Coordinatively Unsaturated Hydridoruthenium(II) Complexes of N-Heterocyclic Carbenes
Bibliographic record
Abstract
The saturated imidazolin-2-ylidene compounds RNC 3 H 4 NR, with R = mesityl (SIMes), 2,6-diisopropylphenyl, were synthesized by use of diamines that were prepared by the hydrogenation of the corresponding diimines catalyzed by RuHCl( R -binap)( R, R -dach)/KO t Bu in toluene. The ligands IMes (MesNC 3 H 2 NMes) and SIMes react with RuHCl(PPh 3 ) 3 to give RuH(SIMes-H)(PPh 3 ) 2 ( 1 ) and RuH(IMes-H)(PPh 3 ) 2 ( 2 ), respectively, where there is cyclometalation of a C−H bond of an ortho Ar−CH 3 group. The reaction of RuHCl(PPh 3 ) 3 with I t Bu ( t BuNC 3 H 2 N t Bu) produces I t Bu·HCl and a red solution that, upon reaction with H 2, produces the dihydride Ru(H) 2 (I t Bu)(PPh 3 ) 2 as a mixture of the two isomers 3a (trans PPh 3 ligands) and 3b (cis PPh 3 ). These isomers have an agostic C−H bond from a methyl group. There is an interesting windshield wiper exchange of coordinated tert -butyl groups occurring in isomer 3a, as monitored in solution by VT NMR with a free energy of activation of 11.8 kcal/mol. The reaction of 2 with CO at 20 °C produces ( OC -34)-RuH(CO)(PPh 3 ) 2 (IMes-H) ( 4 ), while at 68 °C it forms the Ru(0) complex Ru(CO) 3 (PPh 3 )(IMes) ( 5 ). The reaction of 2 with phenol results in the formation of RuH(η 5 -C 6 H 5 O·HOPh)(IMes)(PPh 3 ) ( 6 ). The structures of complexes 1, 3a, 5, and 6 have been characterized by single-crystal X-ray diffraction.
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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) | 0.002 | 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 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".