Addition of Primary and Secondary Phosphines to Dinuclear Tantalum Hydrides: Synthesis of Phosphides and Phosphinidenes via P−H Bond Activation
Bibliographic record
Abstract
The dinuclear complex ( RPh [NPN]Ta) 2 (μ-H) 4 (where RPh [NPN] = [RP(CH 2 SiMe 2 NPh) 2 ] and R = Ph, Cy) shows remarkable reactivity with molecular nitrogen, producing the side-on end-on bound dinitrogen complex ( RPh [NPN]Ta) 2 (μ-η 1:η 2 -N 2 )(μ-H) 2 . This tantalum tetrahydride also promotes other small molecule activation. Addition of secondary phosphines HPR‘ 2 (R‘ = Ph, Cy) to ( RPh [NPN]Ta) 2 (μ-H) 4 accesses trihydride phosphide systems ( RPh [NPN]Ta) 2 (μ-H) 3 (μ-PR‘ 2 ). Addition of primary phosphines H 2 PR‘ ‘ (R‘ ‘ = Cy, Ad) gives bridging phosphinidene tantalum complexes ( RPh [NPN]Ta) 2 (μ-H) 2 (μ-PR‘ ‘). Molecular structures as determined by X-ray crystallography for the complexes ( PhPh [NPN]Ta) 2 (μ-H) 3 (μ-PCy 2 ) and ( CyPh [NPN]Ta) 2 (μ-H) 2 (μ-PAd) are presented. Isotopic labeling studies offer mechanistic insights into the reactivity of this tetrahydride system. Reaction of Cy 2 PH with ( CyPh [NPN]Ta) 2 (μ-D) 4, for instance, gives solely the monohydride dideuteride complex ( CyPh [NPN]Ta) 2 (μ-H)(μ-D) 2 (μ-PCy 2 ). This labeling study indicates that D 2 loss forms the reactive species, ( CyPh [NPN]Ta) 2 (μ-D) 2, which promotes small molecule activation. Addition of CyPH 2 to ( CyPh [NPN]Ta) 2 (μ-D) 4 gives a series of isotopomers, with an average composition of 0.67 H and 1.33 D, supporting a 1,2-H 2 elimination step to form the tantalum phosphinidenes. These results are tied into the general reactivity of ( RPh [NPN]Ta) 2 (μ-H) 4 .
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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 | 0.001 |
| 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) | 0.002 | 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".