Towards understanding of magnetic interactions within a series of tetrathiafulvalene- conjugated- verdazyl diradical cation system: a density funtional theory study
Bibliographic record
Abstract
The intramolecular magnetic exchange coupling constants (J) for a series of tetrathiafulvalene \n(TTF) and verdazyl diradical cations connected by a range of p conjugated linkers have been \ninvestigated by means of methodology based on unrestricted density functional theory. The \nmagnetic interaction between radicals is transmitted via p–electron conjugation for all considered \ncompounds. The calculation of J yields strong or medium ferromagnetic coupling interactions \n(in the range of 56 and 300 K) for diradical cations connected by linkers with an even number of \ncarbon atoms that are able to provide a spin polarization pathway, while antiferromagnetic \ncoupling is predicted when linkers with an odd number of carbon atoms are employed. The \ntopological analysis of spin density distributions have been used to reveal the effects of the spin \npolarization on both linkers and spin carriers. The absence of heteroatoms that impede the spin \npolarization pathway, and the existence of a unique spin polarization path instead of several \npossible competitive routes are factors which contribute to large positive J values favoring \nferromagnetic interactions between the two terminal p-radicals. The magnitude of J depends \nstrongly on the planarity of the molecular structure of the diradical cation since a more effective \norbital overlap between the two p-systems can be achieved. Hence, the dependence of J on the \ntorsion angle (y) of each spin carrier has been analyzed. In this respect, our findings show that \nthis geometrical distortion reduces largely the calculated J values for ferromagnetic couplings, \nleading to weak antiferromagnetic interactions for a torsion angle of 901
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 | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".