Entropy-driven ring-opening olefin metathesis polymerizations of macrocycles

Xue, Zheng; Mayer, M.

doi:10.1039/b913696g

Cited by 60 publications

(60 citation statements)

References 72 publications

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“…Methods of olefin‐containing macrocycle synthesis are discussed, as the route of preparation determines the ultimate reactivity of the monomer during ED‐ROMP. We build upon a 2009 review by Xue and Mayer by highlighting recent reports on ED‐ROMP to emphasize the usefulness of this technique for the preparation of polymers with unique backbone functionality, with prethreaded supramolecular guest molecules, and with well‐defined sequences, and other examples. Finally, we suggest future challenges in this rapidly expanding and impactful field.…”

Section: Introductionmentioning

confidence: 99%

“…Finally, as the ring size is increased even further, typically ≥14 atoms, there is minimal or negligible ring strain and atoms can adopt bonding configurations with near ideal bond angles and bond lengths . Instead of relying on the enthalpic gain of alleviating ring strain, ED‐ROMP is driven by two important forces: (1) a phenomenon known as the entropy of mixing; and (2) an increase in conformational entropy as the macrocycle is opened to its linear form . The first component describes the tendency of chemical reactions to progress toward mixtures of reactants and products in the absence of a significant enthalpic component.…”

Section: Introductionmentioning

confidence: 99%

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Recent developments in entropy‐driven ring‐opening metathesis polymerization: Mechanistic considerations, unique functionality, and sequence control

Pearce

Foster

O’Reilly

2019

J. Polym. Sci. Part A: Polym. Chem.

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Entropy‐driven ROMP (ED‐ROMP) involves polymerization of olefin‐containing macrocyclic monomers under entropically favorable conditions. Macrocycles can be prepared from a variety of interesting molecules which, when polymerized, impart unique functionality to the resulting polymer backbone such as degradable linkages, biological moieties, crystallizable groups, or supramolecular hosts. In addition, the sequence of atoms in the cyclic monomer is preserved within the polymer repeating units, allowing for facile preparation of sequence‐defined polymers. In this review article, we consider how the mechanism of ROMP applies to ED polymerizations, how olefinic macrocycles are synthesized, and how polymerization conditions can be tuned to maximize conversion. Recent works in the past 10 years are highlighted, with emphasis on methods which can be employed to achieve fast polymerization kinetics and/or selective head‐to‐tail regiochemistry, thus improving polymerization control. ED‐ROMP, with its unique capability to produce polymers with well‐defined polymer backbone microstructure, represents an essential complement to other, well‐established, metathesis methodologies such as ROMP. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1621–1634

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Recent developments in entropy‐driven ring‐opening metathesis polymerization: Mechanistic considerations, unique functionality, and sequence control

Pearce

Foster

O’Reilly

2019

J. Polym. Sci. Part A: Polym. Chem.

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“…Makrocyclische Olefin‐Monomere mit praktisch vernachlässigbarer Ringspannung können jedoch mittels der ROMP zu hohen Molekulargewichten polymerisiert werden 49. Diese Polymerisation wird als ED‐ROMP, d. h. Entropie‐getriebene Polymerisation bezeichnet 50…”

Section: Synthesestrategien Für Die Ppe‐plattformunclassified

Polyphosphoester: eine neue Plattform für abbaubare Polymere

Steinbach

Wurm

2015

Angewandte Chemie

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Polyphosphoester (PPEs) spielen eine wichtige Rolle in der Natur. Sie strukturieren und bestimmen das Leben in Form von Desoxy‐ und Ribonukleinsäure (DNA und RNA) und speichern chemische Energie in Organismen als Pyrophosphate. In der Polymerchemie hingegen dominieren nicht‐abbaubare Polyolefine und schwer abbaubare Polycarbonsäureester (PCEs), die heute in großem Maßstab industriell hergestellt werden. Neuere Arbeiten haben das Potenzial der PPEs für Anwendungen jenseits klassischer Flammschutzadditive aufgezeigt und ein schlüssiges Konzept vorgestellt, um diese Biopolymerklasse in modernen Anwendungen einzusetzen, die sich die Biokompatibilität und Abbaubarkeit sowie die Möglichkeit zunutze machen, die Polymereigenschaften an individuelle Bedürfnisse anzupassen.

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“…Surprisingly, macrocyclic olefin monomers with virtually negligible ring strain can undergo ROMP to yield polymers with high molecular weights 49. This polymerization is not enthalpy‐driven but entropy‐driven, and referred to as ED‐ROMP 50…”

Section: Synthetic Techniques For the Ppe Platformmentioning

confidence: 99%

The Mechanism of Hydrolysis of Aryldiazonium Ions Revisited: Marcus Theory vs. Canonical Variational Transition State Theory

et al. 2013

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Several models, theoretical levels and computational methods, all based on the canonical variational transition state approximation, have been used to predict both the experimental activation energies (ΔEexp≠) and the experimental activation free energies (ΔGexp≠) for the hydrolysis of aryldiazonium ions. It is demonstrated that the computation of activation energies (ΔE≠), instead of activation free energies (ΔG≠), agrees better with the corresponding experimental data, showing that the employed computational methods do not afford reliable entropic contributions to the free energy barriers in the case of the studied reaction. However, the most fitted computations of ΔE≠ were not able to clearly differentiate between the mechanisms proposed for this interesting reaction (SN1, SN2 and water cluster). In contrast, the use of the Marcus theory (hyperbolic‐cosine equation) instead of the canonical variational transition state theory leads to excellent agreement between the in‐water‐computed activation energies (ΔEwM≠) and the corresponding ΔEexp≠ values for the SN2 mechanism, but far beyond the limit of error for the SN1 process. The validity of the Marcus theory for the studied SN1 and SN2 reactions is ensured by the fact that both reactions can be described as SET processes. On the other hand, apparently compelling evidence against the SN2 mechanism, such as 13C KIEs and experimental observation of N2 scrambling, are also discussed and alternative explanations are proposed.

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Entropy-driven ring-opening olefin metathesis polymerizations of macrocycles

Cited by 60 publications

References 72 publications

Recent developments in entropy‐driven ring‐opening metathesis polymerization: Mechanistic considerations, unique functionality, and sequence control

Recent developments in entropy‐driven ring‐opening metathesis polymerization: Mechanistic considerations, unique functionality, and sequence control

Polyphosphoester: eine neue Plattform für abbaubare Polymere

The Mechanism of Hydrolysis of Aryldiazonium Ions Revisited: Marcus Theory vs. Canonical Variational Transition State Theory

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