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 <i>oblateness</i> and <i>exohedral modification</i> on the rate of diffusion and predicted size of macrocycles are explored.