Diverse Coordination Modes and Transformations of Allenes at Adjacent Iridium/Osmium Centers
Bibliographic record
Abstract
The methylene-bridged complex, [IrOs(CO) 3 (μ-CH 2 )(dppm) 2 ][BF 4 ] (dppm = μ-Ph 2 PCH 2 PPh 2 ) ( 2 ), reacts with allene, resulting in C–C bond formation, to yield an equilibrium mix of two isomers of [IrOs(CO) 3 (μ-η 3:κ 1 -C(CH 2 ) 3 )(dppm) 2 ][BF 4 ] ( 3 / 3a ), in which the hapticity of the trimethylenemethane ligand with respect to the two metals, as well as the carbonyl ligand arrangement, is different in each isomer. Reaction of 2, as the triflate salt ( 2-CF 3 SO 3 ), with methylallene also yields two isomers, [IrOs(CO) 3 (μ-η 3:κ 1 -C(CHCH 3 )(CH 2 ) 2 )(dppm) 2 ][CF 3 SO 3 ] ( 4 / 4a ); however, in this case, the binding mode of the substituted trimethylenemethane moiety is the same in each isomer and differs only in the position of the methyl group on the allylic moiety. The addition of 1,1-dimethylallene to 2-CF 3 SO 3 results in loss of 4-methyl-1,3-pentadiene and subsequent reaction of the remaining “[IrOs(CO) 3 (dppm) 2 ] + ” species with excess 1,1-dimethylallene to give [IrOs(CO) 3 (μ-η 3:κ 1 -CH 2 CCMe 2 )(dppm) 2 ][CF 3 SO 3 ] ( 5 ), in which the dimethylallene moiety is κ 1 -bound to Os through the central carbon and η 3 -bound to Ir. Both allene and methylallene react with the tetracarbonyl complex, [IrOs(CO) 4 (dppm) 2 ][BF 4 ] ( 6 ), to generate analogous products, [IrOs(CO) 3 (μ-η 3:κ 1 -CH 2 CCHR)(dppm) 2 ][BF 4 ] (R = H ( 7 ), CH 3 ( 8 ), respectively). Reaction of 6-CF 3 SO 3 with 1,1-dimethylallene yields [IrOs(CO) 4 (μ-C═C(H)C(CH 3 )═CH 2 )(dppm) 2 ][CF 3 SO 3 ] ( 9 ), the result of activation of the geminal C–H bonds of the unsubstituted end of the allene, and additional activation of a methyl C–H bond. The addition of 1,1-difluoroallene to 6-CF 3 SO 3 yields [IrOs(CO) 4 (μ-κ 1:κ 1 -F 2 C═ C ═ C H 2 )(dppm) 2 ] [CF 3 SO 3 ] ( 10 ), in which this cumulene bridges both metal centers through the central carbon and the CH 2 end of the substrate. These reactivities are compared to those of related Ir 2, Rh/Ru, Rh/Os, and Ir/Ru complexes.
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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 | 0.000 | 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 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".