Bridging Methylene to Bridging Acyl Conversion in Heterobinuclear Rh/Ru Complexes: Models for Adjacent-Metal Involvement in Bimetallic Catalysts
Bibliographic record
Abstract
Protonation of the methylene-bridged complex [RhRu(CO) 4 (μ-CH 2 )(dppm) 2 ][CF 3 SO 3 ] ( 1 ) at −80 °C yields an asymmetrically bridged methyl complex in which the methyl ligand is σ-bound to Ru while being involved in an agostic interaction with Rh. Warming to −40 °C results in migration of the methyl group to a terminal site on Rh, and further warming to 0 °C results in migratory insertion to give the acetyl-bridged complex [RhRu(OSO 2 CF 3 )(CO) 2 (μ-C(CH 3 )O)(μ-CO)(dppm) 2 ][CF 3 SO 3 ] ( 4 ), in which the acetyl carbon is bound to Rh and its oxygen is bound to Ru. At ambient temperature one carbonyl is lost from 4 to give [RhRu(OSO 2 CF 3 )(CO) 2 (μ-C(CH 3 )O)(dppm) 2 ][CF 3 SO 3 ] ( 5 ). Carbon-13 NMR spectroscopy and the X-ray structures of both acetyl-bridged products suggest significant carbene character in the acyl carbon. Attempts to obtain methyl and subsequently acetyl species by methylene insertion into metal−hydride bonds of the appropriate precursors [RhRu(X)(CO) 4 (μ-H)(dppm) 2 ][X] (X - = CF 3 SO 3 -, BF 4 - ) failed, with these hydride species being unreactive to CH 2 N 2 . Similarly, reaction of 1 with HCl yielded only the methyl complex [RhRu(CH 3 )(CO) 3 (μ-Cl)(dppm) 2 ][CF 3 SO 3 ], which did not undergo migratory insertion. Protonation of the methylene-bridged PMe 3 adduct [RhRu(PMe 3 )(CO) 3 (μ-CH 2 )(dppm) 2 ][CF 3 SO 3 ] yields [Rh Ru (OSO 2 CF 3 )(CO) 2 (μ- C (CH 3 )O)(dppm) 2 ][CF 3 SO 3 ] in which the binding of the acetyl group is reversed, being C-bound to Ru and O-bound to Rh. This species undergoes facile rearrangement to 5 at ambient temperature.
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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 | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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".