Effect of Molecular Interactions on Electron-Transfer and Antioxidant Activity of Bis(alkanol)selenides: A Radiation Chemical Study

• Published in: Chemistry : a European journal Vol. 22; no. 34; pp. 12189 - 12198
• Main Authors: Kumar, Pavitra V., Singh, Beena G., Phadnis, Prasad P., Jain, Vimal K., Priyadarsini, K. Indira
• Format: Journal Article
• Language: English
• Published: Germany Blackwell Publishing Ltd 16.08.2016; Wiley Subscription Services, Inc
• Subjects: Alcohols - chemistry; Anti-inflammatory agents; Antioxidants; Antioxidants - chemistry; Cations; Cations - chemistry; Chains; Chemical compounds; Chemistry; Dimers; Electron Transport; Electrons; Formaldehyde; Hydroxyl Radical - chemistry; Inflammation; Molecular interactions; Organoselenium compounds; Organoselenium Compounds - chemistry; Pulse radiolysis; Pulse Radiolysis - methods; Quantum chemistry; Radiation; radical reactions; Radicals; Selenides; Selenium; Selenium compounds; selenoxides; Sulfur; Sulfur - chemistry; radical reactions; pulse radiolysis; selenides; selenoxides; antioxidants
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201601918

Understanding electron‐transfer processes is crucial for developing organoselenium compounds as antioxidants and anti‐inflammatory agents. To find new redox‐active selenium antioxidants, we have investigated one‐electron‐transfer reactions between hydroxyl (.OH) radical and three bis(alkanol)selenides (SeROH) of varying alkyl chain length, using nanosecond pulse radiolysis. .OH radical reacts with SeROH to form radical adduct, which is converted primarily into a dimer radical cation (>Se∴Se<)+ and α‐{bis(hydroxyl alkyl)}‐selenomethine radical along with a minor quantity of an intramolecularly stabilized radical cation. Some of these radicals have been subsequently converted to their corresponding selenoxide, and formaldehyde. Estimated yield of these products showed alkyl chain length dependency and correlated well with their antioxidant ability. Quantum chemical calculations suggested that compounds that formed more stable (>Se∴Se<)+, produced higher selenoxide and lower formaldehyde. Comparing these results with those for sulfur analogues confirmed for the first time the distinctive role of selenium in making such compounds better antioxidants. Roots radicals: Functionalized alkyl selenides react with hydroxyl radicals to form dimer radical cations, which are converted to selenoxides that are catalytically recycled by thiols. Comparing these results with those for sulfur analogues confirmed for the first time the distinctive role of selenium in making such compounds better antioxidants.