Bis(diethylphosphino)methane As a Bridging Ligand in Complexes of Ir<sub>2</sub>, Rh<sub>2</sub>, and IrRh: Geminal C–H Activation of α-Olefins
Bibliographic record
Abstract
Bis(diethylphosphino)methane (depm, Et 2 PCH 2 PEt 2 ) is used as a new bridging ligand for the syntheses of a series of diiridium, dirhodium, and iridium/rhodium complexes, starting from trans -[MM′Cl 2 (CO) 2 (depm) 2 ] (M = M′ = Ir ( 1 ); M = M′ = Rh ( 11 ); M = Ir, M′ = Rh ( 19 )). The reduction of all three chloro compounds in aqueous KOH under an atmosphere of CO produces the neutral tricarbonyl complexes [MM′(CO) 3 (depm) 2 ] (M = M′ = Ir ( 2 ); M = M′ = Rh ( 12 ); M = Ir, M′ = Rh ( 20 )). Protonation of these tricarbonyl complexes by triflic acid (HOTf) or Brookhart’s acid (HBAr F 4 ) yields the hydride-bridged tricarbonyl complexes [MM′(CO) 3 (μ-H)(depm) 2 ][X] (M = M′ = Ir ( 9 ); M = M′ = Rh ( 16 ); M = Ir, M′ = Rh ( 25 ); X = SO 3 CF 3 or B(3,5-(CF 3 ) 2 C 6 H 3 ) 4 ). Reaction of 2 with methyl triflate yields the methylene/hydride product [Ir 2 (H)(CO) 3 (μ-CH 2 )(depm) 2 ][OTf] ( 4 ), while the same reaction with the dirhodium analogue ( 12 ) produces the methyl complex [Rh 2 (CH 3 )(CO) 3 (depm) 2 ][OTf] ( 14 ) at below −20 °C, which upon warming to above −20 °C results in migratory insertion to yield an acetyl-bridged species, [Rh 2 (CO) 2 (μ-C(CH 3 )O)(depm) 2 ][OTf] ( 14a ). The analogous Rh/Ir species( 20 ) reacts with methyl triflate to give the methyl-tricarbonyl product [IrRh(CH 3 )(CO) 3 (depm) 2 ][OTf] ( 22 ). Removal of a carbonyl from 4 and 22 yields [MIr(CH 3 )(CO) 2 (depm) 2 ][OTf] (M = Ir ( 5 ); M = Rh ( 23 )), which are highly susceptible to hydrolysis; however the dirhodium species 14 and 14a are not susceptible to CO loss under the conditions investigated. The reaction of [Ir 2 (CO) 3 (μ-H)(depm) 2 ][BAr F 4 ] ( 9 ) with a number of α-olefins results in double C–H bond activation of the geminal hydrogens to give the vinylidene-bridged trihydride products of the form [Ir 2 (H) 2 (CO) 2 (μ-H)(μ-C═CRR′)(depm) 2 ][BAr F 4 ].
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| 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) | 0.000 | 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 teacher head, 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".