Dihydridoamine and Hydridoamido Complexes of Ruthenium(II) with a Tetradentate P−N−N−P Donor Ligand
Bibliographic record
Abstract
The new diphosphinediimine ligand PPh 2 C 6 H 4 CH NCMe 2 CMe 2 N CHC 6 H 4 PPh 2 {tmeP 2 N 2 } is prepared by reacting NH 2 CMe 2 CMe 2 NH 2 with 2 equiv of PPh 2 (C 6 H 4 -2-CHO). The diamine derivative PPh 2 C 6 H 4 CH 2 NHCMe 2 CMe 2 NHCH 2 C 6 H 4 PPh 2 {tmeP 2 (NH) 2 } is prepared by reducing tmeP 2 N 2 with LiAlH 4 . The reaction of RuHCl(PPh 3 ) 3 with tmeP 2 N 2 in THF produces the complex trans -RuHCl{tmeP 2 N 2 }, while a similar reaction of RuHCl(PPh 3 ) 3 with tmeP 2 (NH) 2 gives the complex trans -RuHCl{tmeP 2 (NH) 2 }, as a mixture of two isomers. The isomer with two N−H bonds syn to the Ru−H bond is converted on heating to an isomer thought to have one N−H syn to the Ru−H. The reaction of the two isomers with KO t Bu under Ar in toluene produces the novel hydridoamido complex RuH{tmeP 2 NNH}, where the ligand is deprotonated at one nitrogen. Reaction of this amido complex with H 2 gives exclusively the dihydridoamine complex trans -Ru(H) 2 {tmeP 2 (NH) 2 }. The complexes have been characterized by X-ray crystallography, NMR, IR, elemental analysis, and a deuterium exchange study. Complex RuH{tmeP 2 NNH}, or a combination of RuHCl{tmeP 2 (NH) 2 } and KO t Bu, slowly catalyzes the hydrogenation of acetophenone (6 atm H 2, 20 °C, benzene or 2-propanol). The catalytic cycle is thought to be similar to that for the ketone hydrogenation precatalyst trans -RuHCl{(S,S)-cyP 2 (NH) 2 )}. However in the present work both of the proposed catalysts trans -RuH 2 {tmeP 2 (NH) 2 } and RuH{tmeP 2 NNH} have been completely characterized. The tmeP 2 (NH) 2 system, with hindering methyl groups, is less active than the cyP 2 (NH) 2 system with a trans -1,2-substituted cyclohexyl backbone. The variable configuration of the amine nitrogens that is observed for the tmeP 2 (NH) 2 complexes might also occur in the cyP 2 (NH) 2 systems and could explain the inconsistent selectivity of such catalysts. The diimine complex RuHCl{tmeP 2 N 2 } reacts with KO t Bu under H 2 to produce the dihydridodiamine complex trans -Ru(H) 2 {tmeP 2 (NH) 2 }, the catalyst for the hydrogenation of acetophenone.
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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 | 0.001 |
| 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) | 0.000 | 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".