Radical polymerization of radical‐labeled monomers: The triarylmethyl‐based radical monomer as an example

Abstract

Recent development of spin-labeled nitroxide-mediated polymerization (NMP) involving successful polymer preparation with high livingness and narrow dispersity in the presence of persistent trityl-based stable radicals attached to the initiators (90% recovery of a trityl radical signal after the polymerization) led us to the preparation of stable organic radical polymers based on trityl radical-substituted monomers using NMP as the method of polymerization despite the claims in the literature about its expected failure. Here, we present successful radical polymerization and NMP of a trityl radical-based tri-and monomonomer yielding more than 90% recovery of the trityl radical signal. EXPERIMENTAL GeneralInfrared (IR) spectra were recorded on Bruker Tensor 27 and Bruker Vector 22 FTIR spectrometers, and KBr pellets were used.Additional supporting information may be found in the online version of this article.

Synthesis, properties and chemical modification of a persistent triisopropylsilylethynyl substituted tri(9-anthryl)methyl radical

“…However, to use trityl-based persistent hydrocarbon radicals in this strategy, a functional group would need to be introduced before generating the radical (pre-modification) for avoiding rapid decomposition, 16 and the post-modification of the persistent radicals is still limited. 17 To explore this strategy, we examined reactions of radical 1 involving in situ removal of the silyl group using TBAF and subsequent [4+2] Diels–Alder reaction using tetraphenylcyclopentadienone (tetracyclone) (Scheme 3). We observed that this process leads to formation of the tetraphenylphenyl substituted TAntM radical 2 in 37% yield.…”

Synthesis of graft copolymers by combination of radical photopolymerization and iniferter process

“…Owing to its suitable activation–deactivation properties, trityl group has been employed for the synthesis of various complex macromolecular structures as a notable control agent . In an attempt to extend its practices and combinations with other polymerization techniques, herein a novel “grafting from” approach is reported.…”

New Variants of Nitroxide Mediated Polymerization

“…Indeed, in the literature, it was quoted [ 76 , 77 ]: “free-radical polymerization techniques cannot be used in the direct polymerization method” which is in sharp contrast with our claims concerning SL-NMP. Therefore, two types of trityl monomers were prepared—a trityl radical 9 carrying three acrylamides as monomer units and a trityl radical 10 carrying one unit of acrylamide as monomer—and were investigated in conventional polymerization and in NMP ( Figure 12 ) [ 78 ]. Depending on the experimental conditions, up to 90% of trityl radicals were recovered both in crude and purified materials.…”

“…Preparation of stable organic radical polymer (SORP) using conventional radical polymerization and NMP. Reprinted with the permission of Wiley from ref [78]…”