NHC Complexes of Osmium Clusters: A Structural and Reactivity Study
Bibliographic record
Abstract
A carbene transfer agent, 1,3-bis-(2,4,6-trimethylphenyl)imidazol-2-ylidene-silver(I)chloride ([IMes]AgCl), was treated with various osmium clusters. Reaction of ([IMes]AgCl) with [Os 3 (μ-H) 2 (CO) 10 ] gave [Os 3 (μ-H)(μ-Cl)(CO) 9 (IMes)] ( 1 ), an osmium N -heterocyclic carbene complex. The reaction of ([IMes]AgCl) with the cluster [Os 3 (CO) 10 (CH 3 CN) 2 ] yielded two products, [Os 3 (μ-Cl)(CO) 10 (μ-Ag(IMes)] ( 2 ) and [(IMes-H)][Os 3 (μ-Cl)(CO) 10 ](μ 4 -Ag)[Os 3 (μ-Cl)(CO) 10 ] ( 3 ). Compound ( 2 ) is a heterobimetallic carbene complex resulting from the complete incorporation of ([IMes]AgCl). Transmetalation using [(IMes)AgCl] and the cluster [Os 4 (μ-H) 4 (CO) 12 ] in the presence of trimethylamine- N -oxide resulted in the formation of [Os 4 (μ-H) 4 (CO) 11 ( n ·IMes)] ( 4 ), where ( n denotes normal carbene bonding, i.e., through C 2 ). [Os 4 (μ-H) 4 (CO) 10 (IMes) 2 ] ( 5 ) was formed using the activated cluster [Os 4 (μ-H) 4 (CO) 10 (CH 3 CN) 2 ] and [(IMes)AgCl]. Compound ( 5 ) was found to be sensitive to silica gel column chromatography in the presence of dichloromethane decomposing to [Os 4 (μ-H) 3 (μ-Cl)(CO) 11 (IMes)] ( 6 ), which possessed a butterfly metal skeleton. The ruthenium analogue of ( 4 ), [Ru 4 (μ-H) 4 (CO) 11 (IMes)] ( 7 ), was prepared and identified spectroscopically but was found to be thermally unstable. Thermolysis of ( 4 ) in benzene yielded four products. The abnormal carbene complex [Os 4 (μ-H) 4 (CO) 11 ( a ·IMes)] ( 10 ) ( a denotes abnormal carbene bonding through C 3 or C 4 ), an isomer of ( 4 ), and {Os 4 (μ-H)(CO) 10 [(η-C)N(Mes)C 2 H 2 NC 6 H 2 (CH 3 ) 2 (η 2 -C)(η-C)C 4 H 4 (η 2 -C)]} ( 11 ), an unusual complex resulting from the activation of benzene and activation of three C−H bonds on IMes, were isolated in modest yields. Two higher-nuclearity clusters, {Os 5 (μ 5 -C)(CO) 14 [η-C-η-NC 2 H 2 (Mes)]} ( 8 ) and [Os 6 (μ-H) 4 (μ 5 -C)(CO) 15 (IMes)] ( 9 ), both of which contain carbide ligands, were also isolated. {Os 4 (μ-H)(CO) 10 [(η-C)N(Mes)C 2 H 2 NC 6 H 2 (CH 3 ) 2 (η 2 -C)(η-C)CHC(CH 3 )C 2 H 2 (η 2 -C)]} ( 12 ), an analogue of ( 10 ), resulted from the thermolysis of ( 4 ) in toluene indicates that the reaction is potentially general and exhibits some regioselectivity. Crystal structure determinations were completed on all 11 osmium cluster 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) | 0.002 | 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".