Mass Spectrometric Characterization of Methylaluminoxane
Bibliographic record
Abstract
Electrospray ionization mass spectrometric studies of poly(methylaluminoxane) (MAO) in the presence of Cp 2 ZrMe 2, octamethyltrisiloxane (OMTS), or [Bu 4 N]Cl in fluorobenzene solution are reported. The results concur with the hypothesis that MAO is partially ionized in sufficiently polar media, where the contact ion pairs are of the general formula [Me 2 Al][(MeAlO) x (AlMe 3 ) y Me]. A limited number of compositions of this type are detected; the most abundant has x = 23 and y = 7, where the cation [Me 2 Al(OMTS)] + (with m / z 293) and the anion (with m / z 1853) were detected in the presence of OMTS, which stabilizes the Me 2 Al cation. The results demonstrate that MAO ionizes Cp 2 ZrMe 2 by acting as a source of this electrophilic cation, giving rise to an ion pair featuring a large and weakly coordinating aluminoxanate counterion.
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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 | 0.001 | 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) | 0.004 | 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".