Synthesis, Structures, and Kinetics of Mixed-Donor Amido−Amino−Siloxo Ligands from Symmetrical Diamidosilyl Ether Ligands via a Retro-Brook Rearrangement
Bibliographic record
Abstract
Deprotonation of the new (R = propyl, 3,5-Me(2)Ph) and previously prepared (R = 2,4,6-Me(3)Ph, 2,6-(i)Pr(2)Ph, 3,5-(CF(3))(2)Ph) symmetrical diamidosilyl ether ligand precursors {[RNHSiMe(2)](2)O} with 2 equiv of nBuLi in THF resulted in a new class of mixed-donor amido-amino-siloxo ligands of the form {RNLiSiMe(2)N(R)SiMe(2)OLi} (R= propyl (1c), 3,5-Me(2)Ph (2c), 2,4,6-Me(3)Ph (3c), 2,6-(i)Pr(2)Ph (4c), 3,5-(CF(3))(2)Ph (5c)) in one-step and high yield via a retro-Brook-type rearrangement mechanism. Ligands 1c, 3c, and 4c have been structurally characterized in the presence and absence of THF/ether donor solvents and exhibited a range of aggregated structures with ring-laddering, ring-stacking, and cubane motifs; higher-nuclearity clusters for base-free systems were observed for 1c and 4c. 1H, (7)Li, and selected (13)C{(1)H} NMR spectra in THF-d(8) and toluene-d(8) are described; the (7)Li data are indicative of intramolecular fluxional behavior as a function of temperature but do not shed light on the nuclearity of the salts in solution. Reaction kinetics were investigated by variable-temperature 1H NMR spectroscopy and showed that the rate of rearrangement reactions increases with decreasing steric hindrance and with increasing electron-donating ability of the R substituents, with tau(1/2) values ranging from 5.7 x 10(1) to 1.5 x 10(8) s for 2c and 5c, respectively.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 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".