Substitution Effects on the Water Oxidation of Ruthenium Catalysts: A Quantum-Chemical Look
Bibliographic record
Abstract
Quantum chemistry has been used to investigate the oxidation of water by a family of seven catalysts based on [Ru(tpy)(bpy)(OH 2 )] 2+ (tpy = 2,2′:6′,2′′-terpyridine, bpy = 2,2′-bipyridine). The electron-donating −OMe and −NH 2 groups (EDG) and electron-withdrawing −COOH and −NO 2 groups (EWG) are installed in the catalyst by replacing hydrogen atoms on the bpy and tpy ligands. The EDG induces an increase in the electron density at the Ru center, whereas the EWG does the opposite. Reduced electron density at the metal center facilitates Ru(N+1)/Ru(N) reduction and thus a higher reduction potential. Catalytic evolution of one oxygen molecule from two water molecules using all catalysts is an exothermic process if driven by Ce IV . The exothermicity increases from EDG to EWG via parents. Regarding intermediates, the singlet states of 7-coordinated catalysts are slightly more stable than the triplet states of 6-coordinated catalysts for most catalysts. Only for a strong EWG (−NO 2 ) containing catalyst, the triplet 6-coordinated states complex is the most stable. Calculated Ru–O and O–O distances suggest that oxygen will be liberated favorably from the triplet state of 6-coordinated complexes, whose stability increase (with respect to the singlet of 7-coordinated complexes) with increasing electron-withdrawing nature.
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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".