The use of DOSY NMR for determining the size of rigid macrocycles

Diffusion ordered NMR spectroscopy (DOSY), in conjunction with the Stokes–Einstein equation, is a useful approach for assessing the size of a supramolecular architecture. While the method proves effective for estimating the size of approximately spherical assemblies, its use with large, rigid macrocycles is considered limited. Here, a series of rigid macrocycles are analysed by DOSY, and, using the modified Stokes–Einstein equation, the effects of increasing oblateness and exohedral modification on the rate of diffusion and predicted size of macrocycles are explored.