Ionization of Cp<sub>2</sub>ZrMe<sub>2</sub> and Lewis Bases by Methylaluminoxane: Computational Insights
Bibliographic record
Abstract
Abstract The interactions of the Lewis bases CO, octamethyltrisiloxane (OMTS) and 2,2’‐bipyridine (bipy) with a sheet model for the principal activator (MeAlO) 16 (Me 3 Al) 6 ( 16,6 ) in hydrolytic methylaluminoxane (MAO) were investigated by DFT. These studies reveal that OMTS and bipy form adducts with Me 3 Al prior to methide abstraction by 16,6 to form the ion‐pairs [Me 2 Al(κ 2 ‐L)][ 16,6 ] ( 5 : L=OMTS, 6 : L=bipy, [ 16,6 ] − =[(MeAlO) 16 (Me 3 Al) 6 Me] − ) while CO simply binds to a reactive edge site without ionization. The binding and activation of Cp 2 ZrMe 2 with 16,6 to form both neutral adducts 1 Cp 2 ZrMe 2 ⋅ 16,6 and contact ion‐pairs 4 and 7 , both with formula [Cp 2 ZrMe][μ‐Me(MeAlO) 16 (Me 3 Al) 6 ], featuring terminal and chelated MAO‐anions, respectively was studied by DFT. The displacement of the anion with either excess Cp 2 ZrMe 2 or Me 3 Al was also studied, forming outer‐sphere ion‐pairs [(Cp 2 ZrMe) 2 μ‐Me][ 16,6 ] ( 2 ) and [Cp 2 Zr(μ‐Me) 2 AlMe 2 ][ 16,6 ] ( 3 ). The theoretical NMR spectra of these species were compared to experimental spectra of MAO and Cp 2 ZrMe 2 and found to be in good agreement with the reported data and assignments. These studies confirm that 16,6 is a very suitable model for the activators present in MAO but highlight the difficulty in accurately calculating thermodynamic quantities for molecules in this size regime.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| 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) | 0.008 | 0.001 |
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".