Analysis of H<sub>2</sub> Release from Organic Polycyclics over Pd Catalysts Using DFT
Bibliographic record
Abstract
Density functional theory (DFT) was used to study H 2 release from dodecahydro- N -ethylcarbazole over Pd. Dehydrogenation of the molecule starts from the five-membered ring by weakening the axial C–H bonds adjacent to the N atom. In the adsorption mode identified for dodecahydro- N -ethylcarbazole, the five-membered ring was located on a hollow site and the axial H atoms adjacent to N were positioned atop Pd atoms with an adsorption energy of −95 kJ/mol. The two axial C–H bonds of the five-membered ring showed a large increase in bond distance upon adsorption, from 1.10 to 1.16 Å, that was responsible for the weakening of these bonds. The adsorption mode for dodecahydro- N -ethylcarbazole explained the product distribution obtained from the dehydrogenation reaction with octahydro- N -ethylcarbazole and tetrahydro- N -ethylcarbazole identified as primary and secondary products, respectively. DFT was also used to investigate the structure sensitivity of dodecahydro- N -ethylcarbazole dehydrogenation observed on Pd catalysts. The effect of the ethyl group and N atom on the rate of dodecahydro- N -ethylcarbazole dehydrogenation was also investigated by comparing the adsorption energies of dodecahydro- N -ethylcarbazole with two other H 2 storage candidates, dodecahydrocarbazole and dodecahydrofluorene. The latter compounds had much slower H 2 recovery rates, a consequence of the strong adsorption of these compounds relative to dodecahydro- N -ethylcarbazole.
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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".