Carbon−Carbon Bond Formation Using Yttrium(III) and the Lanthanide Elements
Bibliographic record
Abstract
The synthesis and characterization of a series of yttrium and lanthanide complexes that incorporate the macrocyclic bis(amidophosphine) ligand PhP(CH 2 SiMe 2 NSiMe 2 CH 2 ) 2 PPh, [P 2 N 2 ], are described. The starting materials, {[P 2 N 2 ]M} 2 (μ-Cl) 2, (M = Y, Sm, Ho, Yb, Lu), are prepared by the reaction of syn -Li 2 (dioxane)[P 2 N 2 ] with MCl 3 (THF) 3 in toluene. The reactivity of these complexes toward PhLi and other arylating agents is dependent on the size of the M 3+ ion. M = Y and Ho undergo C−C bond formation reactions to give biphenyldiide compounds {[P 2 N 2 ]M} 2 {μ-η 6:η 6 ‘ -(C 6 H 5 ) 2 } and {[P 2 N 2 ]Y} 2 {μ-η 6:η 6 ‘ -(C 6 H 4 - p- Ph) 2 }. These have been structurally characterized and show the biphenyl dianion bridging two [P 2 N 2 ]M fragments. These [P 2 N 2 ]M fragments migrate over the bridging ligand's π-surface on the NMR time scale. M = Yb yields the paramagnetic monophenyl derivative [P 2 N 2 ]Yb(C 6 H 5 ), where the Yb center is coordinatively unsaturated and resides in a distorted square-pyramidal environment. M = Lu results in a mixture of “ate” complexes of the formulation “[P 2 N 2 ]LuPh·LiCl”, as evidenced by 7 Li NMR. However, the biphenyl product {[P 2 N 2 ]Lu} 2 {μ-η 6:η 6 ‘ -(C 6 H 5 ) 2 } can be synthesized via a reductive route. The presence of THF was found to be deleterious to the coupling reaction; in this case, the THF adduct [P 2 N 2 ]Y(C 6 H 4 -p- Me)(THF) was isolated and structurally characterized. The mechanism for the C−C bond formation reaction is described based on the isolation of these yttrium and lanthanide complexes.
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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 | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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 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".