Pressure effects and solvent dynamics in the electrochemical kinetics of the tris(hexafluoroacetylacetonato)ruthenium(III)/(II) couple in nonaqueous solvents
Bibliographic record
Abstract
Rate constants and reactant diffusion coefficients for the Ru(hfac)30/ electrode reaction have been measured at 25°C as functions of pressure (0-200 MPa) in acetone, acetonitrile, methanol, and propylene carbonate. In sharp contrast to the negative volumes of activation ΔVex found for the corresponding bimolecular self-exchange reaction in organic solvents, the volumes of activation ΔVel for the electrode reaction are markedly positive, ranging from 8 to 12 cm3 mol1. The volumes of activation ΔVdiff for reactant diffusion (which can be equated to the volume of activation ΔVvisc for viscous flow) range from 12 to 19 cm3 mol1. For the Debye solvents acetonitrile and acetone at least, ΔVel is given within the experimental uncertainty by ΔVdiff + (ΔVex/2). In this relation, the numerical value of ΔVdiff represents indirectly the dominant contribution of solvent dynamics (solvent friction) to ΔVel, and ΔVex/2 represents the pressure dependence of the free-energy barrier height for the electrode reaction. It is proposed that solvent friction is important in nonaqueous electrode processes but not in the corresponding bimolecular self-exchange reactions because the free-energy activation barrier is twice as high in the latter.Key words: electrode reaction kinetics, solvent dynamics, electron transfer mechanisms, pressure effects, volume of activation.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 |
| 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".