Unusual Redox Chemistry of Ytterbium Carbazole–Bis(oxazoline) Compounds: Oxidative Coupling of Primary Phosphines by an Ytterbium Carbazole–Bis(oxazoline) Dialkyl
Bibliographic record
Abstract
The 1,8-bis(4′,4′-dimethyloxazolin-2′-yl)-3,6-di- tert -butylcarbazole anion (Czx) forms monomeric, six-coordinate halide complexes of Yb(II), (Czx)Yb(X)(THF) 2 (X = I ( 2 ), Cl ( 3 )), by metathesis of YbX 2 with NaCzx ( 1 ) or Na/Hg reduction of (Czx)Yb(Cl) 2 (THF). The crystal structure of 1 reveals a polymeric chain structure in which the oxazoline ring bridges to the Na + of an adjacent unit. The iodo complex 2 serves as a precursor to divalent silylamide, alkyl, and phosphide complexes, (Czx)Yb(X)(THF) n ( 4, X = N(SiMe 3 ) 2, n = 1; 5, X = CH(SiMe 3 ) 2, n = 1; 7a, X = 2,4,6-Me 3 C 6 H 2 PH, n = 2; 7b, X = 2,4,6-Pr i 3 C 6 H 2 PH, n = 2). The X-ray structure of 4 reveals a distorted-trigonal-bipyramidal geometry with the Czx ligand occupying two axial sites and one equatorial site in a pseudo- mer coordination mode. In contrast to the typical metathesis chemistry observed with LiCH(SiMe 3 ) 2, an unusual oxidation occurs when 2 or 3 is treated with LiCH 2 SiMe 3 to generate the previously isolated trivalent alkyl (Czx)Yb(CH 2 SiMe 3 ) 2 . Trivalent Yb complexes with the Czx ligand also display unusual redox chemistry: rapid reduction to the Yb(II) phosphides 7a, b is observed on treatment of mer,cis -(Czx)Yb(Cl) 2 (THF) with ArPH – Na + ( 6a, b ) or, equivalently, on treatment of (Czx)Yb(CH 2 SiMe 3 ) 2 with ArPH 2 . In both cases, oxidative coupling of the phosphide or phosphine was observed to form meso - and rac -biphosphines, ArPH–PHAr (Ar = 2,4,6-Me 3 C 6 H 2 ( 9a ), 2,4,6-Pr i 3 C 6 H 2 ( 9b )).
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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) | 0.002 | 0.001 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.016 | 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".