Alkyne/Methylene Coupling at Adjacent Iridium/Osmium Centers: Facile Carbon−Carbon and Carbon−Oxygen Bond Formation
Bibliographic record
Abstract
The methylene-bridged complex [IrOs(CO) 4 (μ-CH 2 )(dppm) 2 ][CF 3 SO 3 ] (dppm = μ-Ph 2 PCH 2 PPh 2 ) ( 3 ) can be synthesized by the addition of diazomethane to [IrOs(CO) 5 (dppm) 2 ][CF 3 SO 3 ] ( 1 ) or [IrOs(CO) 4 (dppm) 2 ][CF 3 SO 3 ] ( 2 ). Reaction of 3 with dimethyl acetylenedicarboxylate (DMAD) leads to the insertion of the alkyne into the iridium−carbon bond, yielding both [IrOs(CO) 4 (μ-κ 1:κ 1 -C(CO 2 CH 3 )═C(CO 2 CH 3 )CH 2 )(dppm) 2 ][CF 3 SO 3 ] ( 5 ) and [IrOs(CO) 3 (μ-κ 1:κ 1 -C(CO 2 CH 3 )═C(CO 2 CH 3 )CH 2 )(dppm) 2 ][CF 3 SO 3 ] ( 6 ), each of which can be obtained as the exclusive product under either CO or an Ar purge, respectively. Hexafluorobutyne (HFB) fails to react with 3, but reacts with [IrOs(CO) 3 (μ-CH 2 )(dppm) 2 ][CF 3 SO 3 ] ( 4 ) yielding [IrOs(CO) 3 (μ-κ 1:κ 1 -C(CF 3 )═C(CF 3 )CH 2 )(dppm) 2 ][CF 3 SO 3 ] ( 7 ). Reaction of 7 with diazomethane results in the insertion of a second methylene unit into the iridium−carbon bond, yielding [IrOs(CO) 3 (μ-κ 1:κ 1 -CH 2 (CF 3 )C═C(CF 3 )CH 2 )(dppm) 2 ][CF 3 SO 3 ] ( 9 ), which can be characterized by NMR spectroscopy only at low temperatures owing to deinsertion of the iridium-bound methylene group at ambient temperature. Compound 6 also reacts with diazomethane but in this case results in the formation of a new carbon−oxygen bond between the newly introduced methylene unit and a carbonyl oxygen of the inserted DMAD fragment. This bond formation is accompanied by carbon−hydrogen bond activation of the original osmium-bound methylene group, yielding [IrOs(CO) 3 (μ-H)(μ-κ 1:κ 1:κ 1 -CH 2 OC(OCH 3 )═CC(CO 2 CH 3 )═CH)(dppm) 2 ][CF 3 SO 3 ] ( 8 ). Attempts to insert a methylene unit into the iridium−carbon bond of the alkyne-bridged complexes [IrOs(CO) 3 (μ-κ 1:κ 1 -RC═CR)(dppm) 2 ][CF 3 SO 3 ] (R = CO 2 Me ( 12 ), CF 3 ( 13 )) yields the C 3 -bridged complex [IrOs(CO) 3 (μ-κ 1:κ 1 -CH 2 (CF 3 )C═CCF 3 )(dppm) 2 ][CF 3 SO 3 ] ( 14 ) in the case of 13, but no further methylene incorporation is observed. Compound 12 reacts with diazomethane to give a number of unidentified products under a variety of conditions. The reactivities of the aforementioned complexes are compared to that of related late metal combinations.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 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 | 0.001 |
| 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".