Well-controlled Polymerization Research Articles

Potassium phenoxides bearing bulky yet flexible substituents as highly active catalysts for ring opening polymerization of biobased macrolactone of ethylene brassylate

Well-controlled and efficient ring opening polymerization of biobased ethylene brassylate is of great challenge due to its stainless ring structure that often results in inferior reactivities as well as the presence of two ester groups in the monomer that often lead to extensive intra-/inter- molecular transesterification side reactions. This report discloses a family of potassium phenoxide complexes that bear bulky yet flexible substituents. The bulky nature of the ligand could suppress undesired transesterification reactions, allowing the polymerization proceed in a well controlled manner, as revealed from the detailed kinetic studies that linear relationships between −ln(1-x) (x denotes the polymer yield) and the polymerization time and between molecular weights of the obtained polymers and polymer yields. The flexible substituents on the ligand allowed more monomer accessing to the active species, which eventually gave rise to TOFs in a range of 3604–3780 h−1, that were much higher than analogues in previous reports. Moreover, systematic evaluation of the polymerization behaviors demonstrated that the catalytic efficiency of the complexes was closely related to the steric nature of the metal center, increased the steric congestion would give rise to much lower monomer conversions. A plausible mechanism was proposed based on the polymerization results, and such a mechanism was further confirmed by NMR monitoring studies.

Torsional Strain Enabled Ring-Opening Polymerization towards Axially Chiral Semiaromatic Polyesters with Chemical Recyclability.

The development of new chemically recyclable polymers via monomer design would provide a transformative strategy to address the energy crisis and plastic pollution problem. Biaryl-fused cyclic esters were targeted to generate axially chiral polymers, which would impart new material performance. To overcome the non-polymerizability of the biaryl-fused monomer DBO, a cyclic ester Me-DBO installed with dimethyl substitution was prepared to enable its polymerizability via enhancing torsional strain. Impressively, Me-DBO readily went through well-controlled ring-opening polymerization, producing polymer P(Me-DBO) with high glass transition temperature (Tg >100 °C). Intriguingly, mixing these complementary enantiopure polymers containing axial chirality promoted a transformation from amorphous to crystalline material, affording a semicrystalline stereocomplex with a melting transition temperature more than 300 °C. P(Me-DBO) were capable of depolymerizing back to Me-DBO in high efficiency, highlighting an excellent recyclability.

Ring-opening polymerisation of alkyl-substituted ε-caprolactones: kinetic effects of substitution position

Alkyl-functional polycaprolactones were prepared via direct and well-controlled ring-opening polymerisation and the relationship between the substituent position and polymerisation rate was investigated.

Multibranched polymethacrylates by anionic grafting-from method via desilylation of poly(4-trimethylsilylmethylstyrene)

Abstract A benzyltrimethylsilane (BnTMS)/potassium tert-butoxide (t-BuOK) initiator system for anionic polymerization was applied to poly(4-trimethylsilylmethylstyrene) (PTMSMS) in the presence of 1,1-diphenylethylene (DPE) to construct polyanion macroinitiators and polymerize methacrylate monomers therefrom. Using this method, desilylation of PTMSMS was quantitatively processed and methacrylate monomers were polymerized from the macroinitiator. The obtained multibranched polymers had narrow molecular weight distributions, indicating the well-controlled polymerization of the monomers from the macroinitiator. Therefore, it was demonstrated that PTMSMS can be a suitable precursor for the preparation of multibranched polymers. Additionally, a sequential addition of methacrylate monomers to the polyanion macroinitiator lead to a core-shell multibranched polymer with a narrow molecular weight distribution.

Bimetallic Manganese Catalysts: A Route to Controlled and Switchable Polymerization of Lactones.

The sustainable solution to the environmental problem of polymeric materials calls for efficient and well-controlled ring-opening polymerization catalytic systems. Inspired by the highly reactive and stereospecific bimetallic catalysts, three kinds of bimetallic Salen-Mn catalysts supported by biaryl linking moieties are synthesized and applied to polymerization catalysis of lactide (LA) and ϵ-caprolactone (ϵ-CL) in this work. The polymerization is initiated in situ by the ring-opening of epoxide compounds, in which the ionic cocatalyst could accelerate the reaction process. The Mn-Mn coordination effect contributes to the higher activity and iso-selectivity towards LA compared to the mononuclear Salen-Mn catalyst. The reactivity and stereoselectivity are determined by the conformation of catalysts, specifically the Mn-Mn separation and dihedral angle. Finally, the CO2 -controlled switchable polymerizations are carried out with LA and ϵ-CL. The reversibility of the on-off switching operation is influenced by the combination between CO2 molecules and active species. The success in binuclear Salen-Mn catalysts not only expands the range of bimetallic catalyst analogues but also claims the promising potential of Mn-based catalysts in practical and theoretical research.

