Reduction of hafnium(IV) complexes in the presence of molecular nitrogen: Attempts to form dinitrogen complexes of the heaviest group 4 element
Bibliographic record
Abstract
The reaction of [P 2 N 2 ]Li 2 (dioxane) 2 with HfCl 4 (THF) 2 (where [P 2 N 2 ] = PhP(CH 2 SiMe 2 NSiMe 2 CH 2 ) 2 PPh) results in the formation of the hafnium dichloride complex [P 2 N 2 ]HfCl 2 (1). The behaviour of 1 as a potential precursor in the generation of a dinitrogen coordination complex is described. Reduction of 1 with potassium-graphite (C 8 K), under dinitrogen, under a variety of conditions led to a number of products, one of which is the dinuclear derivative with bridging P-phenyl groups that has the general formula {[P 2 N 2 ]Hf} 2 (2). Reduction of the hafnium diiodide [P 2 N 2 ]HfI 2 (3) prepared via the reaction of 1 with excess Me 3 SiI with C 8 K results in the formation of ([P 2 N 2 ]Hf) 2 (µ-η 2 :η 2 -N 2 ) (4) as the major product of the reaction, while {[P 2 N 2 ]Hf} 2 (2) and [P 2 N 2 ]Hf(C 7 H 8 ) (5) appear to be minor products. Reaction of 1 with 2 equiv of MeMgCl gives [P 2 N 2 ]HfMe 2 (6), which, upon exposure to an atmosphere of H 2 , gives the hafnium tetrahydride {[P 2 N 2 ]Hf} 2 (m-H) 4 (7).Key words: hafnium, dinitrogen, reduction, coordination chemistry, hydride, mixed donor ligands.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.001 | 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 teacher head, 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".