Structure and Reactivity of Neutral and Cationic <i>trans</i>-<i>N</i>,<i>N</i><b>′</b>-Dibenzylcyclam Zirconium Alkyl Complexes
Bibliographic record
Abstract
Reactions of (Bn 2 Cyclam)ZrCl 2 ( 1 ) (where Bn 2 Cyclam = trans -N,N′(PhCH 2 ) 2 Cyclam) with appropriate alkylating reagents produced (Bn 2 Cyclam)ZrR 2 (R = Me ( 2 ), CH 2 Ph ( 3 ), n Bu ( 4 ), CCPh ( 5 )). Activation of the ortho C−H bond of the two macrocycle benzyl substituents in complexes 2, 3, and 4 was thermally induced, leading to the formation of a bis( ortho -metalated) complex, ((C 6 H 4 CH 2 ) 2 Cyclam)Zr ( 6 ). This reaction proceeds along with RH elimination and converts the original dianionic tetracoordinated cyclam in a tetraanionic hexacoordinated ligand where two new Zr−C Ph bonds complete the metal sphere. Treatment of 6 with one equivalent of HC≡CPh led to ((C 6 H 4 CH 2 )BnCyclam)Zr(CCPh) ( 7 ) via protonation of one Zr−C Ph bond by phenylacethylene. Further reaction of 7 with an excess of HC≡CPh led to 5 . The reactions of 2 and 3 with B(C 6 F 5 ) 3 are strongly solvent dependent. Solvent-stabilized cationic species of formula [(Bn 2 Cyclam)ZrR(Solv)][RB(C 6 F 5 ) 3 ] were obtained from reactions of 2 in CD 2 Cl 2 ( 10 ) or d 8 -THF ( 12 ) and from 3 in d 8 -THF ( 9 ). The reactions of 3 in CD 2 Cl 2 or d 8 -toluene gave [(Bn 2 Cyclam)Zr(η 2 -CH 2 Ph)][ PhCH 2 B(C 6 F 5 ) 3 ] ( 8 ). Finally, the reaction of 2 in d 8 -toluene led to [(Bn 2 Cyclam)Zr(C 6 F 5 ){CH 2 B(C 6 F 5 ) 2 }] ( 14 ); the precursor of the latter is the zwitterionic [(Bn 2 Cyclam)Zr(CH 3 ){CH 3 B(C 6 F 5 ) 3 }] ( 11 ), which then undergoes methane elimination and C 6 F 5 migration from boron to zirconium. The mechanism of this reaction was studied by DFT and revealed that (i) methane elimination is assisted by one alpha-agostic C−H bond and (ii) migration of the C 6 F 5 ring is supported by one bridging fluorine bond between the zirconium and one of the C 6 F 5 rings that remains bonded to boron.
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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 | 0.000 |
| 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) | 0.007 | 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".