Hypercoordinating Stannanes with C,N-Donor Ligands: A Structural, Computational, and Polymerization Study
Bibliographic record
Abstract
Select triphenyl stannanes bearing either a formally sp2 or sp3 hybridized amine, viz 2-(pyC2H4)SnPh3 (2: py = pyridinyl), 4-(pyC2H4)SnPh3 (3), 2-(pzC2H4)SnPh3 (4: pz = pyrazyl), and Me2N(CH2)3SnPh3 (6), were prepared and characterized by NMR spectroscopy (119Sn, 13C, 1H), and additionally, in the case of 2, by single crystal X-ray diffraction. Bromination of 2 to yield 2-(pyC2H4)SnPhBr2 (8) was achieved in good yield. X-ray crystallographic analysis of 8 revealed two unique molecules with 5-coordinate Sn centers featuring Sn-N distances of 2.382 (5) and 2.363 (5) Å, respectively. The calculated structures of the non- and hypercoordinating C,N-stannanes (1–9) were in good agreement with available crystallographic data. The relative stabilities of hyper- and non-hypercoordinating conformers obtained from conformational sampling were determined by comparison with reference conformers and by natural bond orbital (NBO) energetic analyses. Reduction of 8 to the dihydride species, 2-(pyC2H4)SnPhH2 (9), and subsequent conversion to the polystannane, -[2-(pyC2H4)SnPh]n- (15), by transition metal-catalyzed dehydropolymerization was also achieved. Evidence for the decomposition of 15 into a redistributed distannoxane, {2-(pyC2H4)SnPh2}2O (16), was also observed.
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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 | 0.001 |
| 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".