Kinetics and Magnetism of Phosphane Diadducts of Diruthenium(II,III) Tetraacetate
Bibliographic record
Abstract
Abstract The kinetic parameters for the axial‐ligand‐substitution reactions of [Ru2(μ‐O2CCH3)4(MeCN)2]+ in acetonitrile (MeCN) with PCy3 and PCy2Ph (Cy = cyclohexyl and Ph = phenyl) were investigated under pseudo first‐order conditions of excess phosphane. The rate‐determining formation of [Ru2(μ‐O2CCH3)4(MeCN)(PCy2R]+ appears independent of the nature of the incoming phosphane with an average k1 (25.0 °C) = (1.25 ± 0.06) × 103 M–1 s–1. A dissociatively activated mechanism is proposed for substitution of the axially coordinated acetonitrile, and the rate parameters are compared to earlier measurements carried out on [Rh2(μ‐O2CCH3)4(MeCN)2]. Variable‐temperature magnetic susceptibility measurements were carried out on the two phosphane diadducts, [Ru2(μ‐O2CCH3)4(PCy3)2]PF6, (1) and [Ru2(μ‐O2CCH3)4(PCy2Ph)2]PF6 (2), and showed behaviour unique to a Boltzmann distribution of states over the temperature range 2–300 K. To support the magnetic measurements, the single‐crystal X‐ray structure of 1 was redetermined at various temperatures down to –150 °C and showed a distinct decrease in the Ru–Ru bond length with decreasing temperature, consistent with a σ2π4δ2π*3 configuration at low temperature (ground state) and a σ2π4δ2π*2δ*1 configuration at room temp. In addition, the structure redeterminations of 1 were better resolved than the earlier reported structure and also corrected a minor error in that the molecule of solvation was found to be 1,2‐dichloroethane instead of dichloromethane. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
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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 | 0.001 |
| 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".