Sulfate as a ligand in ruthenium(II) and (III) ammines
Bibliographic record
Abstract
The trans-[RuSO 4 (NH 3 ) 4 (L)]Cl complexes, (L = nicotinamide (nia), L-histidine (L-hist), 4-picoline (4-pic), 4-chloropyridine (4-Clpy), isonicotinamide (isn), pyrazine (pyz), 4-aminopyridine (4-NH 2 py), 4-cyanopyridine (4-CNpy), pyridine (py), imidazole (Him), and water (H 2 O)), were characterized by elemental analysis cyclic voltammetry, UV-vis, IR, and electron paramagnetic resonance spectroscopies. From the four ν (SO 4 2 ) observed only ν 3 and ν 4 split in two bands each for the sulfate unidentate coordination. The values of Δ/ξ parameters, extracted from g values, allow us to write the following order of increasing π-donation ability: pyz < (py, 4-CNpy, 4-Clpy. 4-pic, isn, nia) < Him < L-hist < 4-NH 2 py. The intense absorption in the 317-347 nm (ε ~ 2.3-5.6 × 10 3 M -1 cm -1 ) region was tentatively assigned to sulfate-to-metal charge transfer (LMCT) and the absorption in the range of 230-270 nm (ε ~ 2 - 6 × 10 3 M -1 cm -1 ) assigned to an internal (IL) π-π * transition in the heterocyclic ligands. The rate for the sulfate aquation in trans-[RuSO 4 (NH 3 ) 4 L] 0 complexes was evaluated through chronopotentiometric measurements and are in the 2.6 s -1 (chloropyridine) to 20 s -1 (pyrazine) range. The SO 4 2 is aquated in trans-[Ru III SO 4 (NH 3 ) 4 (4-pic)]Cl at the specific rate constant of (1.4 ± 0.4) × 10 -5 s -1 , which is very much slower than in trans-[Ru II SO 4 (NH 3 ) 4 (4-pic)] (5.4 s -1 ). The X-ray crystal structure data show that the Ru-Cl (2.3444(9) Å) and Ru-NH 3 (2.100(2) Å) mean distances in trans-[RuCl(NH 3 ) 4 (4-pic)]Cl 2 ·H 2 O are similar to the ones observed in other tetraammineruthenium(III) complexes.Key words: ruthenium, sulfate, ammines.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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) | 0.000 | 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 teacher head, 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".