Synthesis of Intramolecularly Coordinated Aluminum and Gallium Compounds for the Preparation of [1]Ferrocenophanes
Bibliographic record
Abstract
Two different ligands equipped with pyridine donor moieties, (2-H 4 C 5 N)(Me 3 Si) 2 C (R′) and (2-H 4 C 5 N)(Me 3 Si)(Me)C (R″), were applied in the preparation of aluminum and gallium dihalides that could be employed in salt metathesis reactions with 1,1′-dilithioferrocene. R′GaCl 2 ( 1 ) was accessible from LiR′ and GaCl 3 (21%), whereas the respective aluminum compound R′AlCl 2 ( 3 Cl ) and its bromine analogue R′AlBr 2 ( 3 Br ) could only be prepared through the intermediate species R′AlMe 2 ( 2 ) by the addition of Me 3 SnCl and Br 2, respectively. An improved synthesis of the ligand precursor R″H, (2-H 4 C 5 N)(Me 3 Si)(Me)CH), is described. Attempted syntheses of R″AlX 2 starting from LiR″ and AlCl 3 or ClAlMe 2 gave the bis-ligand compounds R″ 2 AlCl ( 4 ) and R″ 2 AlMe ( 6 ), respectively. As deduced from proton NMR spectroscopy, the formation of 6 proceeded through the intermediate R″AlMe 2 ( 5 ) and was facilitated in the presence of tmeda. The formation of 4 and 6, respectively, is diastereospecific, as only rac isomers were formed ( R, R -Λ and S, S -Δ). Molecular structures of compounds 2, 3 Br, and 6 were determined by single-crystal X-ray analysis. Salt metathesis of the dihalides 1, 3 Cl, and 3 Br with 1,1′-dilithioferrocene gave the respective galla- and alumina[1]ferrocenes ( 7 and 8 ). Neither compound could be isolated and were only identified by 1 H NMR spectroscopy in reaction mixtures. Analytically pure polymers ( 7 n ) of low molecular weight were found and investigated by DLS ( M w = 8.3 ± 2.5 kDa; DP w = 17 ± 5).
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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) | 0.001 | 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 | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".