Poly(hydrazinophosphine diazide)s (PHPDs): Hybrid Organic–Inorganic Polymers via Polycondensation between PN Cages and Organic Diazides
Bibliographic record
Abstract
Organic polymers generally feature 1-dimensional chains or 2-dimensional rings in their backbones since synthetic challenges limit the availability of 3-dimensional monomers. Inorganic cages are less strained and more accessible, offering an alternative route to explore this parameter space. However, only two families─carboranes and polyhedral oligomeric silsesquioxanes (POSS)─have been well-studied, revealing materials with valuable mechanical and thermal properties. Further exploration of this frontier requires the development of new inorganic cages that are accessible, stable, and polymerizable. Here we report that an easily assembled, bench-stable PN cage, P(NMeNMe) 3 P, undergoes Staudinger polycondensation with organic diazides to yield robust, solution-processable, and film-forming linear poly(trihydrazino-diphosphine diazide)s─PHPDs─as a new family of hybrid organic–inorganic polymers. Their solubility can be controlled by diazide choice and backbone architecture, which we rationally modify to access alternating or multiblock copolymers. We also show how a tetraphosphorus cage, P 4 (NMe) 6, can be used to cross-link PHPDs. The T g values for PHPDs are comparable to those of rigid π-conjugated polymers (>150 °C), and, despite a high nitrogen content (up to 32%) and three N–N σ-bonds per repeat unit, they show decomposition temperatures >200 °C with char yields up to 60%. These data support hypotheses of high stability arising from the presence of 3-dimensional backbone units. We further show that PHPDs may be leveraged for halogen-free flame retardancy. Collectively, the results debut new low-carbon polymers with an unusual backbone topology, reveal the design rules for controlling their microstructures and properties, and lay the foundation for future applied studies.
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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".