Proton Sponge Phosphanes: Reversibly Chargeable Ligands for ESI‐MS Analysis
Bibliographic record
Abstract
Abstract Proton sponge phosphanes are unusual ligands in that they possess two basic sites with very different functions: the phosphorus binds to a metal center, while the 1,8‐bis(dimethylamino)naphthalene binds protons strongly. Both groups are selective for their target, and the binding of the proton iseasily reversible by controlling the pH of the solution. Proton sponge phosphanes therefore make useful chargeable ligands for the purposes of electrospray ionization mass spectrometric analysis of the complexes in which they are bound. However, where the 1,8‐bis(dimethylamino)naphthalene is functionalized with the phosphane is critical, and the 1‐dimethylamino group can become involved in binding to the metal when diphenylphosphane is in the 2‐position. This behavior is undesirable from the point of view of keeping proton and metal binding segregated, and we introduce an efficient synthesis of the 4‐substituted proton sponge phosphane in which the two functional groups are on opposite sides of the naphthalene ring. This precaution solves the problem of the molecule acting as a bidentate ligand, but caution is still needed when using the ligand, because ionization pathways such as halide dissociation to form [M – X]+ ions and oxidation of electron‐rich metal complexes to form [M]·+ can be competitive with protonation.
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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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.001 |
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".