Molecular mechanism of the metal-independent production of hydroxyl radicals by thiourea dioxide and H 2 O 2 .

Autor: Mao L; State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.; College of Resources and Environment, University of the Chinese Academy of Sciences, Beijing 100049, China., Quan Z; Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China., Liu ZS; State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.; College of Resources and Environment, University of the Chinese Academy of Sciences, Beijing 100049, China., Huang CH; State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.; College of Resources and Environment, University of the Chinese Academy of Sciences, Beijing 100049, China., Wang ZH; State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.; College of Resources and Environment, University of the Chinese Academy of Sciences, Beijing 100049, China., Tang TS; State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.; College of Resources and Environment, University of the Chinese Academy of Sciences, Beijing 100049, China., Li PL; State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.; College of Resources and Environment, University of the Chinese Academy of Sciences, Beijing 100049, China., Shao J; State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.; College of Resources and Environment, University of the Chinese Academy of Sciences, Beijing 100049, China., Liu YJ; Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China.; Center for Advanced Materials Research, College of Chemistry, Beijing Normal University, Zhuhai 519087, China., Zhu BZ; State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.; College of Resources and Environment, University of the Chinese Academy of Sciences, Beijing 100049, China.; State Key Laboratory of Chemical Resource Engineering, Department of Environmental Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
Jazyk: angličtina
Zdroj: Proceedings of the National Academy of Sciences of the United States of America [Proc Natl Acad Sci U S A] 2024 Apr 02; Vol. 121 (14), pp. e2302967120. Date of Electronic Publication: 2024 Mar 28.
DOI: 10.1073/pnas.2302967120
Abstrakt: It is well-known that highly reactive hydroxyl radicals (HO • ) can be produced by the classic Fenton system and our recently discovered haloquinone/H 2 O 2 system, but rarely from thiol-derivatives. Here, we found, unexpectedly, that HO • can be generated from H 2 O 2 and thiourea dioxide (TUO 2 ), a widely used and environmentally friendly bleaching agent. A carbon-centered radical and sulfite were detected and identified as the transient intermediates, and urea and sulfate as the final products, with the complementary application of electron spin-trapping, oxygen-18 isotope labeling coupled with HPLC/MS analysis. Density functional theory calculations were conducted to further elucidate the detailed pathways for HO • production. Taken together, we proposed that the molecular mechanism for HO • generation by TUO 2 /H 2 O 2 : TUO 2 tautomerizes from sulfinic acid into ketone isomer (TUO 2 -K) through proton transfer, then a nucleophilic addition of H 2 O 2 on the S atom of TUO 2 -K, forming a S-hydroperoxide intermediate TUO 2 -OOH, which dissociates homolytically to produce HO • . Our findings represent the first experimental and computational study on an unprecedented new molecular mechanism of HO • production from simple thiol-derived sulfinic acids, which may have broad chemical, environmental, and biomedical significance for future research on the application of the well-known bleaching agent and its analogs.
Competing Interests: Competing interests statement:The authors declare no competing interest.
Databáze: MEDLINE
Externí odkaz: