Cationic Thorium Alkyl Complexes of Rigid NON- and NNN-Donor Ligands: π-Arene Coordination as a Persistent Structural Motif
Bibliographic record
Abstract
Reaction of the neutral dialkyl complex [(XA 2 )Th(CH 2 SiMe 3 ) 2 ] { 1; XA 2 = 4,5-bis(2,6-diisopropylanilido)-2,7-di- tert -butyl-9,9-dimethylxanthene} with [CPh 3 ][B(C 6 F 5 ) 4 ] in benzene or toluene at room temperature resulted in the formation of [(XA 2 )Th(CH 2 SiMe 3 )(η 6 -arene)][B(C 6 F 5 ) 4 ] {arene = C 6 H 6 ( 5 ) and toluene ( 5B )}, which were characterized by 1 H, 13 C, and 2D NMR spectroscopy and by X-ray crystallography (for 5 ). In close analogy, reaction of [(XA 2 )Th(CH 2 Ph) 2 ] ( 3 ) with [CPh 3 ][B(C 6 F 5 ) 4 ] in toluene at room temperature resulted in the formation of 1 equiv of Ph 3 CCH 2 R (R = Ph) and precipitation of an insoluble orange-brown oil, which upon layering with hexanes yielded crystals of [(XA 2 )Th(η 2 -CH 2 Ph)(η 6 -C 6 H 5 Me)][B(C 6 F 5 ) 4 ] ( 6 ). NMR investigation of the reactions of 1 and 3 with substoichiometric amounts of [CPh 3 ][B(C 6 F 5 ) 4 ] provided no evidence for dinuclear monocation formation. By contrast, reaction of [(BDPP)Th(CH 2 Ph) 2 ] { 4; BDPP = 2,6-bis(2,6-diisopropylanilidomethyl)pyridine} with 0.5 equiv of [CPh 3 ][B(C 6 F 5 ) 4 ] resulted in the precipitation of an insoluble oil containing a mixture of a mononuclear and a dinuclear cation; the dinuclear cation was identified as [(BDPP)Th(η 2 -CH 2 Ph)(μ-η 1:η 6 -CH 2 Ph)Th(η 1 -CH 2 Ph)(BDPP)][B(C 6 F 5 ) 4 ] ( 7 ) by X-ray crystallography. Reaction of complex 3 with B(C 6 F 5 ) 3 resulted in the formation of [(XA 2 )Th(η 1 -CH 2 Ph)][η 6 -PhCH 2 B(C 6 F 5 ) 3 ] ( 9 ), which was characterized in solution by NMR spectroscopy. Complexes 5, 5B, and 6 are rare examples of arene solvent-separated ion pairs, complex 9 exists as a tight contact ion pair, and dinuclear 7 exhibits a unique benzyl ligand bridging mode. The structures of cations 5 − 7 and 9 highlight a pronounced tendency for these systems to engage in arene π-coordination.
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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".