Development of Heterobimetallic Al/Mg Complexes for the Very Rapid Ring-Opening Polymerization of Lactides.

The successful architecture of active catalytic species with enhanced efficiencies is critical for the optimal exploitation of sustainable resources in industrially demanded processes. In this work, we describe the preparation of novel helical heterobimetallic Al/Mg-based complexes of the type [AlMe2(pbpamd-)MgR{κ1-O-(OC4H8O)}] [R = Et (1a), tBu (2a)] as potential catalysts. The design was performed through the sequential addition of the Al fragment to the ligand, followed by the Mg platform, resulting in a planar π-C2N2(sp2)-Al/Mg bridging core between metals. The new heterobimetallic species have been unambiguously characterized by single-crystal X-ray analysis. NOESY, DOSY, and EXSY NMR studies as well as density functional theory calculations corroborate both a rearrangement in solution to scorpionate complexes containing an unprecedented apical carbanion with a direct σ-C(sp3)-Al covalent bond named [{Mg(R)(pbpamd-) Al(Me)2}] [R = Et (1b), tBu (2b)] and an interconversion equilibrium between both isomers. We verified their utility and high efficiency as catalysts in the well-controlled ring-opening polymerization of the biorenewable l- and rac-lactide (LA) at 23 °C, reaching a remarkable turnover frequency value close to 25000 h-1 for rac-LA at this temperature and exerting a significant level of heteroselectivity (Pr = 0.80). Very interestingly, the kinetics demonstrate apparent first-order with respect to the catalyst and LA, which supports a synergic intramolecular cooperation between centers with electronic modulation among them.

Efficient Synthesis of Hydrolytically Degradable Block Copolymer Nanoparticles via Reverse Sequence Polymerization-Induced Self-Assembly in Aqueous Media.

Hydrolytically degradable block copolymer nanoparticles are prepared via reverse sequence polymerization-induced self-assembly (PISA) in aqueous media. This efficient protocol involves the reversible addition-fragmentation chain transfer (RAFT) polymerization of N,N'-dimethylacrylamide (DMAC) using a monofunctional or bifunctional trithiocarbonate-capped poly(ϵ-caprolactone) (PCL) precursor. DMAC monomer is employed as a co-solvent to solubilize the hydrophobic PCL chains. At an intermediate DMAC conversion of 20-60 %, the reaction mixture is diluted with water to 10-25 % w/w solids. The growing amphiphilic block copolymer chains undergo nucleation to form sterically-stabilized PCL-core nanoparticles with PDMAC coronas. 1 H NMR studies confirm more than 99 % DMAC conversion while gel permeation chromatography (GPC) studies indicate well-controlled RAFT polymerizations (Mw /Mn ≤1.30). Transmission electron microscopy (TEM) and dynamic light scattering (DLS) indicate spheres of 20-120 nm diameter. As expected, hydrolytic degradation occurs within days at 37 °C in either acidic or alkaline solution. Degradation is also observed in phosphate-buffered saline (PBS) (pH 7.4) at 37 °C. However, no degradation is detected over a three-month period when these nanoparticles are stored at 20 °C in deionized water (pH 6.7). Finally, PDMAC30 -PCL16 -PDMAC30 nanoparticles are briefly evaluated as a dispersant for an agrochemical formulation based on a broad-spectrum fungicide (azoxystrobin).

