Ligand protonation leads to highly fluorescent boronium cations
Bibliographic record
Abstract
Fluorophores that respond to external stimuli, such as changes in pH, have utility in bio-imaging and sensing applications. Almost all pH-responsive fluorophores rely on complex syntheses and the use of pH-responsive functional groups that are peripheral to the fluorophore framework. In this work, pH-responsive boron-containing heterocycles based on tridentate acyl pyridylhydrazone ligands were prepared. These non-emissive heterocycles were synthesized in three steps from inexpensive, commercially available reagents without the use of chromatography or air-sensitive reagents. Treatment with acid resulted in protonation of the boron-bound methylamine donor and efficient blue photoluminescence. Experimental and computational analysis revealed that protonation changed the geometric structure of the heterocycles and prevented photoluminescence quenching associated with photoinduced electron transfer. This work demonstrates a new approach for the design of fluorophores with potential applications in biological imaging.
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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".