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 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) | 0.001 | 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; 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".