高分子末端の構造を自由に設計できる一置換アセチレン類の精密重合法の開発

Substituted polyacetylene derivatives are promising π-conjugated materials, which can be synthesized by polymerization of the corresponding substituted acetylenes by transition metal catalysis. Rhodium(I) complexes have been widely used for the polymerization of monosubstituted acetylenes such as phenylacetylene derivatives because they are functional group tolerant and provide cis-stereoregular polymers. There are some examples of well-controlled polymerization of phenylacetylene derivatives using well-defined rhodium(I) complexes as initiators. However, versatile design of polymer end structures is difficult in such known methods because initiators having various functional groups are not easily available. To overcome such a problem, we have developed a new method for well-controlled polymerization of phenylacetylene derivatives using a multicomponent catalytic system composed of bicyclo[2.2.1]hepta-2,5-diene-rhodium(I) chloride dimer [Rh(nbd)Cl]2, arylboronic acids, diphenylacetylene and 50% aqueous solution of KOH. This polymerization method showed a typical living nature, and structures derived from aryl boronic acids and diphenylacetylene were introduced to the initiating end of the obtained polymers. Moreover, functionalization of the polymer terminal end could be achieved by reactions of the living polymer terminus with α,β-unsaturated carbonyl compounds such as acrylates, and various telechelic poly(phenylacetylene)s were obtained. Novel 1,3,5-hexatrienylrhodium(I) complexes were isolated from the present multicomponent catalytic system, and their structures were identified. When [Rh(nbd)Cl]2 was replaced with hydroxy(1,5-cyclooctadiene) rhodium(I) dimer ([Rh(cod)OH]2) in the present catalytic system, cyclobutenylrhodium(I) complexes were exclusively obtained. These complexes provided insights into the initiation mechanism in the living polymerization. The present catalytic system was applied to the living polymerization of water-soluble phenylacetylene derivatives and non-conjugated monosubstituted acetylenes such as N-propargylamides.

Fully Oxygen-Tolerant Visible-Light-Induced ATRP of Acrylates in Water: Toward Synthesis of Protein-Polymer Hybrids.

Over the last decade, photoinduced ATRP techniques have been developed to harness the energy of light to generate radicals. Most of these methods require the use of UV light to initiate polymerization. However, UV light has several disadvantages: it can degrade proteins, damage DNA, cause undesirable side reactions, and has low penetration depth in reaction media. Recently, we demonstrated green-light-induced ATRP with dual catalysis, where eosin Y (EYH2) was used as an organic photoredox catalyst in conjunction with a copper complex. This dual catalysis proved to be highly efficient, allowing rapid and well-controlled aqueous polymerization of oligo(ethylene oxide) methyl ether methacrylate without the need for deoxygenation. Herein, we expanded this system to synthesize polyacrylates under biologically relevant conditions using CuII/Me6TREN (Me6TREN = tris[2-(dimethylamino)ethyl]amine) and EYH2 at ppm levels. Water-soluble oligo(ethylene oxide) methyl ether acrylate (average M n = 480, OEOA480) was polymerized in open reaction vessels under green light irradiation (520 nm). Despite continuous oxygen diffusion, high monomer conversions were achieved within 40 min, yielding polymers with narrow molecular weight distributions (1.17 ≤ D̵ ≤ 1.23) for a wide targeted DP range (50-800). In situ chain extension and block copolymerization confirmed the preserved chain end functionality. In addition, polymerization was triggered/halted by turning on/off a green light, showing temporal control. The optimized conditions also enabled controlled polymerization of various hydrophilic acrylate monomers, such as 2-hydroxyethyl acrylate, 2-(methylsulfinyl)ethyl acrylate), and zwitterionic carboxy betaine acrylate. Notably, the method allowed the synthesis of well-defined acrylate-based protein-polymer hybrids using a straightforward reaction setup without rigorous deoxygenation.

A Highly Active and Selective Zirconium-Based Catalyst System for the Industrial Production of Poly(lactic acid).

The biodegradable, aliphatic polyester poly(lactic acid), PLA, is a leading bio-based alternative to petrochemical-derived plastic materials across a range of applications. Widely reported in the available literature as a benchmark for PLA production via the bulk ring-opening polymerization of lactides is the use of divalent tin catalysts, and particularly tin(II) bis(2-ethylhexanoate). We present an alternative zirconium-based system that combines an inexpensive Group IV metal with the robustness, high activity, control, and designed compatibility with existing facilities and processes, that are required for industrial use. We have carried out a comprehensive kinetic study and applied a combined experimental and theoretical approach to understanding the mechanism by which the polymerization of lactide proceeds in the presence of this system. In the laboratory-scale (20 g) polymerization of recrystallized racemic d,l-lactide (rac-lactide), we have measured catalyst turnover frequencies up to at least 56,000 h-1, and confirmed the reported protocols' resistance toward undesirable epimerization, transesterification, and chain scission processes, deleterious to the properties of the polymer product. Further optimization and scale-up under industrial conditions have confirmed the relevance of the catalytic protocol to the commercial production of melt-polymerized PLA. We were able to undertake the efficient preparation of high-molecular-weight PLA on the 500-2000 g scale, via the selective and well-controlled polymerization of commercial polymer-grade l-lactide under challenging, industrially relevant conditions, and at metal concentrations as low as 8-12 ppm Zr by weight ([Zr] = 1.3 × 10-3 to 1.9 × 10-3 mol %). Under those conditions, a catalyst turnover number of at least 60,000 was attained, and the activity of the catalyst was comparable to that of tin(II) bis(2-ethylhexanoate).

