Design of Sterically Demanding, Electron-Rich Carbene Ligands with the Perimidine Scaffold
Why this work is in the frame
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Bibliographic record
Abstract
A family of N, N ‘-disubstituted perimidinium cation salts were employed as precursors to persistent monomeric carbenes with novel molecular architectures and electronic structures. Depending on the substituents, reaction of these 1,3-disubstituted perimidinium cations with LiN(SiMe 3 ) 2 led either to deprotonation and generation of new carbenes or to enetetramines. In addition to spectroscopic characterization, crystallographic analysis of C 10 H 6 ( i PrN) 2 C ( 10 ), C 10 H 6 ( i PrN)(Me 3 CCH 2 N)C ( 11 ), {C 10 H 6 [N(3,5-Me 2 C 6 H 3 )] 2 C} 2 ( 13 ), and C 10 H 6 ( i PrN)(3,5-Me 2 C 6 H 3 N)C ( 14 ) definitively confirmed the nature of these species. The mixed benzyl/cycloheptyl-substituted carbene C 10 H 6 ( cyclo- C 7 H 13 N)(p-MeC 6 H 4 CH 2 N)C ( 17 ) was observed to undergo dimerization upon heating to yield both cis and trans isomers of the enetetramine {C 10 H 6 ( cyclo- C 7 H 13 N)( p- MeC 6 H 4 CH 2 N)C} 2, (17) 2 . Rhodium complexes of these perimidine-based carbenes were accessed via reactions with either monomeric carbene or enetetramine. Spectroscopic and crystallographic analysis of these rhodium−carbene complexes revealed the sterically demanding nature of the carbene ligands, which is manifested in the observation of hindered Rh−C carbene bond rotation and through % V bur measurements, and their exceptional electron-donating ability.
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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 | 0.000 | 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) | 0.002 | 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 it