Alkali aminoether-phenolate complexes: synthesis, structural characterization and evidence for an activated monomer ROP mechanism
Bibliographic record
Abstract
Several monometallic {LO(i)}M complexes of lithium (M = Li; i = 1 (1), 2 (2), 3 (3)) or potassium (M = K, i = 3 (4)) and the heteroleptic bimetallic lithium complex {LO(3)}Li·LiN(SiMe2H)2 (5), all supported by monoanionic aminoether-phenolate {LO(i)}(-) (i = 1-3) ligands, have been synthesized and structurally characterized. A large range of coordination motifs is represented in the solid state, depending on the chelating ability of the ligand, the size of the metal and the number of metallic centres found in the complex. Pulse-gradient spin-echo NMR showed that 1-4 are monomeric in solution, irrespective of their (mono- or di)nuclearity in the solid-state. VT (7)Li and DOSY NMR measurements conducted for 5 indicated that the two Li atoms in the complex do not exchange positions even at 80 °C. Upon addition of 1-10 equiv. of BnOH, the electron-rich and sterically congested {LO(3)}Li complex (3) promotes the controlled living and immortal ring-opening polymerisation of L-lactide. The combination of polymer end-group analyses and stoichiometric model reactions unambiguously provided evidence that ROP reactions catalyzed by these two-component {LO(i)}Li/BnOH catalyst systems operate according to an activated monomer mechanism, and not via the coordination-insertion scenario frequently assumed for similar alkali phenolate-alcohol systems.
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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 | 0.000 | 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 | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.002 |
| 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 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".