On the Precise Determination of Molar Mass and Dispersity in Controlled Chain-Growth Polymerization: A Distribution Function-Based Strategy

Accurate information for the molar mass of polymers is a critical item in polymerization kinetic investigation and precision polymer synthesis. Size exclusion chromatography (SEC) is an irreplaceable technique to determine molar mass averages based on conventional calibration, which may nonetheless lead to inaccurate results due to the dissimilarity between the sample and the standard polymer. Herein, a facile distribution function-based strategy was proposed for the precise determination of molar mass average properties, aiming at rectifying the deviation of the standard-equivalent results from the true values. The number-average molar mass (Mn) can be recalculated involving the contribution of each molar mass component beyond the fundamental Mark–Houwink–Sakurada relation. In addition, the as-developed strategy is capable of converting the dispersity from the apparent to the true value, thereby re-estimating the uniformity of the rectified molar mass distribution. The strategy was successfully applied to the linear polymers with medium and low dispersities obtained by two well-controlled chain-growth polymerizations: reversible addition-fragmentation chain transfer polymerization and ring-opening metathesis polymerization, respectively. The rectified Mn closely match the benchmarks (i.e., absolute/theoretical Mn), showing a much higher accuracy than those conventionally calibrated SEC results. Attributing to the consideration of dispersity, the errors of the rectified results can be as low as zero. This work reduces the risk of experimental bias caused by conventionally calibrated SEC analysis to acquire precise mechanism insight and realistic polymerization process details.

Cu(0)-RDRP of 2-hydroxyethyl methacrylate in a non-polar solvent enables rapid synthesis of high-molecular weight homopolymers and direct access to amphiphilic copolymers

2-Hydroxyethyl methacrylate (HEMA) is an important functional monomer affording (co)polymers with numerous applications in different fields. Nevertheless, we still lack a reliable polymerization method for the synthesis of well-defined, high-molecular weight (MW) HEMA homopolymers, as well as for controlled copolymerization of unprotected HEMA with lipophilic comonomers. Herein, we report that rapid and well-controlled (co)polymerization of HEMA can be achieved via metallic copper-mediated reversible-deactivation radical polymerization (Cu(0)-RDRP) in a non-polar solvent (1,4-dioxane) using a chlorine-based initiation/catalytic system. With purified HEMA monomer, this protocol affords very well-defined (Ɖ ≤ 1.26) HEMA homopolymers in an unprecedently wide range of molecular weights from 10,000 to 500,000. Conversely, the structurally analogous bromine-based initiation/catalytic system leads to an uncontrolled polymerization. The use of a non-polar solvent enables, for the first time, a direct access to low-dispersity HEMA-rich copolymers with non-polar comonomers, including highly lipophilic ones. This is demonstrated on the successful copolymerization of HEMA with an equimolar amount of 2-ethylhexyl methacrylate and of lauryl methacrylate, yielding well-defined amphiphilic copolymers at quantitative conversion. This work significantly expands the application scope of the HEMA monomer and demonstrates for the first time that Cu(0)-RDRP in a non-polar solvent is applicable also to comparatively polar monomers.

Efficient and well-controlled ring opening polymerization of biobased ethylene brassylate by α-diimine FeCl3 catalysts via a coordination-insertion mechanism.

A highly efficient late-transition metal based catalytic system of α-diimine FeCl3 for well-controlled ring opening polymerization of a cheap and biobased macrolactone, ethylene brassylate (EB), is described herein. Proceeding via a coordination-insertion mechanism, such a catalytic system is capable of demonstrating unprecedented higher activities than previously reported organocatalysts or main-group metal based catalysts. Moreover, benefiting from the bulky nature of the α-diimine ligands, transesterification side reactions can be greatly suppressed, allowing the polymerization to proceed in a well-controlled living manner, as revealed from detailed kinetic studies. Additionally, such a catalytic system was also workable for ring opening copolymerization of EB and ε-caprolactone (ε-CL), giving the desired random copolymers with various compositions.

