Metal- and Ligation-Dependent Fragmentation of [M(1,10-Phenanthroline)<sub>1,2,3</sub>]<sup>2+</sup> Cations with M = Mn, Fe, Co, Ni, Cu, and Zn: Comparison between the Gas Phase and Solution
Bibliographic record
Abstract
The core ions [ML(n)]2+ with n = 1-3, where L = 1,10-phenanthroline and M is a first-row transition metal, have been successfully transferred from aqueous solution into the gas phase by electrospraying and then probed for their stabilities by collision-induced dissociation in a triple quadrupole mass spectrometer. The triply ligated metal dications [ML3]2+ were observed to dissociate by the extrusion of a neutral ligand, while ligand loss from both [ML2]2+ and [ML]2+ was accompanied by electron transfer. Comparisons are provided between gas-phase stabilities and stabilities for ligand loss measured in aqueous solution at 298 K. The measured onset for ligand loss from [ML3]2+ is quite insensitive to the metal, while a distinct stability order has been reported for aqueous solution. Low level density functional theory (DFT) calculations predict an intrinsic stability order for loss of ligand from [ML2]2+, but it differs from that in aqueous solution. Substantial agreement was obtained for the stability order for the loss of ligand from [ML]2+ deduced from onset energies measured for charge separation, computed with DFT, and reported for aqueous solution where hydration seems less decisive in influencing this stability order. A qualitative potential-energy diagram is presented that allows the energy for charge separation to be related to the energy for neutral ligand loss from [ML]2+ and shows that IE(M+) is decisive in determining the intrinsic stability order for loss of ligand from [ML]2+.
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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".