Aminoalkyl-Substituted Indenyl−Nickel Compounds: Tuning Reactivities as a Function of the Pendant, Hemilabile Moiety
Bibliographic record
Abstract
Indenyl ligands bearing three different aminoalkyl substituents have been used to prepare the complexes (Ind∧NR 2 )Ni(PPh 3 )Cl (Ind∧NR 2 = 2-(1-indenylmethyl)pyridine ( 1 ), N - (1-indenylethyl)pyrrolidine ( 2 ), and N -(1-indenylethyl)diisopropylamine ( 3 )). The solution NMR spectra of complexes 1 and 2 point to the existence of a dynamic process involving the reversible coordination of the pendant amine moieties to the Ni center, but no N−Ni interaction is evident in complex 3 . Abstraction of Cl - from the neutral precursors 1 − 3 yields the corresponding cationic derivatives [( η 3: η 1 -Ind∧NR 2 )Ni(PPh 3 )] + ( 4 − 6 ) wherein the amino tether is chelated to the nickel center. Complexes 1 − 5 have been isolated and fully characterized by multinuclear NMR spectroscopy and, in the case of 1 and 4, by single-crystal X-ray diffraction studies. The isolation of complex 6 is complicated by its partial conversion to the bis(phosphine) derivative [{ η 3: η 0 -IndCH 2 CH 2 N( i -Pr) 2 }Ni(PPh 3 ) 2 ] + ( 7 ). Studies on the displacement of the chelating amine moiety in 4 and 5 by dppe, PPh 3, and pyridine showed the pyridine moiety to be the least labile. Cyclic voltammetry studies have shown that the reduction potentials of the complexes vary as a function of the Ni−N interaction, the complexes bearing the NMe 2 moieties showing the strongest resistance to reduction. Olefin polymerization reactions also showed that the nature of the N-moiety has a considerable influence on the catalytic reactivity of the cationic complexes.
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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) | 0.001 | 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 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.023 | 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".