Synthesis and kinetic analysis of poly(N-acryloylmorpholine) brushes via surface initiated RAFT polymerization.

Polymer brushes are promising many applications as smart materials and biocompatible surfaces. Surface-initiated reversible addition-fragmentation chain transfer (RAFT) polymerization is one of the most effective techniques for synthesis of well-defined polymer brushes. Herein, a biocompatible, uniform and stable poly(N-acryloylmorpholine)-silicon hybrid system was achieved using surface-initiated RAFT polymerization. Evidence of a well-controlled surface-initiated RAFT polymerization was confirmed by a linear increase of number average molecular weight (Mn) with overall monomer conversions. Water contact angle, ellipsometry, X-ray photoelectron spectroscopy and atomic force microscopy verified the presence of poly(N-acryloylmorpholine) (poly(NAM)) on silicon wafers. The grafting density (σ) and the average distance between grafting points (D) were estimated to be 0.58 chains/nm2 and 1.5 nm, respectively. The ratio of D value to radius of gyration (Rg) value is smaller than 1 (D/2Rg < 1), which corresponds to the brush regime of all grafted poly(NAM) films.

End-functionalized diblock copolymers by mix and match of poly(2-oxazoline) and polyester building blocks

2-(4-(Iodomethyl)benzyl)isoindoline-1,3-dione was utilized as a protected amine-functionalized initiator for the cationic ring opening-polymerization (CROP) of 2-ethyl-2-oxazoline. As kinetic studies indicated a well-controlled polymerization, the CROP was terminated with sodium azide. Subsequent deprotection of the α-end group enabled successive attachment of a targeting ligand, e.g., retinoic acid or a proteogenic amino acid as a peptide model at the α-chain end. The heterotelechelic PEtOx were coupled to cyclooctyne end-functionalized polylactide, which was obtained by initiating the ring opening polymerization of l-lactide via a cyclooctyne based alcohol, utilizing strain-promoted azide-alkyne cycloaddidtion. In-depth characterization via mass spectrometry, 1H NMR spectroscopy, size exclusion chromatography, and infrared spectroscopy investigations verified the success of all synthetic steps and the preservation of retinoyl and leucine moieties also in the end-functionalized PEtOx-b-PLA block copolymers. Circumventing potential degradation of the polyester block during ligand attachment, the heterotelechelic PEtOx represents a universal building block useful for modular approaches towards tailored materials for nanomedicine.

The last challenge for living anionic polymerization of 1,3-cyclohexadiene with the s-butyllithium/cyclopentyl methyl ether system

A well-controlled anionic polymerization of 1,3-cyclohexadiene (1,3-CHD) with the alkyllithium (RLi)/ether system has been achieved for the first time. The type of ether was the predominant factor affecting the polymerization results. Optimization of the nucleophilicity and solubility of the initiator (system) and propagating species was also important for the polymerization reaction. An initiator system of sec -butyllithium ( s -BuLi)/cyclopentyl methyl ether (CPME) in toluene was found to be very effective for forming well-controlled polymer chains of poly(1,3-CHD), and living anionic polymerization was achieved. In this system, the polymer chains mainly consisted of 1,4-cyclohexadiene (1,4-CHD) units. It was confirmed that the s -BuLi/CPME system was a new example of living anionic polymerization of 1,3-CHD. • Living anionic polymerization of 1,3-CHD with the RLi/ether system has been achieved for the first time. • The s -BuLi/cyclopentyl methyl ether system is an excellent initiator system for living anionic polymerization of 1,3-CHD. • The combination of s -BuLi/cyclopentyl methyl ether is a new environmental-friendly and low-toxic initiator system. • This polymerization system enable the synthesis of well-controlled high molecular weight PCHD. • This system is the most effective for forming 1,4-CHD units in the well-controlled polymer chains of PCHD.

