Red-Emitting [Ru(bpy)<sub>2</sub>(N-N)]<sup>2+</sup> Photosensitizers: Emission from a Ruthenium(II) to 2,2′-Bipyridine <sup>3</sup>MLCT State in the Presence of Neutral Ancillary “Super Donor” Ligands
Bibliographic record
Abstract
The synthesis and characterization of a novel family of [Ru(II)(bpy)2(N-N)](PF6)2 (bpy = 2,2'-bypyridine) complexes are reported, where N-N = pyridine/pyrimidine/pyrazine functionalized in different positions with the electron-donating bicyclic hexahydropyrimidopyrimidine (hpp) unit. A series of bidentate ligands 1a-5a were synthesized in good to high yields (55-96%). The corresponding complexes 1b, 2b, and 5b were prepared in n-butanol, while complexes 3b and 4b were prepared in a mixture of n-butanol and water (1/1, v/v) in modest to good yields (23-76%). Both ligand and complex structures were fully characterized by a variety of techniques, including X-ray crystallography. In cyclic voltammetric studies, all the complexes exhibit a Ru(III/II) couple, which is ∼500 mV less positive than the Ru(III/II) couple in Ru(bpy)3(2+). The (1)MLCT and (3)MLCT states of all of the complexes (530-560 nm/732-745 nm) are shifted bathochromically in comparison to those of Ru(bpy)3(2+) (450 nm/620 nm). These values are in good agreement with DFT and TD-DFT calculations.
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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) | 0.001 | 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".