Exploring the Influence of Ancillary Ligand Charge and Geometry on the Properties of New Coordinatively Unsaturated Cp*(κ<sup>2</sup>-<i>P</i>,<i>N</i>)Ru<sup>+</sup>Complexes: Linkage Isomerism, Double C−H Bond Activation, and Reversible α-Hydride Elimination
Bibliographic record
Abstract
The synthesis, characterization, and reactivity properties of new Cp*Ru complexes supported by κ 2 - P, N -1-P i Pr 2 -2-NMe 2 -indene ( 1a ), κ 2 - P, N -2-NMe 2 -3-P i Pr 2 -indene ( 1b ), and κ 2 - P, N -2-NMe 2 -3-P i Pr 2 -indenide ( 1 ) are described (Cp* = η 5 -C 5 Me 5 ). Addition of 1a to (Cp*RuCl) 4 afforded Cp*Ru(Cl)(κ 2 - P, N - 1a ) ( 2a, 92%), which in turn was transformed into Cp*Ru(Cl)(κ 2 - P, N - 1b ) ( 2b, 85%). Treatment of either 2a or 2b with AgBF 4 in acetonitrile provided the corresponding 18-electron, base-stabilized cation [Cp*Ru(CH 3 CN)(κ 2 - P, N - 1a, b )] + BF 4 - ( 3a, 89%; 3b, 91%). In the pursuit of the analogous acetonitrile-free, 16-electron species ( 4a or 4b ), complexes 2a or 2b were treated with Li(Et 2 O) 2.5 B(C 6 F 5 ) 4 . In the case of 2a, the linkage isomer [Cp*Ru(η 6 - 1a )] + B(C 6 F 5 ) 4 - ( endo - 4c, 74%) was obtained; exposure of this complex to triethylamine afforded [Cp*Ru(η 6 - 1b )] + B(C 6 F 5 ) 4 - ( 4d, 85%). In contrast, chloride abstraction from 2b generated the C−H bond activation product 4e (83%); variable-temperature NMR data revealed that the apparent cyclometalation of 4b to give 4e is reversible. While the base-stabilized zwitterion 5a ·CH 3 CN was successfully prepared (83%), attempts to generate the coordinatively unsaturated zwitterion Cp*Ru(κ 2 - P, N - 1 ) ( 5a ) instead resulted in the formation of the isomeric hydridocarbenes 5b (80%) and 5c (84%). The apparent rearrangement of 5a to a hydridocarbene is noteworthy, as it represents a remarkably facile, ligand-assisted double geminal C−H bond activation process. Moreover, data obtained from 1D- and 2D-EXSY NMR experiments involving 5c provided compelling evidence for what appears to be the first documented interconversion of Ru(H) CH and Ru−CH 2 groups by way of reversible α-hydride elimination. In keeping with this dynamic process, treatment of 5c with PHPh 2 afforded the alkylruthenium adduct 6 (70%). Single-crystal X-ray diffraction data are provided for 2a, 2b, 3a, 3b ·1.5C 5 H 12, 4d, 4e, ( 5a ·CH 3 CN)·0.5CH 3 CN, 5c, and 6 ·0.5C 5 H 12 .
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 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 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".