Reduction of Titanium(IV)-Phosphinimide Complexes: Routes to Ti(III) Dimers, Ti(IV)-Metallacycles, and Ti(II) Species
Bibliographic record
Abstract
The redox chemistry of phosphinimide-containing group IV metal complexes has been investigated. Reaction of the simple phosphinimide species CpTi(NPR 3 )Cl 2 (R = Me 1, i -Pr 2 ) with Mg affords complexes formulated as [CpTiCl(μ-NPR 3 )] 2 (R = Me 3, i- Pr 4 ). In contrast, CpTi(NP t -Bu 3 )Cl 2 ( 5 ) is reduced by Mg to a putative Ti(II) species that can be intercepted by a variety of reagents including 2,3-dimethyl-1,3-butadiene, diphenylacetylene, phenylacetylene, bis(trimethylsilyl)acetylene, ethylene, and propylene to give monometallic metallacyclic complexes. In this fashion, the Ti(IV) metallacycles CpTi(NP t- Bu 3 )(CH 2 C(Me)C(Me)CH 2 ), 6, CpTi(NP t- Bu 3 )(CPh) 4, 7, CpTi(NP t- Bu 3 )(C(Ph)CHC(Ph)CH), 8, CpTi(NP t- Bu 3 )(η 2 -C 2 (SiMe 3 ) 2 ), 9, CpTi(NP t- Bu 3 )(CH 2 ) 4, 10, CpTi(NP t- Bu 3 )(CH 2 CHMe) 2, 15, and CpTi(NP t- Bu 3 )(CH 2 ) 2 (CPh) 2, 16, were prepared. Related intramolecular formation of metallacycle complexes was achieved upon reduction of Cp‘Ti( t- Bu 2 (2-C 6 H 4 Ph)PN)Cl 2 (Cp‘ = Cp 18, Cp* 19 ). The products [Cp‘Ti(NPtBu 2 (2-C 6 H 4 Ph)] (Cp‘ = Cp 20, Cp* 21 ) contained η 6 -interactions between Ti and the 2-phenyl substituent of the biphenyl unit. While Ti(II)-phosphinimide complexes have proven difficult to handle due to their reactivity, an unequivocal example of a Ti(II) species was obtained via reduction of Cp*Ti(NP t- Bu 3 )Cl 2 ( 11 ) with Mg in the presence of CO, affording the species Cp*Ti(NP t- Bu 3 )(CO) 2 ( 22 ). X-ray data for 4, 6, 7, 9, 10, 15, and 17 − 22 are reported.
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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) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.018 | 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".