Catalytic Consequences of Protons in Methanol Oxidative Dehydrogenation on Molybdenum-Based Polyoxometalate Clusters
Bibliographic record
Abstract
This study unravels the catalytic effects of adjacent protons in redox catalysis of bifunctional Keggin-type phosphomolybdic acid clusters (H 3 PMo 12 O 40 ). Isolated redox sites (O*) and Brønsted acid-redox site pairs (OH/O*) catalyze methanol oxidative dehydrogenation (ODH), a redox reaction, via the identical elementary steps and the formation of the kinetically relevant [HOCH 2 ···H···O*] ‡ and [OH···HOCH 2 ···H···O*] ‡ transition states, but with different kinetic requirements, established from selective site inactivation, product tracking, dynamic pyridine/2,6-di- tert -butylpyridine titrations, and kinetic assessments. The presence of adjacent protons interacts with and stabilizes the methanol precursor in the OH···HOCH 2 –H···O* adsorbed state through additional H-bonding interactions by 57 kJ mol –1 in adsorption enthalpy and by 144 J mol –1 K –1 in adsorption entropy. These additional interactions, stabilizing the [OH···HOCH 2 ···H···O*] ‡ transition state, lead to a decrease in apparent methanol activation enthalpy of 50 kJ mol –1 and in activation entropy of 97 J mol –1 K –1, resulting in an overall increase in methanol ODH turnovers. The kinetic consequences of protons established here enable the rationalization of the redox reactivity on bifunctional POM clusters and display a nontraditional confinement effect to stabilize transition state energies.
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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".