Formation of CoIV=O intermediate at the Boundary of the “Oxo-wall” Induces Water Oxidation
Bibliographic record
Abstract
Abstract Development of economically viable artificial photosynthesis requires use of 3d metal-based catalysts. Water oxidation by [Co4O4]n+ cubane mimics water splitting by CaMn4O5 cluster in Nature but the exact mechanism of O-O bond formation is presently unknown. We demonstrate first in situ detection CoIV=O (~ 1.67 Å) moiety formed upon activation of [Co4O4Py4Ac4]0 (Py = pyridine and Ac = CH3COO−) towards O-O bond formation. Combined spectroscopic and DFT analyses show that the intermediate active in O-O bond formation has two CoIV centers and at least one CoIV=O unit of strong radicaloid character that participates in O-O bond formation via water nucleophilic attack. The multimetallic structure of the cubane provides unique stabilization for CoIV=O + H2O = Co-OOH + H+ transition with the carboxyl accepting the proton and the bridging oxygen stabilizing the peroxide via hydrogen bonding. Results are important for development of oxygen evolution catalysts based on Earth-abundant 3d elements.
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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) | 0.002 | 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".