Pillar[6]arene: Light Cleaves Macrocycle to Linear Oligomer Biradical to Initiate Photopolymerization

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

“…[31][32][33][34][35][36][37][38][39][40] In our previous work, macrocyclic pillar [6]arene was first developed as photoinitiators and successfully used for initiating polymerization under the irradiation of mercury lamp light (295 nm). [41] Prismarene is a novel kind of macrocycle whose 2,6-dimethoxynaphthalene units are connected by methylene bridges, which was first synthesized in 2020. [42,43] In prismarene, there exists ring tension owing to the macrocyclic structure.…”

Nondiffusion-Controlled Photoelectron Transfer Induced by Host–Guest Complexes to Initiate Cationic Photopolymerization

“…31−33 Second, the macrocyclic P6/NP5 exhibited a much lower migration rate and cytotoxicity than other small-molecule photosensitizers, owing to the absence of small molecular fragment generation. 34,35 In addition, the host−guest complex extended the initiating wavelength of Iod from ultrashort ultraviolet to nearultraviolet, which could better match the environment-friendly LED light source. In this way, it would be proven that the supraphotoinitiators with a nondiffusion-controlled photoelectron transfer process could be developed for highly efficient photopolymerization.…”

“…At the same time, the newly presented peaks (H a , H b , H c , and H d ) on the 1 H NMR spectra proved that P6 would be broken to a straight chain (P6OC2H5-α/β-chain), which had been studied in our previous work. 34,35 The characteristic peaks of iodobenzene and other photodegradation products recovered from the round and wideshaped peaks to sharp and narrow peaks showed that the photodegradation products were released from the cavity of macrocycles and escaped from the reaction cage. NP5-Iod was shown to undergo similar light reactions under light irradiation in Figure S12.…”

“…First, in our paper, a photosensitizer (P6/NP5) and iodonium salt (Iod) are used to form a host–guest complex by supramolecular interaction. Thus, P6/NP5 could donate electrons to Iod under nondiffusion control, endowing a higher photopolymerization rate and epoxy resin final conversion than the multicomponents reaction process. − Second, the macrocyclic P6/NP5 exhibited a much lower migration rate and cytotoxicity than other small-molecule photosensitizers, owing to the absence of small molecular fragment generation. , In addition, the host–guest complex extended the initiating wavelength of Iod from ultrashort ultraviolet to near-ultraviolet, which could better match the environment-friendly LED light source. In this way, it would be proven that the supra-photoinitiators with a nondiffusion-controlled photoelectron transfer process could be developed for highly efficient photopolymerization.…”