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

Abstract

Two novel supramolecular photoinitiators (supra-photoinitiators) based on the host−guest complexation of macrocycles (pillar[6]arene, P6; prism[5]arene, NP5) and diphenyl-iodonium salt (Iod) were fabricated. Under light irradiation, macrocycle P6 or NP5 could donate electrons to the guest molecule Iod, which generated highly active free radicals and cationic fragments to achieve efficient polymerization. Compared to a commercial activator, the electron transfer between macrocycles and Iod were under nondiffusion control, endowing a much higher photopolymerization rate and epoxy resin final conversion. In addition, the host−guest complexation of NP5 extended the initiating wavelength of Iod from ultrashort ultraviolet to near-ultraviolet, which could better match the environment-friendly LED light source. It is anticipated that a supra-photoinitiator may open a new route for designing novel photoinitiators with high performance.

per-Hydroxylated Prism[n]arenes: Supramolecularly Assisted Demethylation of Methoxy-Prism[5]arene

“…Recently, our group reported the prism[ n ]arenes 8 − 10 ( PrS[ n ] R , n = 5 and 6, R = Me, Et, n Pr, Figure 1 ), a novel class of macrocyclic hosts constituted by 1,5-methylene-bridged naphthalene units, obtained by one-pot condensation of 2,6-dimethoxynaphthalene and paraformaldehyde in the presence of TFA. 11 Very recently 12 the saucer[ n ]arene macrocycles were reported by the one-pot condensation of 2,7-dimethoxynaphthalene and paraformaldehyde. 12 …”

“…Oxatubarenes, naphtocages, zorbarenes, naphthotubes, calix[2]­naphth[2]­arenes, and prismarenes − are naphthalene-based emerging macrocycles, which are of great interest in supramolecular chemistry due to their peculiar structural properties and π-rich deep cavities. Recently, our group reported the prism­[ n ]­arenes − ( PrS­[ n ] R , n = 5 and 6, R = Me, Et, n Pr, Figure ), a novel class of macrocyclic hosts constituted by 1,5-methylene-bridged naphthalene units, obtained by one-pot condensation of 2,6-dimethoxy­naphthalene and paraformaldehyde in the presence of TFA . Very recently the saucer­[ n ]­arene macrocycles were reported by the one-pot condensation of 2,7-dimethoxynaphthalene and paraformaldehyde…”

“…Recently, our group reported the prism[n]arenes 8−10 (PrS[n] R , n = 5 and 6, R = Me, Et, nPr, Figure 1), a novel class of macrocyclic hosts constituted by 1,5-methylenebridged naphthalene units, obtained by one-pot condensation of 2,6-dimethoxynaphthalene and paraformaldehyde in the presence of TFA. 11 Very recently 12 the saucer[n]arene macrocycles were reported by the one-pot condensation of 2,7-dimethoxynaphthalene and paraformaldehyde. 12 Phenol and resorcinol-based macrocycles, such as calixarenes, 13 resorcinarenes, 14 and pillararenes, 15 have become highly studied and attractive synthetic hosts in supramolecular chemistry because of their easy functionalization.…”

Supramolecular Host‐Guest Interaction‐Driven Electrochemical Recognition for Pyrophosphate and Alkaline Phosphatase Analysis

“…have been used for the production of supramolecular complex with stimuliresponsive and selective abilities via amphiphilic, hydrogen bonding, electrostatic interactions, and so on. [30][31][32] Among these, cucurbit[n]urils (CB[n]s) have one hydrophobic cavity and two carbonyl-lined portals, which are a family of pumpkinshaped macrocyclic host molecules. [33,34] Why is there a strong host-guest complexation force between CB[n] and certain molecule?…”

“…Currently, plenty of macrocyclic host molecules (involving crown ethers, calix[n]arene, cyclophane, cucurbit[n]uril, cyclodextrin, pillar[n]arene, etc .) have been used for the production of supramolecular complex with stimuli‐responsive and selective abilities via amphiphilic, hydrogen bonding, electrostatic interactions, and so on [30–32] . Among these, cucurbit[n]urils (CB[n]s) have one hydrophobic cavity and two carbonyl‐lined portals, which are a family of pumpkin‐shaped macrocyclic host molecules [33,34] .…”