Supramolecular balance: using cooperativity to amplify weak interactions.

Gathering precise knowledge on weak supramolecular interactions is difficult yet is of utmost importance for numerous scientific fields, including catalysis, crystal engineering, ligand binding, and protein folding. We report on a combined theoretical and experimental approach showing that it is possible to vastly improve the sensitivity of current methods to probe weak supramolecular interactions in solution. The concept consists of using a supramolecular platform involving a highly cooperative configurational transition, the perturbation of which (by the modification of the molecular building blocks) can be monitored in a temperature scanning experiment. We tested this concept with a particular bisurea platform, and our first results show that it is possible to detect the presence of interaction differences as low as 60 J/mol, which may be due to steric repulsion between vinyl and alkyl groups or may be the result of solvation effects.