Synthesis of Rod-Like Dendronized Polymers Containing G4 and G5 Ester Dendrons via Macromonomer Approach by Living ROMP

Kim, Kyung Oh; Choi, Tae‐Lim

doi:10.1021/mz300032w

Cited by 55 publications

(58 citation statements)

References 49 publications

(25 reference statements)

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“…Once pseudo-ortho isomers shall be polymerized, harsh conditions become necessary and thus the high stability of HG2 catalyst (4) becomes mandatory. 36 In order to prove the quality of catalyst 6, two polymers with higher DPs were synthesized. High molecular weight polymers are accessible only by using isomers 2a and 2b (only short polymers are obtained when isomer 2c is used).…”

Section: Resultsmentioning

confidence: 99%

Reactivity Studies of Alkoxy-Substituted [2.2]Paracyclophane-1,9-dienes and Specific Coordination of the Monomer Repeating Unit during ROMP

Menk¹,

Mondeshki²,

Dudenko

et al. 2015

Macromolecules

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The polymerization of alkoxy-substituted [2.2]-paracyclophane-1,9-dienes via ring-opening metathesis polymerization (ROMP) to obtain soluble poly(pphenylenevinylene)s is a versatile method due to its living nature which enables the possibility of block copolymerization and end group modification. However, detailed studies on the reactivity behavior and the polymerization process of alkoxysubstituted [2.2]paracyclophane-1,9-dienes have not been reported so far. Herein we present a detailed study on the varying tendencies of the four isomers of dimethoxy-(2-ethylhexyloxy)-[2.2]paracyclophane-1,9-diene to undergo ROMP. Therefore, we carried out polymerization combining all individual isomers with five different metathesis catalysts and collected initiation and propagation kinetics for various combinations. Furthermore, we revealed a specific coordination of the monomer repeating unit to the catalyst during the polymerization process and succeeded to polymerize not only the pseudogeminal isomers but also one of the pseudo-ortho isomers.

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Section: Resultsmentioning

confidence: 99%

Reactivity Studies of Alkoxy-Substituted [2.2]Paracyclophane-1,9-dienes and Specific Coordination of the Monomer Repeating Unit during ROMP

Menk¹,

Mondeshki²,

Dudenko

et al. 2015

Macromolecules

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“…This result could be explained by a lower thermal stability of G3 and G3′ compared to G2 and HG2. 35 The polymers obtained using G2, G3, and G3′ displayed low dispersity values (Đ M ≤ 1.16) ( Figure 5A). When HG2 initiator was used, the SEC traces of the resulting polymers showed a shoulder toward higher molecular weights ( Figure 5E), which is consistent with a higher concentration of active species as explained previously.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

1,4-Polybutadienes with Pendant Hydroxyl Functionalities by ROMP: Synthetic and Mechanistic Insights

et al. 2015

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The reactivity of cis-3,4-bis(hydroxymethyl)cyclobutene derivatives bearing free and protected hydroxyl groups during ring-opening metathesis polymerization (ROMP) was investigated using ruthenium-based initiators. It was found that the ROMP of cis-4-benzyloxymethyl-3-hydroxymethylcyclobutene (1) using highly reactive initiators containing N-heterocyclic carbenes as nonlabile ligands leads to well-defined polymers while cis-3,4-bis(hydroxymethyl)cyclobutene (2) was reluctant to polymerize under the same conditions. Kinetic studies were performed to assess a number of critical reaction parameters: initiator structure, solvent, and temperature. The results demonstrate that Grubbs' second-and third-generation catalysts are the best initiators to prepare welldefined 1,4-polybutadienes containing simultaneously free and protected hydroxyl side groups with predictable molecular weights (up to 40 000 g mol −1 ) and narrow molecular weight distributions. Besides, low values of k p /k i (the ratio of the rate constant of propagation to the rate constant of initiation) were found for the ROMP of monomer 1 with Grubbs' second-generation catalyst in chloroform or THF as the solvent, demonstrating a living process. The so-obtained polymers having hydroxyl side groups are an ideal platform to prepare original well-defined graft copolymers through the grafting-from strategy. ■ INTRODUCTIONOver the past decade, ring-opening metathesis polymerization (ROMP) has emerged as a powerful tool to synthesize complex macromolecular architectures such as block and graft copolymers. 1,2 Thanks to ruthenium-based (Ru-based) catalysts, 3 a wide range of functionalized cyclic olefins can be polymerized by ROMP. 4 Norbornene and derivatives are the most common monomers studied in ROMP. 1,4 Norbornene has a sufficiently high ring strain (27.2 kcal mol −1 ) 5 to promote ROMP compared to inter-and intramolecular chain transfer reactions (secondary metathesis reactions). Furthermore, the steric hindrance around the double bonds of the growing polynorbornene chains allows to minimize the secondary metathesis reactions when high monomer conversion is reached, leading to polymers with controlled number-average molecular weights (M̅ n ) and low dispersities (Đ M ). ROMP of cyclobutene and functionalized derivativeswhich also present a high ring strain (30.6 kcal mol −1 ) 6 has been studied with a lesser extent compared to the ROMP of norbornene 1,2,4 and oxanorbornene 7 derivatives. However, this synthetic methodology constitutes the best strategy to synthesize strictly 1,4-polybutadiene. 8 Driven by our interest in developing efficient methodologies for the preparation of well-defined graft copolymers, our group previoulsy reported the ROMP of various cyclobutene-derived macromonomers that were prepared using various orthogonal processes such as atom transfer radical polymerization (ATRP), 9 reversible addition−fragmentation transfer (RAFT) polymerization, 10 click chemistry, 10,11 and organocatalyzed ring-opening polymerization. 12 The first study...

