Diamido-Ether Uranium(IV) Alkyl Complexes as Single-Component Ethylene Polymerization Catalysts
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Bibliographic record
Abstract
The synthesis and characterization of two new uranium(IV) dialkyl complexes supported by two different diamido ether ligands are reported. The reaction of [{({2,6- i Pr 2 C 6 H 3 }N{CH 2 CH 2 }) 2 O}UCl 2 ] ([{ dipp NCOCN}UCl 2 ]) with 2 equiv of KCH 2 Ph generates the organoactinide [{ dipp NCOCN}U(CH 2 Ph) 2 ] ( 3 ), which shows an η 1 -, η 2 -benzyl arrangement of the alkyl ligands in the solid state. Reaction of [({ t BuN(SiMe 2 )} 2 O)UCl 2 ] ([{ t Bu NON}UCl 2 ]) with 2 equiv of LiCH(SiMe 3 ) 2 yields the alkyl-bridged uranium dimer [{ t Bu NON}U{CH(SiMe 3 )(SiMe 2 CH 2 )}] 2 ( 4 ), which forms via γ C−H activation of the CH(SiMe 3 ) 2 substituent. Reaction of 3 and 4 as well as previously reported [{ t Bu NON}U(CH 2 SiMe 3 ) 2 ] ( 1 ) and [{ dipp NCOCN}U(CH 2 SiMe 3 ) 2 ] ( 2 ) with 1 atm of ethylene under ambient conditions produced high molecular weight polymers, demonstrating that diamido ether actinide complexes can act as ethylene polymerization catalysts; activities up to 560 g/mol·h·atm using 1 were observed. Reaction of 1 and 2 with 1 atm of ethylene and 1 equiv of B(C 6 F 5 ) 3 demonstrated a 4-fold decrease in activity of the catalyst. Reaction of 1 or 2 with an excess of MMAO or Et 2 AlCl did not yield any polymer formation upon the addition of ethylene. After reaction of 1 with Et 2 AlCl, removal of volatiles in vacuo yielded a dark red liquid that, upon standing, formed green crystals of [{ t Bu NON}U{(μ-Cl) 2 AlEt 2 } 2 ] ( 5 ), indicating a route for catalyst deactivation by aluminum-based cocatalysts.
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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 | 0.000 | 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) | 0.008 | 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 it