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Record W4413359994 · doi:10.1002/hlca.202500106

TEMPS, the Chalcogen Cousin of the Infamous Stable Radical TEMPO, Traps Radicals via Substitution on Its Dimer (TEMPS)<sub>2</sub>

2025· article· en· W4413359994 on OpenAlexafffund
Felix Englmaier, Luke A. Farmer, Derek A. Pratt

Bibliographic record

VenueHelvetica Chimica Acta · 2025
Typearticle
Languageen
FieldChemistry
TopicRadical Photochemical Reactions
Canadian institutionsUniversity of Ottawa
FundersNatural Sciences and Engineering Research Council of Canada
KeywordsChemistryChalcogenSubstitution (logic)RadicalDimerCousinPhotochemistryCrystallographyOrganic chemistry

Abstract

fetched live from OpenAlex

Abstract Nitroxides such as 2,2,6,6‐tetramethylpiperidin‐N‐oxyl (TEMPO) are the quintessential organic radicals. They are commonly used to trap alkyl radicals in controlled radical polymerizations, synthetic transformations and mechanistic experiments, and peroxyl radicals when applied as radical‐trapping antioxidants (RTAs). Relatively little is known about their sulfur analogs (N‐thiyl radicals, R2NS• and dithiobisamines, R2NS‐SNR2). We found that dithiobisamines of moderate steric bulk (including (TEMPS)2, the dimer of the sulfur analog of TEMPO), trapped peroxyl radicals with rate constants up to 1.2 × 106 m−1s−1 (at 100 °C) – similar to TEMPO. Unlike TEMPO, their radical‐trapping activity was not catalytic, independent of the rate of radical initiation and still operative in saturated hydrocarbons – implying a distinct mechanism. Additional experimental data and computations point to a homolytic substitution mechanism, analogous to that recently elucidated for tetrasulfides. In the absence of O2, alkyl radicals and dithiobisamines react to form sulfenamides, which may be exploited for synthetic purposes.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame machine prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Bench or experimental · Consensus signal: Bench or experimental
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.002
Threshold uncertainty score0.006

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.001
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0020.001

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.014
GPT teacher head0.246
Teacher spread0.232 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designBench or experimental
Domainnot available
GenreEmpirical

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

Quick stats

Citations0
Published2025
Admission routes2
Has abstractyes

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