Coupling of CpCr(CO)<sub>3</sub>and Heterocyclic Dithiadiazolyl Radicals. Synthetic, X-ray Diffraction, Dynamic NMR, EPR, CV, and DFT Studies
Bibliographic record
Abstract
The reaction of the 1,2,3,5-dithiadiazolyls (4-R-C(6)H(4)CN(2)S(2))(2) (R = Me, 2a; Cl, 2b; OMe, 2c; and CF3, 2d) and (3-NC-5-tBu-C(6)H(3)CN(2)S(2))(2) (2e) with [CpCr(CO)(3)](2) (Cp = eta(5)-C(5)H(5)) (1) at ambient temperature respectively yielded the complexes CpCr(CO)(2)(eta(2)-S(2)N(2)CC(6)H(4)R) (R = 4-Me, 3a; 4-Cl, 3b; 4-OMe, 3c; and 4-CF(3), 3d) and CpCr(CO)(2)(eta(2)-S(2)N(2)CC(6)H(3)-3-(CN)-5-(tBu)) (3e) in 35-72% yields. The complexes 3c and 3d were also synthesized via a salt metathesis method from the reaction of NaCpCr(CO)(3) (1B) and the 1,2,3,5-dithiadiazolium chlorides 4-R-C(60H(4)CN(2)S(2)Cl (R = OMe, 8c; CF(3), 8d) with much lower yields of 6 and 20%, respectively. The complexes were characterized spectroscopically and also by single-crystal X-ray diffraction analysis. Cyclic voltammetry experiments were conducted on 3a-e, EPR spectra were obtained of one-electron-reduced forms of 3a-e, and variable temperature 1H NMR studies were carried out on complex 3d. Hybrid DFT calculations were performed on the model system [CpCr(CO)(2)S(2)N(2)CH] and comparisons are made with the reported CpCr(CO)(2)(pi-allyl) complexes.
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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) | 0.002 | 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".