A rigid molecular balance for measuring face-to-face arene-arene interactions.

A new molecular balance was developed to measure face-to-face arene-arene interactions. The balance adopts distinct folded and unfolded conformations due to restricted rotation about a C aryl-N imide bond. In the folded conformer, the rigid bicyclic framework enforces an offset face-to-face geometry to the exclusion of edge-to-face geometries, which was verified by X-ray crystallography. Measurement of the folded to unfolded ratio yields accurate values for the arene-arene interaction in a range of different solvents.