Investigations of the mono- and dicycloaddition reactions of [SNS][MF<sub>6</sub>] (M = As, Sb) with the dinitriles NCC(O)CN and NCC(Cl)<sub>2</sub>CN — Energetics and the preference for [SNS]<sup>+</sup> dicycloaddition products in solution and solid state
Bibliographic record
Abstract
The stepwise symmetry-allowed cycloaddition reactions of [SNS]+ with the dinitriles NC–X–CN (X = CCl2, CO) were investigated. The reaction of [SNS]+ and dinitrile in 2:1 ratio yielded the dicycloaddition product quantitatively after 2 weeks (in situ 13C NMR). At a 1:1 ratio, mixtures of mono- and dicycloaddition products were obtained that could not be completely separated from one another. The energetics of the reaction were estimated in the gas phase, in solution (SO2 and CH2Cl2), and solid phases using DFT calculations (PBE0/6-311G*) and a "volume-based thermodynamics" approach for lattice enthalpies. Monocycloaddition products are stable in the gas phase and in solution with respect to disproportionation reactions, but in the solid state the disproportionation of 2 [NC–X–(CNSNS)][AsF6] into [X(CNSNS)2][AsF6]2 and NC–X–CN is strongly favored because of the higher lattice enthalpy of the 1:2 salt. In the gas phase, the second cycloaddition is endothermic because of the charge repulsion of the two positive charges, but in the solid state the reaction is strongly favored because of the lattice enthalpy gain on the formation of the 1:2 ([X(CNSNS)2][AsF6]2) from two 1:1 salts ([NC–X–(CNSNS)][AsF6] and [SNS][MF6]). The crystal structures of the dicycloaddition products [Cl2C(CNSNS)2][AsF6]2 and [OC(CNSNS)2][AsF6]2 and the monocycloaddition product [Cl2C(CNSNS)CN][AsF6] were obtained. In [Cl2C(CNSNS)CN][AsF6], the free nitrile groups interact with neighboring heterocycles further demonstrating that potential of free nitrile groups for introducing intermolecular interactions. [OC(CNSNS)2]2+ is a planar dication, which adopts the conformation with Sδ+···Oδ– contacts to optimize intramolecular electrostatic interactions.Key words: crystal structure, sulfur-nitrogen, 1,3,2,4-dithiadiazolyium, nitriles, cycloaddition, DFT calculations, thermodynamics, energetics.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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) | 0.002 | 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".