Half-Sandwich Silane σ-Complexes of Ruthenium Supported by NHC Carbene
Bibliographic record
Abstract
Reactions of carbene complex [Cp(IPr)Ru(pyr) 2 ][BF 4 ] ( 6, IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) with excess acetonitrile and LiCl in THF afford complexes [Cp(IPr)Ru(NCCH 3 ) 2 ][PF 6 ] ( 7 ) and Cp(IPr)RuCl ( 8 ), respectively. Complex 8 was characterized by NMR and X-ray diffraction analysis. Addition of hydrosilanes to 8 results in silane σ-complexes Cp(IPr)Ru(η 2 -HSiR 3 )Cl ( 4 ), which were characterized by NMR and X-ray studies of Cp(IPr)Ru(η 2 -HSiMeCl 2 )Cl ( 4b ) and Cp(IPr)Ru(η 2 -H 3 SiPh)Cl ( 4d ). The hydrogen–silicon coupling constants of complexes 4 show an unusual trend in that the J (H–Si) values increase from the less-chlorinated complex Cp(IPr)Ru(η 2 -HSiMe 2 Cl)Cl ( 4c ) to the trichloro derivative Cp(IPr)Ru(η 2 -HSiCl 3 )Cl ( 4a ). Reaction of Cp(IPr)RuCl ( 8 ) with two equivalents of HSiCl 3 gave the ruthenate complex [IPrH] + [CpRuCl(H) (SiCl 3 ) 2 ] −, characterized by NMR and X-ray study. Addition of hydrosilanes to the cationic complex [Cp(IPr)Ru(NCCH 3 ) 2 ][BAr F 4 ] ( 9 ) furnished very unstable cationic silane σ-complexes [Cp(IPr)Ru(η 2 -HSiR 3 )(NCCH 3 )] + ( 5 ), characterized by low-temperature NMR. Reaction of complex 9 with two equivalents of HSiCl 3 gives the neutral bis(silyl) complex CpRu(NCCH 3 )(H)(SiCl 3 ) 2 and [IPrH][BAr F 4 ]. Catalytic studies showed that 9 is a poorer catalyst for hydrosilylation of benzaldehyde, benzonitrile, and pyridine than its phosphine analogue [Cp( i Pr 3 P)Ru(NCCH 3 ) 2 ][BAr F 4 ]. The reason for this reduced activity was assigned to the easy dissociation of carbene from the former catalyst.
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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 | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".