Unexpected Deactivation of PdCl(cinnamyl)(NHC <sup>Cl</sup> ) Precatalysts Mediated by Alkylamines
Bibliographic record
Abstract
Chlorinating the backbone of N -heterocyclic carbene ligands (i.e., NHC Cl ) yielded Pd catalysts (i.e., Pd-NHC Cl ) with dramatically improved performance in cross-coupling catalysis. Unexpectedly, precatalysts of the type PdCl(cinnamyl)(NHC Cl ) at low catalytic loading (0.1 mol %) turned out to be not applicable in Buchwald-Hartwig C–N coupling with alkylamines. This is caused by the reaction of the precatalyst with alkylamines, leading to free NHC Cl and PdCl(cinnamyl)(alkylamine); similar reactivity was observed with ammonia. PdCl(cinnamyl)(alkylamine) is not activated to a zerovalent Pd species; therefore, catalysis cannot begin. Other precatalysts, like PdCl 2 (morpholine)(NHC Cl ) and PdCl 2 (3-chloropyridine)(NHC Cl ) (Pd-PEPPSI-NHC Cl ), as well as precatalysts of the type PdCl(cinnamyl)(NHC) bearing nonchlorinated ligands, are stable under these conditions, activated, and perform well in catalytic C–N coupling.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.002 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
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.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
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".