Nucleophilic and Electrophilic Molybdenum Terminal Oxo Complexes by Coordination-Induced Bond Weakening of Hydroxo O–H Bonds
Bibliographic record
Abstract
The extent of coordination-induced bond weakening in aquo and hydroxo ligands bonded to a molybdenum(III) center complexed by a dianionic, pentadentate ligand system was probed by reacting the known complex (B 2 Pz 4 Py)Mo(III)-NTf 2, I, with degassed water or dry lithium hydroxide. The aquo adduct was not observed, but two LiNTf 2 -stabilized hydroxo complexes were fully characterized. Computational and experimental work showed that the O–H bond in these complexes was significantly weakened (to ≈57 kcal mol –1 ), such that these compounds could be used to form the diamagnetic, d 2 neutral terminal molybdenum oxo complex (B 2 Pz 4 Py)Mo(IV)O, 2, by hydrogen atom abstraction using the aryl oxyl reagent ArO• (Ar = 2,4,6-tri- tert -butylphenyl). Oxidation of the neutral hydroxo derivative further facilitated the production of 2 by significantly enhancing the acidity of the hydroxyl proton. Speciation in these processes was probed by electrochemical and chemical experiments. The terminal oxo complex 2 was smoothly oxidized by one electron to the cationic [(B 2 Pz 4 Py)Mo(V)O] + [A] − derivatives [2] + [A] – (A = NTf 2 or Al[OC(CF 3 ) 3 ] 4 depending on the oxidizing agent used). Both Mo(IV) and Mo(V) + oxo complexes were fully characterized with their nucleophilic and electrophilic reaction behavior probed by conducting reactions with the Lewis acid B(C 6 F 5 ) 3 and the Lewis base PPh 3 . Neutral oxo complex 2 reacts only with the Lewis acid, while the cationic [2] + [A] – reacts only with PPh 3, the former by adduct formation and the latter via phosphine oxidation.
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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".