https://doi.org/10.1351/goldbook.13983
Group bulky enough to prevent dethreading of a given macrocyclic component from a threading component or its translocation to another linear section of the threading component.
Notes:
- A stopper can be positioned at the end of the whole chain: end-group stopper, or along it: internal stopper. The latter is often a part of a rotaxane constitutional repeating unit.
- Whether a group functions as a stopper or not depends on the size of the macrocyclic component. Accordingly, when stoppers are mentioned, the macrocyclic component should also be mentioned. Examples of stoppers for \(\upbeta\)-cyclodextrin macrocyclic component are \(\ce{-CPh3}\) end-groups or \(\ce{-CPh2\bond{-}}\) groups included in constitutional repeating units:
- A more complex threading component may contain several linear sections due to the presence of branch points or internal large groups that prevent movement of macrocyclic components from one linear section to another.