Hydrogenation of Benzonitrile to Benzylamine Catalyzed by Ruthenium Hydride Complexes with P−NH−NH−P Tetradentate Ligands: Evidence for a Hydridic−Protonic Outer Sphere Mechanism
Bibliographic record
Abstract
The reaction of RuHCl(PPh 3 ) 3 with the tetradentate ligand [PPh 2 (( ortho -C 6 H 4 )CH 2 NHCH 2 - )] 2 {ethP 2 (NH) 2 } in THF produces the new complex trans -RuHCl{ethP 2 (NH) 2 } ( 1 ) as a mixture of two isomers. The complex RuHCl{ethP 2 (NH) 2 } ( 1 ) when activated with KO t Bu/KH is a very active catalyst for the hydrogenation of benzonitrile to benzylamine in toluene, more active than the known catalyst Ru(H 2 ) 2 H 2 (PCy 3 ) 2 ( 2 ). A mixture of 1 and 2 and base also results in efficient conversion of benzonitrile to benzylamine. The complex RuHCl{tmeP 2 (NH) 2 } ( 3 ) where tmeP 2 (NH) 2 is [PPh 2 (( ortho -C 6 H 4 )CH 2 NHCMe 2 - )] 2 is a less active catalyst for this reaction. These catalyst systems are air sensitive and extremely moisture sensitive. Experimental and theoretical (DFT) evidence is presented for a new mechanism for nitrile hydrogenation: the successive hydrogenation of the CN triple bond and then the CN double bond of the intermediate imine by H + /H - transfer from a trans dihydride active catalyst. The amido complex RuH{tmeP 2 N(NH)} ( 4 ) has similar activity to 3 /base for the base-free hydrogenation of benzonitrile and is moderately active for the catalytic hydration of benzonitrile. The new complex RuH(BH 4 ){ethP 2 (NH) 2 } ( 7 ) was prepared by reacting 1 with NaBH 4 but is found to be a poor catalyst for nitrile hydration.
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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) | 0.001 | 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 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".