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Record W3198377927 · doi:10.26434/chemrxiv.13058024.v1

Method to Predict Reagents in Iridium-Based Photoredox Catalysis

2020· preprint· en· W3198377927 on OpenAlexaff
Antoine Juneau, Taylor O. Hope, Jason Malenfant, Mihai Mesko, Jacob A. Mcneill, Mathieu Frenette

Bibliographic record

VenueChemRxiv · 2020
Typepreprint
Languageen
FieldChemistry
TopicRadical Photochemical Reactions
Canadian institutionsUniversité du Québec à Montréal
Fundersnot available
KeywordsReagentChemistryElectron transferReactivity (psychology)Reaction rate constantCatalysisOxidizing agentPhotochemistryPhotoredox catalysisAcetonitrileExcited statePhotocatalysisKineticsPhysical chemistryOrganic chemistry

Abstract

fetched live from OpenAlex

Visible-light photoredox catalysts with oxidizing excited states have been broadly applied in organic synthesis. Following photon absorption by the photocatalyst, electron transfer from an organic reagent is the most common mechanistic outcome for this class of reaction. Reduction potentials for organic reagents are therefore useful to predict reactivity and DFT proved to be useful as a predictive tool in this regard. Due to the complex mechanisms that follow electron transfer, kinetics play a crucial role in the success of photoredox reactions. We extend the predictive tools of DFT to estimate the electron transfer rates between an excited photocatalyst and various organic substrates. To calibrate our model, 49 electron transfer rate constants were experimentally measured in acetonitrile for the catalyst Ir[dF(CF 3 )ppy] 2 (dtbpy) + . The rate constants, k q , gave a clear predictive trend when compared to calculated ionization energies in “frozen solvent”, which was a better predictor than standard reduction potentials in our case. The calculated k q gave an average error of 17% for log(k q ) values between 4 and 11. This simple method can predict the reactivity of hundreds of reagents in silico . Notably, the calculations offered unexpected insight that we could translate into success for the C-H activation of acetylacetone as a proof-of-concept.

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)0.001
metaresearch head score (Gemma)0.002
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Simulation or modeling · Consensus signal: Simulation or modeling
GenreCandidate signal: Methods · Consensus signal: Methods
Teacher disagreement score0.003
Threshold uncertainty score0.012

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0010.002
Meta-epidemiology (narrow)0.0010.000
Meta-epidemiology (broad)0.0010.000
Bibliometrics0.0010.001
Science and technology studies0.0000.000
Scholarly communication0.0010.001
Open science0.0010.000
Research integrity0.0010.001
Insufficient payload (model declined to judge)0.0030.001

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 head0.032
GPT teacher head0.314
Teacher spread0.282 · 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 designSimulation or modeling
Domainnot available
GenreMethods

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

Citations1
Published2020
Admission routes1
Has abstractyes

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