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“…Having demonstrated that the G1 functional dendron monomers are susceptible to homopolymerization with Grubbs' I and III initiators, albeit with relatively low

\overset{true‾}{X}

n , we next evaluated the ability to prepare homopolymers with significantly higher

\overset{true‾}{X}

n . For this series of experiments we focused exclusively on the bis pyrrole and protected sugar derivatives employing the Grubbs' III initiator with polymerizations performed in THF at 50 °C . Table gives a summary of the theoretical targeted

\overset{true‾}{M}

n values, together with the target

\overset{true‾}{X}

n values at quantitative conversion and the SEC measured number‐ and weight‐average molecular weights and Đ M values.…”

Section: Resultsmentioning

confidence: 99%

“…Importantly, and in the context of the work reported here, it has been demonstrated previously that metathesis polymerizations are suitable techniques for the preparation of dendronized (co)polymers via the macromonomer approach . For example, Rajaram et al reported the synthesis of AB diblock copolymers based on aryl ether dendron exo ‐norbornene macromonomers via ROMP with the Grubbs' III catalyst, RuCl 2 (3‐BrPy) 2 (ImMesH 2 )CHPh, to give materials of high‐number average molecular weight ( M n ) and low dispersity, as determined by multi‐angle laser light scattering.…”

Section: Introductionmentioning

confidence: 85%

Thiol‐Michael coupling and ring‐opening metathesis polymerization: facile access to functional exo‐7‐oxanorbornene dendron macromonomers

Liu

Burford

Lowe

2014

Polymer International

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Thiol‐Michael Coupling and ROMP: Facile Access to Functional exo‐7‐Oxanorbornene Dendron Macromonomers Nucleophile‐mediated thiol‐Michael coupling is employed to prepare a small library of functional thioether‐based dendron monomers from novel di‐ and tetra‐acrylate functional ring‐opening metathesis polymerization (ROMP)‐active exo‐7‐oxanorbornene‐based monomers. The ROMP (co)polymerization of these novel monomers is evaluated with Grubbs 1st and 3rd generation initators.

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Synthesis of Rod-Like Dendronized Polymers Containing G4 and G5 Ester Dendrons via Macromonomer Approach by Living ROMP

Cited by 55 publications

References 49 publications

Reactivity Studies of Alkoxy-Substituted [2.2]Paracyclophane-1,9-dienes and Specific Coordination of the Monomer Repeating Unit during ROMP

Reactivity Studies of Alkoxy-Substituted [2.2]Paracyclophane-1,9-dienes and Specific Coordination of the Monomer Repeating Unit during ROMP

1,4-Polybutadienes with Pendant Hydroxyl Functionalities by ROMP: Synthetic and Mechanistic Insights

Thiol‐Michael coupling and ring‐opening metathesis polymerization: facile access to functional exo‐7‐oxanorbornene dendron macromonomers

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