ABSTRACT Bromine‐substituted dyes, often used as a photosensitizer (PS) have limited utility due to their low photodurability. Here, we report a rotaxane strategy overcoming this photodurability problem. By employing a cooperative capture strategy with cucurbit6uril, we synthesized a rotaxane‐type PS in which a bromine‐substituted tolan derivative is irreversibly encapsulated within two heptakis(6‐ O ‐methyl)‐ β ‐cyclodextrin (6‐Me‐ β ‐CD) rings. 1 H NMR studies revealed the tail‐to‐tail orientation of the two 6‐Me‐ β ‐CD rings in the rotaxane. The CD rings worked as transparent shells to improve the photodurability of the internal tolan core. As a result, the 5rotaxane exhibited higher photosensitizing activity than the corresponding naked dibromotolan derivative. These results demonstrate that the rotaxane strategy can contribute to the development of new PSs.
Ichikawa et al. (2026) studied this question.