Gold(I) Macrocycles and Topologically Chiral [2]Catenanes
Bibliographic record
Abstract
The design and synthesis of a new type of topologically chiral [2]catenane is reported. The compounds are formed easily by self-assembly on reaction of the oligomeric digold(I) diacetylide precursor complex [[4-BrC(6)H(4)CH(4-C(6)H(4)OCH(2)CCAu)(2)](n)] with diphosphine ligands. Reactions with the diphosphines PP = bis(diphenylphosphinophoshino)acetylene, trans-1,2-bis(diphenylphosphino)ethylene, bis(diphenylphosphino)ethane, and 1,1'-bis(diphenylphosphino)ferrocene yield simple ring complexes [4-BrC(6)H(4)CH(4-C(6)H(4)OCH(2)CCAu)(2)(mu-PP)] as the only products, since the spacer groups in the diphosphines are not long enough or are too bulky to allow catenane formation. Reaction with PP = bis(diphenylphosphino)propane or bis(diphenylphosphino)butane gave [2]catenane complexes [[4-BrC(6)H(4)CH(4-C(6)H(4)OCH(2)CCAu)(2)(mu-PP)](2)], whose structures are confirmed crystallographically. The macrocyclic ring compounds have C(s) symmetry but, as a result of the presence of the unsymmetrical "hinge group" 4-BrC(6)H(4)CH, the [2]catenanes have C(2) symmetry and so are topologically chiral. In favorable cases, the formation of the [2]catenane can be proved by NMR spectroscopy since catenane formation leads to nonequivalence of most ring atoms. The formation of the [2]catenanes was successfully predicted based on the conformation of the precursor bis(phenol), and it is argued that the methods used should be more generally applicable to the synthesis of functionally substituted supermolecules of interest for application in molecular devices.
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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) | 0.000 | 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 | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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 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".