What happens in the dark? Assessing the temporal control of photo‐mediated controlled radical polymerizations

Dolinski, Neil D.; Page, Zachariah A.; Discekici, Emre H.; Meis, David; Lee, In‐Hwan; Jones, Glen R.; Whitfield, Richard; Pan, Xiangcheng; McCarthy, Blaine G.; Shanmugam, Sivaprakash; Kottisch, Veronika; Fors, Brett P.; Boyer, Cyrille; Miyake, Garret M.; Matyjaszewski, Krzysztof; Haddleton, David M.; Alaniz, Javier Read de; Anastasaki, Athina; Hawker, Craig J.

doi:10.1002/pola.29247

Cited by 86 publications

(105 citation statements)

References 54 publications

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“…In the latter case, when the stimulus is removed the system behaves as in a normal ATRP, if no other reduction processes can occur. Thus, the residual Cu I /L is consumed by a few radical termination events . The amount of residual Cu I /L is lower for more active catalysts (i. e., higher K ATRP ), consequently less termination events and shorter times are needed to achieve a complete stop …”

Section: Effect Of Catalyst Activity On Temporal Control In Atrpmentioning

confidence: 99%

Why Do We Need More Active ATRP Catalysts?

Lorandi

Matyjaszewski

2019

Israel Journal of Chemistry

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Atom transfer radical polymerization (ATRP) is a staple technique for the preparation of polymers with well‐defined architecture. In ATRP, the catalyst governs the equilibrium between propagating radicals and dormant species, thus affecting the polymerization control for a range of monomers and transferable atoms employed in the process. The design and the use of highly active catalysts could diminish the amount of transition metal complexes, extend ATRP to less active monomers and give access to new chain‐end functionalities. At the same time, very active catalysts can be involved in formation of organometallic species. Herein, the role of the catalyst on the ATRP equilibrium is carefully elucidated, together with recent observations on the impact of the catalyst nature on formation of organometallic species and relevant side reactions. Based on this knowledge, a perspective on the benefits and challenges that derive from the use of highly active ATRP catalysts is presented.

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Section: Effect Of Catalyst Activity On Temporal Control In Atrpmentioning

confidence: 99%

Why Do We Need More Active ATRP Catalysts?

Lorandi

Matyjaszewski

2019

Israel Journal of Chemistry

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“…Thenecessity of oxygen is highlighted in Figure 2a,w herein no polymerization occurs in the presence of "inert" gases,such as CO 2 or N 2 .Surprisingly,pure oxygen afforded an increased polymerization rate (k app p,O 2 = 0.80 AE 0.06 vs. k app p,air = 0.31 AE 0.01) in comparison to air (ca. [20] In both cases,r eintroduction of air resulted in reactivation of polymerization without obvious changes to the polymerization rate (k app p,CO 2 = 0.37 AE 0.01 (before CO 2 )a nd 0.35 AE 0.01 (after air) and k app p,N 2 = 0.38 AE 0.01 (before N 2 )a nd 0.39 AE 0.02 (after air)). This acceleration mirrors the previously observed increase in rate with increasing TEA concentration and reinforces the essential role of oxygen gas.…”

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confidence: 92%

An Oxygen Paradox: Catalytic Use of Oxygen in Radical Photopolymerization

Zhang

Jung

et al. 2019

Angew Chem Int Ed

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Ap eculiar radical polymerization reaction is presented in which oxygen serves as ac ocatalyst, alongside triethylamine,t op rovide activation with light in the far-red (690 nm, 3mWcm À2 )o ft he PET-RAFT process in the presence of zinc(II) (2,3,7,8,12,13,17,18-octaethyl-5,10,15,20tetraphenylporphyrin) as photocatalyst. Apart from the ability to exert temporal control by switching the light on or off,t his system possesses the exciting capability of inducing temporal control by removal or reintroduction of oxygen. Furthermore, this multicomponent catalytic system was typified by controlled polymerizations of various acrylate and acrylamide monomers,w hicha ll resulted in well-defined polymers with low dispersity (< 1.2). The process displayed excellent living characteristics that were demonstrated through chain extensions and ar ange of degrees of polymerization (200-1600).Scheme 1. ZnOETPP-catalyzed PET-RAFT photopolymerization proceeds only in the presence of atertiary aliphatica mine and oxygen.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

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“…In the past few years, photochemical RDRP processes have gained significant attention as they combine the utility of RDRP with the more mild conditions and ambient temperatures associated with photochemical reactions . Photochemical processes also grant the ability to spatially and temporally control a polymerization, which is a significant challenge using the more traditional thermal methods of initiating radical polimerization …”

Section: Introductionmentioning

confidence: 99%

Using Kinetic Modeling and Experimental Data to Evaluate Mechanisms in PET‐RAFT

Kuhn

Allegrezza

Dougher

et al. 2019

Journal of Polymer Science

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Reversible deactivation radical polymerization (RDRP) techniques have become important tools for polymer chemists because they control the structure and are tolerant to functionality. Photoinduced polymerizations have seen a growing interest due to their mild conditions, as well as spatial and temporal control over the polymerization. Among these techniques, photoinduced electron/energy transfer reversible addition–fragmentation chain transfer polymerization (PET‐RAFT) is one of the most widely investigated. While PET‐RAFT is seen as an increasingly useful tool, there is still much to understand about the mechanism of this process. In particular, there are ongoing questions regarding the kinetic contribution of electron versus energy transfer. In order to better understand the mechanism, this work aims to use kinetic modeling along with experimental data to help determine the likelihood of the proposed mechanisms for the PET‐RAFT process using the trithiocarbonate‐mediated polymerization of methyl acrylate with fac‐tris[2‐phenylpyridinato‐C2,N]iridium(III) as a photocatalyst. Simulation data show that electron transfer without a corresponding reduction pathway cannot explain the experimental kinetics, while energy transfer offers a good fit to experimental data. © 2019 Wiley Periodicals, Inc. J. Polym. Sci. 2020, 58, 139–144

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What happens in the dark? Assessing the temporal control of photo‐mediated controlled radical polymerizations

Cited by 86 publications

References 54 publications

Why Do We Need More Active ATRP Catalysts?

Why Do We Need More Active ATRP Catalysts?

An Oxygen Paradox: Catalytic Use of Oxygen in Radical Photopolymerization

Using Kinetic Modeling and Experimental Data to Evaluate Mechanisms in PET‐RAFT

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