An investigation of the influence of R on the abilities of the polar monomers CH2CH(CH2)8OR (R = Me, PhCH2, Ph3C, Me3Si, Ph3Si) to participate in O- rather than η2-coordination to metallocene alkene polymerization catalysts; an unanticipated role for ether oxygen coordination in promoting polymerization
Bibliographic record
Abstract
Copolymerization of ethylene and propylene with polar monomers of the types CH(2)=CH(CH(2))(n)OH (n = 1-12) in order to introduce polar functionality into the resulting polymers is possible in principle if the hydroxyl groups of the polar monomers are masked such that they cannot coordinate to Lewis acidic catalyst sites and prevent eta(2)-alkene coordination. Although the use of hydrolysable ethers of the types CH(2)=CH(CH(2))(n)OR (R = alkyl, silyl; n = 1-12) is a protecting group strategy, which has been investigated somewhat, in fact this approach has not been investigated systematically and little is known of the effectiveness of various R groups in hindering oxygen coordination to e.g. metallocene polymerization catalyst systems. We report here the results (a) of an NMR study of reactions of an archetypal metallocene polymerization catalyst, Cp(2)ZrMe(mu-Me)B(C(6)F(5))(3), with the polar monomers CH(2)=CH(CH(2))(8)OR (R = Me, PhCH(2), Ph(3)C, Me(3)Si, Ph(3)Si), all protected versions of the readily available, long chain polar monomer 9-decen-1-ol, and (b) of an investigation of the copolymerization reactions of these same polar monomers with ethylene and propylene catalyzed by the well known rac-C(2)H(4)(Ind)(2)ZrCl(2)/MAO catalyst system. While increasing the steric requirements of the groups R does decrease the apparent abilities of the ethers to displace [BMe(C(6)F(5))(3)](-) from the [Cp(2)ZrMe](+) cation, there is no correlation of size of R with the degrees of incorporation of the polar monomers into copolymers of ethylene and propylene. Instead, a heretofore unsuspected role for catalyst activation by the ether linkage is suggested.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.002 |
| 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) | 0.000 | 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 teacher head, 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".