Periodic Trends in Reactions of Benzene Clusters of Transition Metal Cations, M(C<sub>6</sub>H<sub>6</sub>)<sub>1,2</sub><sup>+</sup>, with Molecular Oxygen
Bibliographic record
Abstract
Mono- and bis-adducts of benzene of the type M(C 6 H 6 ) 1,2 + have been generated in the gas phase with first-, second-, and third-row transition metal cations, and their reactivities toward molecular oxygen have been measured using an inductively coupled plasma/selected-ion flow tube (ICP/SIFT) tandem mass spectrometer. Trends in reactivity were identified for the metal cation adducts across and down the periodic table. The intrinsic effect of the benzene ligand(s) on the reactivity of the bare metal cations was determined through comparisons with earlier results obtained for the bare metal ions. Molecular oxygen activation by early transition metal cations is preserved in the presence of one benzene ligand but almost disappears in the presence of two benzene molecules. The rate coefficients for O 2 addition to late transition metal−benzene adducts are enhanced by up to 4 orders of magnitude in the presence of benzene. Thermochemical information is derived from the occurrence or absence of ligand-switching or metal-abstraction reactions. Oxidation of the benzene ligand itself was observed to be mediated by the transition metal cations V +, Cr +, Fe +, Co +, and Re + and appeared to result from simultaneous activation of C−H, C−C, and O−O bonds. Catalytic oxidation of the benzene ring observed in the presence of Fe +, Cr +, and Co + is postulated to result in the production of catechol.
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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".