Preparation, spectroscopic characterization, and deprotonation reactions of Si(NHR)<sub>4</sub> (R = <i>i</i>-Pr, <i>t</i>-Bu, <i>p</i>-tolyl) EPR identification of persistent radicals formed by oxidation of polyimidosilicates
Bibliographic record
Abstract
Treatment of Cl2Si(NH-t-Bu)2 (6a) with t-BuNH2 in boiling toluene yields trisamino(chloro)silane ClSi(NH-t-Bu)3 (7); formation of the tetraaminosilane Si(NH-t-Bu)4 is not observed. The reaction of SiCl4 with 4 equiv. of LiNHR produces the corresponding tetraaminosilanes Si(NHR)4 (2a, R = i-Pr; 2b, R = t-Bu; 2c, R = p-tol) in good yields. When the sterically demanding adamantyl derivative LiHNAd is employed, only disubstitution occurs to form Cl2Si(NHAd)2 (6b). Oxidation of the dimeric imidosilicates {Li3[Si(NR)3(NHR)]·THF}2 (3a, R = i-Pr; 3b, R = t-Bu) with 1 mol of iodine produces the persistent radicals {Li2[Si(NR)3(NHR)]·LiI·3THF}·, which, on the basis of EPR spectra, exist as SiN3Li3I cubes in solution. The spirocyclic tetraimidosilicate monoanion radical {[(THF)2Li(µ-Nnaph)2Si(µ-Nnaph)2Li(THF)2]}· (10) is formed upon oxidation of the tetralithiated species {Li4[Si(Nnaph)4]·4Et2O} (1) and {[Li(12-crown-4)]2[(Et2O)2Li(µ-Nnaph)2Si(µ-Nnaph)2Li(Et2O)2]} (8) with iodine. The spectroscopic characterization of hexa(amino)disiloxane (t-BuNH)3SiOSi(NH-t-Bu)3 (14) formed from the reaction of Cl3SiOSiCl3 with 6 equiv. of LiNH-t-Bu is discussed. Key words: imido ligands, silicate, radicals, EPR spectra, lithium.
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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 | 0.000 | 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) | 0.002 | 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 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".