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Phenolic compounds undergo radical coupling under oxidizing conditions. Silicone oils were modified with eugenol using hydrosilylation to create oils and elastomers that exhibited antioxidant activity due to the presence of phenols, as shown by DPPH and other oxidative assays. At room temperature, phenolic coupling was not observed, as judged by lack of changes in viscosity or formation of gels. By contrast, peroxide oxidants at temperatures above 90 °C led to crosslinked materials whose physical properties (related to crosslink density) correlated with eugenol content, equivalents of peroxide added and reaction time. The product elastomers were also efficient antioxidants, although there was some attenuation of activity in higher crosslinked materials, consistent with diverse radical recombination processes. [ABSTRACT FROM AUTHOR]

Antioxidants are important mediators of radical processes. Nature exploits a variety of antioxidants, including vitamins, to moderate oxidation in living systems. Silicone oils and elastomers, widely used in personal care and biomedical applications, are rather unreactive under redox conditions and can therefore host such reactions. We report that phenolic antioxidants, including derivatives of vitamins A and E, and eugenol are readily tethered to silicone oils. These natural constituents dilute the energetic toll required to make silicones while delivering antioxidant properties to the product silicone oils. [ABSTRACT FROM AUTHOR]

The viability of pathogens at interfaces can be disrupted by the presence of (cationic) charge and chelating groups. We report on the synthesis of silicone dendrimers and linear polymers based on a motif of hexadentate ligands with the ability to capture and deliver metal ions. Mono-, di- or trialkoxysilanes are converted in G1 to analogous vinylsilicones and then, iteratively using the Piers-Rubinsztajn reaction and hydrosilylation, each vinyl group is transformed into a trivinyl cluster at G2. The thiol-ene reaction with cysteamine or 3-mercaptopropionic acid and the trivinyl cluster leads to hexadentate ligands 3 × N–S or 3 × HOOC–S. The compounds were shown to effectively capture a variety of metals ions. Copper ion chelation was pursued in more detail, because of its toxicity. On average, metal ions form chelates with 2.4 of the three ligands in a cluster. Upon chelation, viscous oils are converted to (very) soft elastomers. Most of the ions could be stripped from the elastomers using aqueous EDTA solutions, demonstrating the ability of the silicones to both sequester and deliver ions. However, complete ion removal is not observed; at equilibrium, the silicones remain ionically crosslinked. [ABSTRACT FROM AUTHOR]