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Supramolecular cage encapsulation as a versatile tool for the experimental quantification of aromatic stacking interactions† †Electronic supplementary information (ESI) available: Experimental details on the competition experiments, DMCs and characterization of all new compounds. See DOI: 10.1039/c8
| Content Provider | Semantic Scholar |
|---|---|
| Author | Bravin, Carlo Licini, Giulia Hunter, Christopher A. Zonta, Cristiano |
| Copyright Year | 2019 |
| Abstract | The widespread presence of aromatic stacking interactions in chemical and biological systems, combined with their relatively small energetic contribution, have led to a plethora of theoretical and experimental studies for their quantification and rationalization. Typically, π-π aromatic interactions are studied as a function of substituents to gather information about the interaction mechanism. While experiments suggest that aromatic interactions are dominated by local electrostatic contacts between π-electron density and CH groups, theoretical work has raised the possibility that direct electrostatic interactions between local dipoles of the substituents may play a role. We describe a supramolecular cage that binds two aromatic carboxylates in a stacked geometry such that the aromatic substituents are remote in space. Chemical Double Mutant Cycles (DMCs) were used to measure fifteen different aromatic stacking interactions as a function of substituent (NMe2, OMe, Me, Cl and NO2). When both aromatic rings have electron-withdrawing nitro substituents, the interaction is attractive (-2.8 kJ mol-1) due to reduced π-electron repulsion. When both aromatic rings have electron-donating di-methylamino substituents, the interaction is repulsive (+2.0 kJ mol-1) due to increased π-electron repulsion. The results show that aromatic stacking interactions are dominated by short range electrostatic contacts rather than substituent dipole interactions. |
| Starting Page | 1466 |
| Ending Page | 1471 |
| Page Count | 6 |
| File Format | PDF HTM / HTML |
| DOI | 10.1039/c8sc04406f |
| PubMed reference number | 30809364 |
| Journal | Medline |
| Volume Number | 10 |
| Alternate Webpage(s) | https://pubs.rsc.org/en/content/articlepdf/2019/sc/c8sc04406f?page=search |
| Alternate Webpage(s) | https://doi.org/10.1039/c8sc04406f |
| Journal | Chemical science |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
