Synthesis, Characterization, and Properties of the Polyphosphinoboranes [RPH−BH<sub>2</sub>]<i><sub>n</sub></i>(R = Ph,<i>i</i>Bu,<i>p</i>-<i>n</i>BuC<sub>6</sub>H<sub>4</sub>,<i>p</i>-dodecylC<sub>6</sub>H<sub>4</sub>): Inorganic Polymers with a Phosphorus−Boron Backbone
Bibliographic record
Abstract
The polyphosphinoboranes [PhPH−BH 2 ] n ( 1 ), [ i BuPH−BH 2 ] n ( 2 ), [( p - n BuC 6 H 4 )PH−BH 2 ] n ( 3 ), and [( p -dodecylC 6 H 4 )PH−BH 2 ] n ( 4 ) were prepared from the corresponding phosphine−borane adducts RPH 2 ·BH 3 (R = Ph, i Bu, p - n BuC 6 H 4, p -dodecylC 6 H 4 ) via a rhodium-catalyzed dehydrocoupling procedure at elevated temperatures (ca. 90−130 °C). Samples of polymers 1 and 2 and the new materials 3 and 4 were characterized by multinuclear NMR spectroscopy, and the molecular weights were determined by light scattering methods in THF or CH 2 Cl 2 solutions. The absolute weight-average molecular weight of 2 was determined by static light scattering and found to be M w = 13 100, and values of M w of ca. 20 000 were estimated for the sample of polymers 1 and the new material 3 using dynamic light scattering (DLS). The molecular weights of polymers 3 and 4 were also analyzed by gel permeation chromatography using polystyrene standards, and values up to M w = ca. 80 000, M n = ca. 10 000 were determined for 3 and M w = ca. 168 000, M n = ca. 12 000 for 4 . The chemical stability of 1 in THF toward HNEt 2 or n Bu 3 P was demonstrated using NMR spectroscopy and DLS analysis, which indicated that no significant polymer degradation occurred. WAXS analysis of 1 and 3 showed that the polymers are amorphous. The glass transition temperatures ( T g ) of polymers 2, 3, and 4 were analyzed by DSC and were detected at ca. 5, 8, and −1 °C, respectively. TGA analysis on 1 − 3 revealed T 5% values (temperature for which 5% or the weight is lost) of 240 °C for 1 and ca. 150−160 °C for 2 and 3 . After heating to 1000 °C, ceramic yields in the range of 35−80% were obtained. The high ceramic yield for 1 (75−80%) indicates that this material is of interest as a pyrolytic precursor to boron phosphide-based solid-state materials.
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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 | 0.000 |
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".