A set of 27- to 39-membered pyridine macrocycles 2 and 3 has been synthesized by Williamson ethersynthesis or ring-closingmetathesis. The pyridines are 2,6-disubstituted to allow endo interactions. In addition to the length, also the nature of the aliphatic chain was varied: saturated (2) and unsaturated (3).
A [2]rotaxaneshuttle for (light-driven) protontransport has been designed and synthesized. The rotaxane contains a macrocyclic ring that carries a pyridine nitrogen atom as a basic center to bind and to transport a proton. The axis includes an amide binding site for the macrocycle and a positive charge in close vicinity. Upon protonation of the pyridine nitrogen atom, the hydrogen bond is broken