Dinitrogen Labile Coordination versus Four-Electron Reduction, THF Cleavage, and Fragmentation Promoted by a (calix-tetrapyrrole)Sm(II) Complex
Bibliographic record
Abstract
A divalent calix-tetrapyrrole Sm complex, {[(−CH 2 −) 5 ] 4 -calix-tetrapyrrole}Sm(THF)[Li(THF)] 2 [Li(THF) 2 ](μ 3 -Cl) ( 1 ), reacts with dinitrogen to reversibly form the labile dinuclear complex [{[(−CH 2 −) 5 ] 4 -calix-tetrapyrrole}Sm[Li(THF)] 3 (μ 3 -Cl)] 2 (μ 2 -N 2 )·2THF ( 2 ). Further attack on 2 by two additional molecules of 1 afforded four-electron reduction of the coordinated dinitrogen and formation of the novel trinuclear dinitrogen complex [{[(−CH 2 −) 5 ] 4 -calix-tetrapyrrole} 2 Sm 3 Li 2 ](μ 3 -N 2 )[Li(THF) 2 ]·THF ( 5 ). The formation of this species, where one calix-tetrapyrrole ligand was abstracted from one of the three samarium centers, is accompanied by formation of {[(−CH 2 −) 5 ] 4 -calix-tetrapyrrole}[Li(THF)] 4 ( 6 ) and of the trivalent {[(−CH 2 −) 5 ] 4 -calix-tetrapyrrole}Sm(Cl){[Li(THF)] 3 (μ 3 -Cl)} ( 7 ). A THF degradation reaction occurs in parallel to the dinitrogen fixation process. During the formation of 2, complex 1 also reacts with THF to afford another mononuclear divalent Sm complex, {[(−CH 2 −) 5 ] 4 -calix-tetrapyrrole}Sm(THF)Li 2 [Li(THF)](μ 3 -OCH CH 2 ) ( 3 ). This species contains an enolate fragment in the molecular backbone and shows no reactivity with N 2 . Recrystallization of 3 from THF did not eliminate the enolate fragment but afforded instead another divalent complex, {[(−CH 2 −) 5 ] 4 -calix-tetrapyrrole}Sm(THF) 2 {Li[Li(THF)] 2 }(μ 3 -OCH CH 2 )·THF ( 4 ), also unreactive toward N 2 . Finally a slow THF deoxygenation process occurs during the formation of 2 and 5, affording a dinuclear trivalent oxo derivative [{[(−CH 2 −) 5 ] 4 -calix-tetrapyrrole}Sm[Li(THF)] 3 (μ 3 -Cl)] 2 (μ-O) ( 8 ).
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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) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 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) | 0.019 | 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".