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 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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.006 | 0.005 |
| Meta-epidemiology (broad) | 0.005 | 0.002 |
| Bibliometrics | 0.001 | 0.004 |
| Science and technology studies | 0.002 | 0.004 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.004 | 0.002 |
| Research integrity | 0.003 | 0.004 |
| Insufficient payload (model declined to judge) | 0.000 | 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; both teacher heads agree on what is shown here.
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".