Novel Strategy for the Synthesis of Polymer/Pigment Hybrid Latex via Sulfur-Free RAFT-Mediated Emulsion Polymerization

Reversible addition–fragmentation chain transfer (RAFT) emulsion polymerization is a powerful tool for polymer encapsulation of pigment nanohybrids. Conventional RAFT emulsion polymers, however, contain sulfur residues that contribute to undesired odor and deleterious effects on final materials. Our strategy relies on an amphiphilic macromonomer poly(methacrylic acid-co-methyl methacrylate) P(MAA-co-MMA) with an ω-unsaturated end group synthesized in situ via cobalt(II)-mediated catalytic chain transfer polymerization (CCTP) at the surface of C.I. Pigment Blue 15:3 (PB) particles. Subsequently, these macromonomers are used as the living points to mediate the in situ sulfur-free RAFT (SF-RAFT) emulsion polymerization of monomers (butyl methacrylate (BMA) and butyl acrylate (BA)). It was found that a well-controlled polymerization process was achieved by semibatch SF-RAFT emulsion polymerization on the PB surface, as evidenced by the smooth increase in the molecular weight of polymer chains as the polymerization progressed and by transmission electron microscopy (TEM) results. Due to the sealing effect, these polymer/PB hybrid particles exhibited excellent colloidal stability in the aqueous phase. More importantly, film-forming hybrid particles with a soft P(BMA-co-BA) shell were successfully prepared in this work, which suggested that SF-RAFT-mediated polymerization may offer a useful alternative approach to traditional RAFT emulsion polymers for the preparation of organic/inorganic nanohybrids.

Cover Picture: Well‐Controlled Living Polymerization of N‐Propargylamides and Their Derivatives by Rhodium Catalysis (Angew. Chem. Int. Ed. 17/2022)

Well-controlled polymerization of non-conjugated acetylenes is a challenging subject. In their Research Article (e202117234), Tsuyoshi Taniguchi, Katsuhiro Maeda et al. report that unique heptaaryl-1,3,5-hexatrienylrhodium(I) complexes induce living polymerization of non-conjugated acetylenes such as N-propargylamides. This method enables controlling the molecular weights of the resultant polymers and the synthesis of telechelic polymers and block copolymers based on poly(N-propargylamide)s.

Investigation of morphology, crystal structure and property of ZnO/poly (methylstyrene-co-chloromethyl styrene) nanocomposite

A nanocomposite composed of ZnO and poly (methyl styrene-co-chloro methyl styrene) P (MSt-co-CMSt) by in situ polymerization method were prepared successfully. For this purpose, firstly, the zinc oxide surface was treated with 3-(trimethoxysilyl) propyl methacrylate (TMSPMA), a silane coupling agent, and following that this functionalization nano-ZnO particle was reacted with PMSt to prepare PMSt-grafted TMSPMA-ZnO. The resulting PMSt-grafted TMSPMA-ZnO was brominated with N-bromosuccinimide and coupled with 1-hydroxy-2, 2, 6, 6-tetramethyl-1-piperidinyloxy (TEMPO-OH) to produce an NMRP macroinitiator (PMSt-TEMPO/nano-ZnO). The well-controlled graft polymerization of 4-chloromethyl styrene (CMSt) with macroinitiators were carried out to produce nanoparticles based-ZnO (PMSt-co-PCMSt)/zinc oxide nanocomposite). Properties, crystal structure, and the morphology of (PMSt-co-PCMSt)/zinc oxide nanocomposite was studied using 1H-NMR, FT-IR, XRD, TGA, DSC, TEM, and UV-Vis spectroscopy. The results of FT-IR investigation and observations of TEM images represented clear and strong evidence for the preparation of PMSt and PMSt-co-PCMSt with spherical morphology of ZnO nanoparticles. The synthesized nanocomposites can be utilized a compound to attenuate the UV irradiation in the range of pointed wavelength.

Red-Light-Induced, Copper-Catalyzed Atom Transfer Radical Polymerization.

Despite advances in photochemical atom transfer radical polymerization (photoATRP), these systems often rely on the use of UV light for the activation/generation of the copper-based catalytic species. To circumvent the problems associated with the UV light, we developed a dual photoredox catalytic system to mediate photoinduced ATRP under red-light irradiation. The catalytic system is comprised of a Cu catalyst to control the polymerization via ATRP equilibrium and a photocatalyst, such as zinc(II) tetraphenylporphine or zinc(II) phthalocyanine, to generate the activator CuI species under red-light irradiation. In addition, this system showed oxygen tolerance due to the consumption of oxygen in the photoredox reactions, yielding well-controlled polymerizations without the need for deoxygenation processes.