{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,28]],"date-time":"2026-10-28T12:56:03Z","timestamp":1793192163087,"version":"4.5.0"},"reference-count":16,"publisher":"National Academy of Sciences","issue":"10","content-domain":{"domain":["www.pnas.org"],"crossmark-restriction":true},"short-container-title":["Proc. Natl. Acad. Sci. U.S.A."],"published-print":{"date-parts":[[2007,3,6]]},"abstract":"\n The metal-independent decomposition of organic hydroperoxides and the formation of organic alkoxyl radicals in the absence or presence of halogenated quinones were studied with electron spin resonance (ESR) and the spin-trapping agent 5,5-dimethyl-1-pyrroline\n N<\/jats:italic>\n -oxide (DMPO). We found that 2,5-dichloro-1,4-benzoquinone (DCBQ) markedly enhanced the decomposition of\n tert<\/jats:italic>\n -butylhydroperoxide (\n t<\/jats:italic>\n -BuOOH), leading to the formation of the DMPO adducts with\n t<\/jats:italic>\n -butoxyl radicals (\n t<\/jats:italic>\n -BuO\n \u2022<\/jats:sup>\n ) and methyl radicals (\n \u2022<\/jats:sup>\n CH\n 3<\/jats:sub>\n ). The formation of DMPO\/\n t<\/jats:italic>\n -BuO\n \u2022<\/jats:sup>\n and DMPO\/\n \u2022<\/jats:sup>\n CH\n 3<\/jats:sub>\n was dose-dependent with respect to both DCBQ and\n t<\/jats:italic>\n -BuOOH and was not affected by iron- or copper-specific metal chelators. Comparison of the data obtained with DCBQ and\n t<\/jats:italic>\n -BuOOH with those obtained in a parallel study with ferrous iron and\n t<\/jats:italic>\n -BuOOH strongly suggested that\n t<\/jats:italic>\n -BuO\n \u2022<\/jats:sup>\n was produced by DCBQ and\n t<\/jats:italic>\n -BuOOH through a metal-independent mechanism. Other halogenated quinones were also found to enhance the decomposition of\n t<\/jats:italic>\n -BuOOH and other organic hydroperoxides such as cumene hydroperoxide, leading to the formation of the respective organic alkoxyl radicals in a metal-independent manner. Based on these data, we propose a mechanism for DCBQ-mediated\n t<\/jats:italic>\n -BuOOH decomposition and formation of\n t<\/jats:italic>\n -BuO\n \u2022<\/jats:sup>\n : a nucleophilic attack of\n t<\/jats:italic>\n -BuOOH on DCBQ, forming a chloro-\n t<\/jats:italic>\n -butylperoxyl-1,4-benzoquinone intermediate, which decomposes homolytically to produce\n t<\/jats:italic>\n -BuO\n \u2022<\/jats:sup>\n . This represents a mechanism of organic alkoxyl radical formation not requiring the involvement of redox-active transition metal ions.\n <\/jats:p>","DOI":"10.1073\/pnas.0605527104","type":"journal-article","created":{"date-parts":[[2007,3,1]],"date-time":"2007-03-01T06:29:21Z","timestamp":1172730561000},"page":"3698-3702","update-policy":"https:\/\/doi.org\/10.1073\/pnas.cm10313","source":"Crossref","is-referenced-by-count":79,"title":["Mechanism of metal-independent decomposition of organic hydroperoxides and formation of alkoxyl radicals by halogenated quinones"],"prefix":"10.1073","volume":"104","author":[{"given":"Ben-Zhan","family":"Zhu","sequence":"first","affiliation":[{"name":"*State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, People's Republic of China;"},{"name":"Linus Pauling Institute, Oregon State University, Corvallis, OR 97331; and"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hong-Tao","family":"Zhao","sequence":"additional","affiliation":[{"name":"Biophysics Research Institute, Medical College of Wisconsin, Milwaukee, WI 53226"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Balaraman","family":"Kalyanaraman","sequence":"additional","affiliation":[{"name":"Biophysics Research Institute, Medical College of Wisconsin, Milwaukee, WI 53226"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jun","family":"Liu","sequence":"additional","affiliation":[{"name":"*State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, People's Republic of China;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Guo-Qiang","family":"Shan","sequence":"additional","affiliation":[{"name":"*State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, People's Republic of China;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yu-Guo","family":"Du","sequence":"additional","affiliation":[{"name":"*State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, People's Republic of China;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Balz","family":"Frei","sequence":"additional","affiliation":[{"name":"Linus Pauling Institute, Oregon State University, Corvallis, OR 97331; 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