Iridium Diphosphine Complexes Featuring Pendant Lewis Acids: Efforts toward Selective Heteroarene Borylation
Bibliographic record
Abstract
Abstract The selective forging of carbon‐boron bonds via C−H borylation stands as a central means to access fine chemical precursors. Notwithstanding, achieving selectivity in this reaction is difficult, calling for the design of molecular catalysts that offer a vector for mechanistic control. This report aims to achieve such through the strategic placement of Lewis acids in the ligand periphery, permitting engagement with a substrate through non‐covalent Lewis acid/base interactions. Various diphosphine iridium(I/III) complexes having 1,2‐bis(di‐n‐propylphosphino)ethane) (dnppe), tetrakisallylphosphinoethane (tape) and 1,2‐bis(di(3‐dicyclohexylboranyl)propylphosphino)ethane (P2BCy4) ligands were prepared. The P2BCy4 ligand scaffold boasts four Lewis acidic boron groups in its secondary coordination sphere, which are shown to engage with N‐heterocycles, tape is the precursor to P2BCy4, and dnppe is a saturated n‐propyl analogue devoid of boron functionality. Select combinations of such iridium salts/diphosphine ligands were assayed in the catalytic borylation of 2‐methylpyridine using B2Pin2 (Pin=pinacol).
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot 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.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| 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 source (direct Gemma or distilled Codex), 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".