Synthesis and solid state structures of 1,3-dihalo-1,3-<i>bis</i>(dialkylamino)propenium salts and related compounds
Bibliographic record
Abstract
1,3-dicholoro-1,3- bis(dialkylamino)propenium salts are prepared by condensing N, N,-dialkylamides with dichloromethylene dimethyliminium chloride (“Viehe's salt”). The products are versatile synthons and can be used to make a variety of ligand types. Here, we report the syntheses of a number of new propenium salts and provide comprehensive characterization data for some that have already been described. Additionally, we have prepared a series of related 1,3-dihalo-1,3- bis(dimethylamino)propenium salts via halogen exchange reactions (F through I). Finally, all of the compounds described, including Viehe's Salt and several hydrolysis products, have been characterized in the solid state using single crystal X-ray diffraction. The symmetrical cations [Me2NC(X)CHC(X)NMe2]+ were found to take one of two general structural forms. The first (X = H or F) is planar, presumably maximizing the delocalization within the backbone of the cation, while the second form is markedly twisted (X = Cl, Br or I). Calculations indicate that the latter develop increasingly positive regions of the electrostatic potential on the halide substituents, allowing cation/anion interactions via halogen bonding to dominate in the extended solids. The results of these studies illustrate the importance of the differing interionic interactions in a homologous series of small organic salts.
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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 | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".