Expanded Functionality of Polymers Prepared Using Metal-Free Ring-Opening Metathesis Polymerization

Abstract

Photoredox-mediated metal-free ring-opening metathesis polymerization (MF-ROMP) is an alternative to traditional metal-mediated ROMP that avoids the use of transition metal initiators while also enabling temporal control over the polymerization. Herein, we explore the effect of various additives on the success of the polymerization in order to optimize reaction protocols and identify new functionalized monomers that can be utilized in MF-ROMP. The use of protected alcohol monomers allows for homo- and copolymers to be prepared that contain functionality beyond simple alkyl groups. Several other functional groups are also tolerated to varying degrees and offer insight into future directions for expansion of monomer scope.

Heteroatom‐Doped Carbon Dots (CDs) as a Class of Metal‐Free Photocatalysts for PET‐RAFT Polymerization under Visible Light and Sunlight

“…[1] Recently,t he integration of photo-mediated synthesis with reversible-deactivation radical polymerization (RDRP), including nitroxide-mediated polymerization (NMP), atom-transfer radical polymerization (ATRP), and reversible addition-fragmentation chain-transfer (RAFT) polymerization, is as ignificant advancement in this field. [3] So far, in this field, great progress has been made in the groups led by Hawker and Fors, [4] Matyjaszewski, [5] Yagci, [6] Miyake, [7] Boyer, [8][9][10] Qiao, [11] Haddleton and Anastasaki, [12] Johnson, [13,14] Boydston, [15] Egap, [16] and many others. [3] So far, in this field, great progress has been made in the groups led by Hawker and Fors, [4] Matyjaszewski, [5] Yagci, [6] Miyake, [7] Boyer, [8][9][10] Qiao, [11] Haddleton and Anastasaki, [12] Johnson, [13,14] Boydston, [15] Egap, [16] and many others.…”

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Ak ey challenge of photoregulated living radical polymerization is developing efficient and robust photocatalysts.Now carbon dots (CDs) have been exploited for the first time as metal-free photocatalysts for visible-light-regulated reversible addition-fragmentation chain-transfer (RAFT) polymerization. [3] So far, in this field, great progress has been made in the groups led by Hawker and Fors, [4] Matyjaszewski, [5] Yagci, [6] Miyake, [7] Boyer, [8][9][10] Qiao, [11] Haddleton and Anastasaki, [12] Johnson, [13,14] Boydston, [15] Egap, [16] and many others. PET-RAFT polymerization of various monomers with temporal control, narrowdispersity ( % 1.04), and chain-endfidelity was achieved.Besides,itwas demonstrated that the CD-catalyzed PET-RAFT polymerization was effectively performed under natural solar irradiation.

Inspired by the solar-driven biosynthesis of proteins with high chain end fidelity and sequence control, macromolecular research has been focused on the exploitation of light to regulate modern polymer synthesis for ab etter control over the polymerization process.

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Remote control grubbs catalysts that modulate ring‐opening metathesis polymerizations

“…For example, the authors reported that the ROMP of norbornene could be toggled between “on” (i.e., relatively active) and “off” (i.e., relatively inactive) states multiple times without detriment. Subsequent studies from the same group have extended the utility of photoredox‐mediated, metal‐free ROMP to other monomers, including functionalized norbornenes, dicyclopentadiene, and dihydrodicyclopentadiene …”

Living Cationic Polymerization of Vinyl Ethers through a Photoinduced Radical Oxidation/Addition/Deactivation Sequence

“…A similar photoinduced redox strategy has been applied to azide-alkyne click reactions, which also utilize Cu I species. The promising field of photoiniated controlled polymerization is further extended by the ring-opening metathesis polymerization reported by Boydston et al [17] Although photoinitiated cationic polymerization has been known and industrially applied for decades, [18] possibilities to develop new variations to adapt this process to CLP have scarcely been investigated. [13] The Boyer group has also elegantly extended this concept to RAFT process.…”

“…Various photoactive compounds, such as photoinitiators, [8] dyes, [9] mesoporous structures, [10] and nanoparticles, [11] have been successfully employed the electron transfer and reduction of Cu II to Cu I , which in turn catalyzes the ATRP process. The promising field of photoiniated controlled polymerization is further extended by the ring-opening metathesis polymerization reported by Boydston et al [17] Although photoinitiated cationic polymerization has been known and industrially applied for decades, [18] possibilities to develop new variations to adapt this process to CLP have scarcely been investigated. [12] Photoinduced electron-transfer-promoted ATRP has also been reported for Ir(ppy) 3 -based systems by Hawker and co-workers.…”