DFT mechanistic studies on the epoxidation of cyclohexene by non-heme tetraaza manganese complexes
Bibliographic record
Abstract
Herein, we report density functional calculations on the epoxidation of cyclohexene with H2O2 activated by (Me2EBC)MnCl2 (Me2EBC stands for 4,11-dimethyl-1,4,8,11-tetraazabicyclo[6.6.2]hexadecane). The computed energy landscapes for different interaction modes of cyclohexene with the MnIV-hydroperoxo complex and the MnV-oxo species support recent experimental findings by Busch and co-workers [J. Am. Chem. Soc. 127, 17170 (2005)], according to which the MnIV-hydroperoxo species is the active complex for olefin epoxidation. Thus, the dominant olefin epoxidation pathway is via direct transfer of the distal protonated oxygen of the hydroperoxo adduct without changes in the oxydation state of its tetravalent metal centre, i.e., the mechanism commonly observed in the uncatalyzed epoxidation by peracids. The homolytic decomposition of the O–OH bond in the active manganese complex leading to the MnV-oxo species is found to be the only epoxidation pathway that could possibly compete with the Oβ transfer from the hydroperoxo adduct. However, the generated MnV-oxo is shown to be a rather poor oxidant resulting in low yields of the target epoxy cyclohexane.Key words: epoxidation, density functional theory, permanganic acid, peracid.
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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.005 | 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".