Observing elusive tetroxides in gas-phase radical reactions supports the Russell mechanism.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41824568.
- Also identified by DOI 10.1126/sciadv.aeb6495 and PMC identifier 12985734.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Organic peroxy radicals (RO<sub>2</sub>) are important intermediates for oxidation processes in aerobic chemical systems. Their self- and "cross"-reactions (i.e., with themselves and other RO<sub>2</sub>) are increasingly receiving attention in a wide range of applications, from atmospheric chemistry to cancer therapies. However, their mechanism has been debated for decades. The Russell mechanism, widely assumed for these reactions today, is characterized by a tetroxide intermediate, only observed once and partially since its postulate in 1957. Here we report the observation of tetroxides in the gas-phase reactions of different RO<sub>2</sub> by direct mass spectrometry, in which ionic and gas-phase dimerization could be ruled out. Within the uncertainties in the kinetic profiles, the lifetime for CH<sub>3</sub>OOOOCH<sub>3</sub> was determined to be in the range 0.2 and 200 milliseconds, consistent with an intermediate and supporting the Russell mechanism.