Steric Repulsion Induced Conformational Switch in Supramolecular Structures
| Autor: | Ligia C. Gomes-da-Silva, Mathias O. Senge, John E. O'Brien, Karolis Norvaiša, Brendan Twamley, Sophie Maguire, Claire L. Donohoe |
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| Rok vydání: | 2021 |
| Předmět: |
Steric effects
chemistry.chemical_classification Atropisomer Porphyrins 010405 organic chemistry Chemistry Organic Chemistry Supramolecular chemistry Molecular Conformation General Chemistry 010402 general chemistry 01 natural sciences Small molecule Porphyrin Catalysis 0104 chemical sciences Supramolecular polymers Crystallography chemistry.chemical_compound Strain engineering Intramolecular force Solvents |
| Zdroj: | Chemistry Europe |
| ISSN: | 1521-3765 |
| Popis: | Inspired by the rigidified architecture of 'picket-fence' systems, we propose a strategy utilizing strain to impose intramolecular tension in already peripherally overcrowded structures leading to selective atropisomeric conversion. Employing this approach, tuneable shape-persistent porphyrin conformations were acquired exhibiting distinctive supramolecular nanostructures based on the orientation of the peripheral groups. The intrinsic assemblies driven by non-covalent bonding interactions form supramolecular polymers while encapsulating small molecules in parallel channels or solvent-accessible voids. The developed molecular strain engineering methodologies combined with synthetic approaches have allowed the introduction of the pivalate units creating a highly strained molecular skeleton. Changes in the absorption spectrum indicated the presence of severe steric repulsions between the peripheral groups which were confirmed by single crystal X-ray analysis. To release the steric strain introduced by the peripheral units, thermal equilibration strategies were used to selectively convert the most abundant atropisomer to the desirable minor one. |
| Databáze: | OpenAIRE |
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