Titanium Complexes of Sterically Demanding Cage-Phosphinimide Ligands
Bibliographic record
Abstract
The known ligand PPh(C 6 H 4 O 3 Me 4 ) ( 1 ) and its analogue PCy(C 6 H 4 O 3 Me 4 ) ( 2 ) have been prepared. In the latter synthesis the diphosphine species (PCy) 2 (C 6 H 2 O 3 Me 4 ) ( 3 ) was also isolated as a minor product. Reaction of the cage phosphines 1 and 2 with Me 3 SiN 3 effected oxidation to the corresponding (trimethylsilyl)phosphinimines Me 3 SiNPR(C 6 H 4 O 3 Me 4 ) (R = Ph ( 4 ), Cy ( 5 )). Subsequent reactions afforded the titanium complexes CpTiCl 2 (NPR(C 6 H 4 O 3 Me 4 )) (R = Ph ( 6 ), Cy ( 7 )) and CpTiMe 2 (NPR(C 6 H 4 O 3 Me 4 )) (R = Ph ( 8 ), Cy ( 9 )). Preliminary screening for catalytic activity in ethylene polymerization employing either methylalumoxane (MAO) or [Ph 3 C][B(C 6 F 5 ) 4 ] as the activator showed minimal catalytic activity. These observations were probed via reactions of these complexes with AlMe 3, MAO, or [Ph 3 C][B(C 6 F 5 ) 4 ]. Reaction of 8 with AlMe 3 gave several products, one of which was fully characterized as the cage-rupture product CpTiMe 2 (NPCy(C 6 H 4 O 3 Me 5 )(μ-AlMe 2 )(AlMe 3 )) ( 10 ). A similar product is inferred by the spectroscopic monitoring of the reaction of 8 with MAO. In contrast, reaction of 2 with AlMe 3 resulted only in the formation of the adduct Me 3 AlPCy(C 6 H 4 O 3 Me 4 ) ( 11 ). Structural data are reported for 2, 3, 8, 10, and 11 .
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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 | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".