Getting tubed: mechanical bond in endohedral derivatives of carbon nanotubes?

We present a brief overview of some of the most prominent examples of encapsulation of molecules inside carbon nanotubes. We then relate them to mechanically interlocked molecules, and in particular rotaxanes, by examining the most prominent features of the mechanical bond (topology, dynamic properties, and stability) and comparing them to those of endohedral derivatives of nanotubes. Our analysis shows that there is a surprisingly clear link between these two apparently disparate species.