This article presents the synthesis and photophysical properties of a zwitterionic tetraazaacene derivative ( TAP ), which demonstrates exceptional efficiency as a photoinitiator for the free radical polymerization (FRP) of trimethylolpropane triacrylate (TMPTA) under 405 nm LED irradiation or sunlight exposure. TAP functions independently as a photoinitiator by generating azaheterocyclic and carbon‐centered radicals, thereby initiating the polymerization process. Its performance is further enhanced when combined with coinitiators such as an iodonium salt (Iod) and ethyl 4‐dimethylaminobenzoate (EDB) in a three‐component system. Upon photoexcitation, an electron transfer reaction occurs from TAP to Iod, producing TAP radical cations and phenyl radicals, while EDB regenerates TAP and forms EDB radicals. This synergistic combination achieves approximately 60% acrylate conversion and significantly increases the initial polymerization rate under both LED and sunlight conditions, outperforming two‐component photoinitiating systems. These findings highlight the potential of TAP as a foundation for developing new zwitterionic photoinitiators capable of polymerizing (meth)acrylate monomers using natural sunlight.
Mouhoubi et al. (Wed,) studied this question.