The preparation and characterization of structurally stable 5-coordinate polystannanes
Bibliographic record
Abstract
Tetraorganotin compounds [2-(MeOCH2)C6H4]SnR3 (R = Me, n-Bu, Ph) containing a C,O-chelating ligand were prepared in good yield from the reaction of the R3SnCl and [2-(MeOCH2)C6H4]Li. Tethered organotin compounds Ph3Sn(CH2)3OC6H4R (R = Ph, H, CF3, OCH3) were prepared in good yield from the hydrostannylation reactions of the corresponding vinyl ethers with Ph3SnH. Conversion of two organotin compounds to triorganotin chlorides and diorganotin chlorides, (Ph3-nClnSn(CH2)3OC6H4R; R = H, Ph: n = 1, 2), was successfully carried out and characterisation afforded by NMR spectroscopy. X-ray crystallographic studies revealed a tetrahedral geometry for the tetraorganotin Ph3Sn(CH2)3OC6H4CF3, while five-coordinate trigonal bipyramidal structures with relatively short Sn-O (2.7-2.8 Å) interactions were observed for both mono- (Ph2ClSn(CH2)3OC6H4R; R = H, Ph) and dichloride (PhCl2Sn(CH2)3OC6H4R; R = H, Ph) species. Penta-coordinate diorganotin dichlorides containing a C,N- chelating ligand[2-(Me2NCH2)C6H4]RSnCl2 (R = Me, n-Bu, Ph) or C,O- chelating ligand [2-(MeOCH2)C6H4]RSnCl2 (R = Me, n-Bu, Ph) were prepared by treating RSnCl3 with the lithiated salts [2-(Me2NCH2)C6H4]Li and [2-(MeOCH2)C6H4]Li respectively. Organotin chlorides were successfully reduced with LiAlH4 or NaBH4 to produce novel hydrides. Catalytic dehydrocoupling of diorganotin dihydrides to yield polystannanes was explored using a variety of dehydrocoupling catalysts such as Wilkinson’s catalyst, Cp2ZrMe2 or TMEDA. In almost every instance this resulted in the formation of yellow coloured gummy polymeric materials of moderate molecular weights (Mw = 1 × 104 - 1 × 105 Da) and PDI’s (1.3-2.0). The stability of polystannanes containing tethered O or C,N- or C,O-chelating ligands was investigated in both solid and in solution using NMR and UV-Vis spectroscopies. These studies revealed an enhanced stability to ambient light in the solid state and in solution in the dark when compared to known poly(dialkyl)stannanes.
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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) | 0.001 | 0.001 |
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".