Macrocyclic Photoinitiator Based on Prism[5]arene Matching LEDs Light with Low Migration.

In this work, a naphthalene‐based macrocycle prism[5]arene (NP5OCH3) is developed as a novel kind of photoinitiator. When NP5OCH3 is irradiated under light, the bond between methylene and naphthalene can be quickly broken owning to the existence of ring tension. The macrocycle is cleaved to linear oligomer biradicals, which can effectively initiate the free radical photopolymerization of acrylate monomers. Compared with conventional photoinitiators, NP5OCH3 has strong light absorption in the wavelength range of 365–405 nm, so it can well match the environment‐friendly light‐emitting diodes (LEDs) light source to realize highly efficient initiation. In addition, there is no small molecule fragment generated during NP5OCH3 fracture, and the resulted linear oligomer biradicals can be immobilized in the polymer after initiating polymerization, so NP5OCH3 photoinitiators show much lower migration rate and cytotoxicity. Cleavable macrocycle prismarene may provide a new idea for the design of safe and efficient photoinitiators matching long wavelength light. [ABSTRACT FROM AUTHOR]