Reactions of the Binuclear Complexes [MIr(CO)<sub>3</sub>(Ph<sub>2</sub>PCH<sub>2</sub>PPh<sub>2</sub>)<sub>2</sub>] (M = Rh, Ir) with Alkyl Halides: Dramatic Reactivity Differences as a Function of Metal Combination and Alkyl Halide
Bibliographic record
Abstract
Reactions of [Ir 2 (CO) 3 (dppm) 2 ] ( 1; dppm = Ph 2 PCH 2 PPh 2 ) with CH 3 I and CH 3 OCH 2 I give the oxidative-addition products [Ir 2 (R)(I)(CO)(μ-CO)(dppm) 2 ] (R = CH 3 ( 3 ), CH 2 OCH 3 ( 4 )). The X-ray structure determination of 4 ·CH 2 Cl 2 shows that the alkyl group is the sole terminal ligand on one metal while the iodo and a carbonyl are terminally bound to the adjacent metal. The mixed-metal analogue [RhIr(CO) 3 (dppm) 2 ] ( 2 ) does not react with CH 3 I but reacts with CH 3 OCH 2 I to give [RhIr(CH 2 OCH 3 )(I)(CO)(μ-CO)(dppm) 2 ] ( 5 ). Reaction of 3 or 5 with methyl triflate results in iodide abstraction to yield the known compound [Ir 2 (CH 3 )(CO)(μ-CO)(dppm) 2 ][CF 3 SO 3 ] and [RhIr(CH 2 OCH 3 )(CO)(μ-CO)(dppm) 2 ][CF 3 SO 3 ] ( 8 ), respectively. In the mixed-metal compound iodide removal results in migration of the methoxymethyl group from Rh to Ir. Iodide abstraction from 4 results in a double C−H bond activation to yield the methoxycarbyne-bridged [Ir 2 (H) 2 (CO) 2 (μ-COCH 3 )(dppm) 2 ][CF 3 SO 3 ] ( 6 ). In the reactions of 4 and 5 with methyl triflate some methoxide abstraction also occurs, yielding the methylene-bridged products [MIr(CO) 2 (μ-CH 2 )(μ-I)(dppm) 2 ][CF 3 SO 3 ] (M = Ir ( 7 ), Rh ( 9 )) as minor products in between 15 and 30% yield. The reactions of [MIr(CO) 3 (dppm) 2 ] (M = Ir ( 1 ), Rh ( 2 )) with CH 2 I 2 and ICH 2 CN yield [MIr(CO) 2 (μ-I)(μ-CO)(Ph 2 PCHPPh 2 )(dppm)] (M = Ir ( 10 ), Rh ( 11 )) together with CH 3 I and CH 3 CN, respectively, by hydrogen abstraction from one of the dppm ligands and iodine atom coordination at the metals. Reactions of 1 with allyl bromide and benzyl bromide yield the bromo analogue [Ir 2 (CO) 2 (μ-Br)(μ-CO)(Ph 2 PCHPPh 2 )(dppm) 2 ] ( 12 ). The X-ray structure of 10 ·THF has been determined and shows a planar Ir−P−C(H)−P−Ir moiety, short P−C bonds (1.72(2) Å), and a 122(1)° angle at carbon of the Ph 2 PC(H)PPh 2 ligand, as expected for sp 2 hybridization and partial multiple-bond character in the P−C bonds.
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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) | 0.002 | 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".