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 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 | 0.002 | 0.001 |
| Meta-epidemiology (narrow) | 0.002 | 0.002 |
| Meta-epidemiology (broad) | 0.004 | 0.002 |
| Bibliometrics | 0.001 | 0.004 |
| Science and technology studies | 0.002 | 0.002 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| 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; both teacher heads agree on what is shown here.
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".