Functionalized and conformationally stable monkey saddles as building blocks for organic cages [data]
Organic cages are well-defined molecular entities with internal cavities that facilitate a variety of applications, including the separation and storage of chemicals, in particular of gases. In this dissertation, triptycene and so-called monkey saddles - truxene-based, negatively curved polycyclic a...
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| Dokumenttyp: | Datenbank Forschungsdaten |
| Sprache: | Englisch |
| Veröffentlicht: |
Heidelberg
Universität
2026-03-02
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| DOI: | 10.11588/DATA/IWWCMU |
| Schlagworte: | |
| Online-Zugang: | Verlag, kostenfrei, Volltext: https://doi.org/10.11588/DATA/IWWCMU Verlag, kostenfrei, Volltext: https://heidata.uni-heidelberg.de/dataset.xhtml?persistentId=doi:10.11588/DATA/IWWCMU 
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| Verfasserangaben: | Simone Felicia Ebel |
| Zusammenfassung: | Organic cages are well-defined molecular entities with internal cavities that facilitate a variety of applications, including the separation and storage of chemicals, in particular of gases. In this dissertation, triptycene and so-called monkey saddles - truxene-based, negatively curved polycyclic aromatic hydrocarbons in which three pentagons are fused with three octagons - were explored as building blocks for the construction of shape-persistent organic cages by alkyne metathesis. For triptycene, the previously prepared alkyne metathesis catalyst was initially tested on the generation of the respective hexadehydro[12]annulene cage subunit, and the reversibility of this reaction was scrutinized through scrambling experiments. For the monkey saddle, an alkyne metathesis catalyst screening was performed in collaboration with the Fürstner group at the Max-Planck-Institut für Kohlenforschung. Nevertheless, the racemic nature of the substrate likely impeded successful cage formation, while its configurational instability under alkyne metathesis reaction conditions simultaneously precluded the use of enantiopure material. This challenge motivated the second major goal of this thesis: the development of conformationally stable, functionalized monkey saddles. Building on the inversion stability observed for the so-called chromene monkey saddle, both post- and pre-functionalization strategies were pursued. Moreover, the results of different computational methods were benchmarked against experimental data to reliably predict the barrier heights of monkey saddles. This computational study further revealed that substitution at either the cyclooctatetraene or benzene units could significantly increase the inversion barrier. Consequently, diverse synthetic approaches were explored, whereby functionalization of the benzene rings was ultimately achieved, and the target compound’s racemization behavior was experimentally analyzed. The introduction of this specific substitution pattern also led to the isolation of a compound, in which the intramolecular construction of a dibenzofuran moiety forced the adjacent cyclooctatetraene ring into planarity. The structure was unambiguously confirmed by single-crystal X-ray diffraction. To gain deeper insight into the formation mechanism, deuterium labeling experiments and quantum-chemical calculations were carried out. Finally, the antiaromatic character of the planar cyclooctatetraene was investigated through a combination of 1H NMR spectroscopy and DFT studies. Overall, this dissertation explores avenues for the formation of alkyne-based cages and establishes essential synthetic and conceptual fundamentals for the design of conformationally stable, functionalized monkey saddles. These systems represent promising building blocks for the preparation of chiral three dimensional architectures reminiscent of carbon schwarzites. |
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| Beschreibung: | Gesehen am 02.03.2026 Gefördert durch: Deutsche Forschungsgemeinschaft: EXC-2082/1 – 390761711 (3D Matter Made to Order) |
| Beschreibung: | Online Resource |
| DOI: | 10.11588/DATA/IWWCMU |