Cooperative Au <sub>vertex</sub> –Au <sub>shoulder</sub> Pair Sites of Biicosahedral Au <sub>25</sub> Cluster for Highly Oxidative Carbonylation of Diamine to Cyclic Urea
Bibliographic record
Abstract
Abstract The realization of target reactants completely transformed on the designed active sites toward desired products remains a challenge. Here, we report that the [Au 25 (PPh 3 ) 10 (SCH 2 CH 2 Ph) 5 Cl 2 ] 2+ cluster in the library of metal clusters is unique for the oxidative carbonylation of diamine to cyclic urea. Our studies reveal that the ligand on–off dynamics in the presence of solvent coupled with diamine can invoke the active function of the vertex and shoulder Au of the [Au 25 (PPh 3 ) 10 (SCH 2 CH 2 Ph) 5 Cl 2 ] 2+ , i.e., that is respectively capped by Cl and PPh 3 . Notably, the transient exposed Au vertex –Au shoulder neighboring sites exhibit a selective recognition to reaction molecules, leading to the interdependent and stepwise reactivity for the oxidative carbonylation of diamine with CO and O 2 . The diamine is preferentially adsorbed on the Au shoulder site, with the CO inserting sequentially into the diamine to produce the key intermediate containing the secondary amide group, and meanwhile the Au vertex site engages in converting O 2 to singlet oxygen and finally enables the H‐atom abstraction from the amine group of the above intermediate, thereby achieving an exclusive selectivity for cyclic urea. This work provides an alternative route for the efficient carbonylation upgrading of diamine, typically distinguished from homogeneous organometallic complexes and heterogeneous supported metal catalysts.
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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".