Synthesis of Linear and Cyclic Carbophosphazenes via an Oxidative Chlorination Strategy
Bibliographic record
Abstract
The use of a mild, oxidative chlorination route for the synthesis of linear and cyclic carbophosphazenes is described. For example, chlorination of the linear PNCN chain Ph(2)P-N=C(Ph)-N(SiMe(3))(2) (1) with C(2)Cl(6) led to the clean formation of the previously known 8- and 6-membered rings [Ph(2)PNC(Ph)N](2) (2) and [Ph(2)PNC(Ph)NP(Ph)(2)N] (3), respectively. In a similar fashion, the N-alkyl-substituted PNCN derivatives, Ph(2)P-N=C(Ph)-N((t)Bu)SiMe(3) (4) and Ph(2)P-N=C(Ph)-N(i)Pr(2) (7) were readily converted by C(2)Cl(6) into the halogenated derivatives ClPh(2)P=N-C(Ph)=N(t)Bu (5) and [ClPh(2)P=N=C(Ph)-N(i)Pr(2)]Cl (8), respectively. Protonation of 5 was accomplished using HCl and gave the carbophosphazenium salt [ClPh(2)P=N-C(Ph)=N((t)Bu)H]Cl (6). In addition, the isolation of a rare 8-membered P(2)N(4)C(2) heterocycle [(Cl(3)P=N)ClPNC(Ph)NP(Cl)(2)NC(Ph)N] (9) from the reaction of PCl(5) and Li[PhC(NSiMe(3))(2)] is reported. Treatment of 9 with one equivalent of GaCl(3) led to the discovery of an unusual Lewis acid-induced ring contraction reaction whereby the (PNCN)(2) ring in 9 is converted into the novel 6-membered P(2)N(3)C heterocyclic adduct [(Cl(3)P=N)ClPNP(Cl)(2)NC(Ph)N].GaCl(3) (10) with concomitant release of PhCN. Structural characterization of compounds 1, 5, 6, and 8-10 by single-crystal X-ray diffraction is also provided.
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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 | 0.001 |
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".