bonding Effects on the Chain-Breaking Activity of Sulfur-Containing Phenolic Antioxidants

2006 ◽  
Vol 71 (17) ◽  
pp. 6325-6332 ◽  
Author(s):  
Riccardo Amorati ◽  
Maria Grazia Fumo ◽  
Stefano Menichetti ◽  
Veronica Mugnaini ◽  
Gian Franco Pedulli
Keyword(s):  
Hydrogen Bonding ◽  
Phenolic Antioxidants ◽  
Chain Breaking ◽  
Sulfur Containing

Supramolecular cooperative interaction-induced assembly of phosphotungstate polyanions and sulfur-containing pyridine-based cations

CrystEngComm ◽  
2018 ◽  
Vol 20 (11) ◽  
pp. 1588-1596 ◽  
Author(s):  
Xuerui Tian ◽  
Xing Xin ◽  
Yuanzhe Gao ◽  
Zhangang Han
Keyword(s):  
Hydrogen Bonding ◽  
Cooperative Interaction ◽  
Supramolecular Interactions ◽  
Sulfur Containing

Three crystals were assembled by means of multiple weak intermolecular cooperative supramolecular interactions of hydrogen bonding, S⋯O, C–H⋯π, and polyanion–π.

The antioxidant activities of phenolic antioxidants in free radical peroxidation of phospholipid membranes

1990 ◽  
Vol 68 (12) ◽  
pp. 2258-2269 ◽  
Author(s):  
Lawrence Ross Coates Barclay ◽  
Kimberly Ann Baskin ◽  
Kelly Andrea Dakin ◽  
Steven Jefffrey Locke ◽  
Melinda Ruth Vinqvist
Keyword(s):  
Hydrogen Bonding ◽  
Free Radical ◽  
Rate Constants ◽  
Antioxidant Activities ◽  
Hydrogen Abstraction ◽  
Peroxyl Radicals ◽  
Phenolic Antioxidants ◽  
Inhibition Rate ◽  
Radical Chain ◽  
Tert Butyl

Autoxidation of dilinoleoylphosphatidylcholine (DLPC) bilayers photoinitiated by benzophenone takes place by a free radical chain mechanism according to product studies of the cis, trans and trans, trans-9- and -13-linoleate hydroperoxides formed and kinetic studies of the reaction order as a function of light intensity. The absolute rate constant for hydrogen abstraction from DLPC bilayers by peroxyl radicals is found to be 36.1 M−1 s−1 at 37 °C. Preliminary measurements of activities of phenolic antioxidants, α-tocopherol (α-T), 2,2,5,7,8-pentamethyl-6-hydroxychroman (PMHC), 2,5,7,8-tetramethyl-6-hydroxychroman-2-carboxylate (Trolox), and 2,6-di-tert-butyl-4-methylphenol (BHT) by oxygen uptake studies during inhibition periods using photoinitiation gave uncorrected inhibition rate constants, Kinh, for α-T, PMHC, and Trolox several orders of magnitude lower than observed earlier in chlorobenzene. Three series of phenolic antioxidants, (a) polyalkyl-6-hydroxychromans, (b) polyalkyl-4-methoxyphenols, and (c) trialkylphenols, were examined for their antioxidant activities in DLPC membranes during thermally initiated autoxidation by azobis-2,4-dimethylvaleronitrile (DMVN). The corrected inhibition rate constants, kinh, observed in (a), α-T (5.8 × 103), PMHC (17.8 × 103), Trolox (5.8 × 103), 2,2-dimethyl-5,7-diisopropyl-6-hydroxychroman, 4a (55 × 103), and 2,2,5-trimethyl-7-tert-butyl-6-hydroxychroman, 5a (61 × 103) M−1 s−1, are dramatically lower, by several orders of magnitude, than those measured earlier in chlorobenzene and significantly lower (about 1/40–1/10) than those measured in solution in tert-butyl alcohol and less than kinh measurements (1/2–1/5) in aqueous SDS micelles. The kinh values for series (b) were 2,3,5,6-tetramethyl-4-methoxyphenol (TTMMP) (2.1 × 103), 2,3,6-trimethyl-4-methoxyphenol (TMMP) (10.4 × 103), and 2,6-di-tert-butyl-4-methoxyphenol (DBHA) (27.5 × 103) M−1 s−1 and for (c) were 2,6-di-tert-butyl-4-methylphenol (BHT) (3.7 × 103) and 2,4,6-trimethylphenol (TMP) (0.56 × 103) M−1 s−1. The results show an overall leveling and depression of antioxidant activities in DLPC membranes in the series (a), (b), (c) compared to those reported in solution in chlorobenzene, where large differences were attributed to steroelectronic effects of the para ether oxygen stabilizing the derived phenoxyl radicals in (a) and (b) types. The results in aqueous micellar and membrane systems are interpreted in terms of polar solvation effects. Hydrogen bonding by water at both the ether and phenolic groups decreases the activity of the (a) series. Hydrogen bonding at the phenolic hydroxyl appears to be the more significant factor since steric hindrance to H-bonding at hydroxyl allows 4a and 5a to be the most active antioxidants of the α-tocopherol series (a) and DBHA to be the most active antioxidant of the (b) series. Keywords: antioxidant activities, phenols, membranes, peroxidation, kinetics.

Some aspects of a new class of sulfur containing phenolic antioxidants

1995 ◽  
Vol 49 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Hansrudolf Meier ◽  
Paul Dubs ◽  
Hanspeter Künzi ◽  
Roger Martin ◽  
Gerrit Knobloch ◽  
...  
Keyword(s):  
Phenolic Antioxidants ◽  
New Class ◽  
Sulfur Containing

Reactions of Sulfur Containing Phenolic Antioxidants for Elastomers

1999 ◽  
Vol 153 (1) ◽  
pp. 275-300 ◽  
Author(s):  
Hansrudolf Meier ◽  
Hanspeter Kuenzi ◽  
Gerrit Knobloch ◽  
Guenther Rist ◽  
Martin Szelagiewicz
Keyword(s):  
Phenolic Antioxidants ◽  
Sulfur Containing

Radical Chain Breaking Bis( ortho ‐organoselenium) Substituted Phenolic Antioxidants

2021 ◽  
Vol 16 (8) ◽  
pp. 966-973
Author(s):  
Aditya Upadhyay ◽  
Bhagat Singh Bhakuni ◽  
Rahul Meena ◽  
Sangit Kumar
Keyword(s):  
Phenolic Antioxidants ◽  
Radical Chain ◽  
Chain Breaking
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