Electrophilic Aromatic Substitution Reactions of a Tungsten-Coordinated Phosphirenyl Triflate
Bibliographic record
Abstract
The phosphirenyl cation complex [W(CO) 5 {PC(Ph)C(Ph)}] + ( 2 ) is formed by chloride abstraction from the chlorophosphirene complex [W(CO) 5 {P(Cl)C(Ph)C(Ph)}] ( 1 ) with excess AlCl 3 . The phosphirenyl triflate complex [W(CO) 5 {P(OSO 2 CF 3 )C(Ph)C(Ph)}] ( 3 ) is formed by reaction of the chlorophosphirene complex with AgOSO 2 CF 3 and is in equilibrium with and typically reacts in the same fashion as the phosphirenyl cation. Reaction of 3 with diethylaniline or anisole leads to electrophilic aromatic substitution preferentially at the para position. Reaction with N, N -dimethyl- p -toluidine, in which the para position is blocked, leads to exclusive ortho substitution. The resulting 1,2-substituted arene can adopt a P,N bidentate coordination mode if a CO is removed from tungsten via photolysis. Compound 3 reacts with aromatic heterocycles thiophene, furan, and pyrrole, leading exclusively to substitution in the 2 position, with no evidence for P–S, P–O, or P–N bond formation. Reaction with indole led to substitution at the 3 position, also with no evidence for P–N bond formation. However, upon chromatographic purification, the substituted indole product decomposes into a disubstituted product, with W-coordinated phosphirenyl units at the 3 position and at N. Reaction with phenol and diphenyl amine led exclusively to P–O and P–N bond formation, with no evidence for aromatic substitution. Phosphine products can be removed via oxidation of W with I 2, followed by displacement with bipyridine. A computational study shows that coordination to W(CO) 5 greatly enhances electrophilicity at P in phosphenium ions, leading to the observed rapid electrophilic substitution reactions.
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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) | 0.001 | 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) | 0.002 | 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".