Ring-Opening Metathesis Polymerization of Norbornene Using Vinylic Ethers as Chain-Transfer Agents:  Highly Selective Synthesis of Monofunctional Macroinitiators for Atom Transfer Radical Polymerization

The involvement of a catalytic metal vinylidene species was proposed for the first time in 1986 to explain the regioselective formation of vinyl carbamates directly from terminal alkynes, carbon dioxide, and amines. Since this initial report, various metal vinylidenes and allenylidenes, which are key activation intermediates, have proved extremely useful for many alkyne transformations. They have contributed to the rational design of new catalytic reactions. This 20th anniversary is a suitable occasion to present the advancement of organometallic vinylidenes and allenylidenes in catalysis.

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“…[188] The molecular weight was controlled by addition of vinyl ether and vinyl thioether as chain-transfer reagents. [187,189] …”

Section: Alkyne Polymerization and Ring-opening Olefin Metathesis Witmentioning

confidence: 99%

Metal Vinylidenes and Allenylidenes in Catalysis: Applications in Anti‐Markovnikov Additions to Terminal Alkynes and Alkene Metathesis

2006

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“…4 Utilizing ROMP, end-functionalized macromolecular precursors for block copolymer synthesis may be prepared by (1) using functionalized metathesis catalysts, [5][6][7] (2) terminating a living ROMP reaction with an appropriately functionalized reagent (e.g., ethyl vinyl ether derivatives for Ru-based catalysts), [8][9][10] or (3) introducing a functionalized acyclic chain transfer agent (CTA) with a cyclic monomer. 11 Linear block copolymers have been prepared from mechanistically incompatible monomers by combining ROMP of cyclic olefins with atom-transfer radical polymerization (ATRP), 9,10,[12][13][14][15] reversible addition-fragmentation chaintransfer (RAFT) polymerization, 16 and anionic polymerization. 17 Likewise, hydroxyl-terminal polymers are effective initiators for the ring-opening polymerization (ROP) of cyclic esters to produce block polymers.…”

Section: Introductionmentioning

confidence: 99%

Combining Ring-Opening Metathesis Polymerization and Cyclic Ester Ring-Opening Polymerization To Form ABA Triblock Copolymers from 1,5-Cyclooctadiene andd,l-Lactide

Pitet

Hillmyer

2009

Macromolecules

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ABA triblock copolymers were synthesized by combining ring-opening metathesis polymerization (ROMP) of 1,5-cyclooctadiene (COD) with ring-opening polymerization of D,L-lactide. Hydroxyl-functionalized telechelic polyCOD was prepared by taking advantage of chain transfer during ROMP of COD using the acyclic chain transfer agent cis-1,4-diacetoxy-2-butene. These hydroxy-terminated macroinitiators were used as initiators for the polymerization of lactide to form a series of triblock copolymers with compositions in the range 0.24 e f PLA e 0.89 and molecular weights ranging from 22 to 196 kg mol -1 . The ordered-state morphologies of the triblocks were determined using small-angle X-ray scattering; well-ordered microstructures were observed for several samples, in accordance with the predicted dependence of morphology on composition. The mechanical properties of these materials were also investigated by performing tensile measurements; the triblocks were considerably tougher than poly(D,L-lactide), most markedly in samples with low polyCOD midblock content.

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“…Previously reported methods for synthesizing block copolymers by combining well-defined ruthenium initiated ROMP and PS, have produced materials that possess a rather broad molecular weight distribution. 28,13 For instance the ROMP of norbornene derivatives b a initiated by ruthenium initiators was used to create macroinitiators that initiated the ATRP of styrene, resulting in the synthesis of block copolymers of styrene with a PDI of 2.70. 29 The molecular weight distributions of the block copolymer synthesized with our methodology thus compare very favourably with PS-PNB block copolymers synthesized via other routes.…”

Section: Resultsmentioning

confidence: 99%

Block Copolymers by the Conversion of Living Lithium Initiated Anionic Polymerization into Living Ruthenium ROMP

Castle

Khosravi

2006

Macromolecules

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. (2006) 'Block copolymers by the conversion of living lithium initiated anionic polymerization into living ruthenium ROMP. ', Macromolecules., 39 (17). pp. 5639-5645.Further information on publisher's website: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. ABSTRACT: This paper describes a method for the synthesis of well-defined AB block copolymers, where one block is synthesized via anionic polymerization initiated with alkyllithium compounds, and one by ring opening metathesis polymerization (ROMP) using well-defined ruthenium macroinitiators.This methodology was demonstrated by copolymerizing styrene with norbornene derivatives.Polystyrene was synthesized via living anionic polymerization initiated by sec-butyllithium, and functionalized to form macromonomers. These were used as precursors to well-defined ruthenium 2 macroinitiators, the macromonomers being converted by an alkylidene exchange reaction with ruthenium propylidene initiator RuCl 2 (=CHEt)(PCy 3 ) 2 . These macroinitiators were used to initiate the ROMP of various norbornene derivatives in order to synthesize well-defined block copolymers with narrow molecular weight distributions.

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Ring-Opening Metathesis Polymerization of Norbornene Using Vinylic Ethers as Chain-Transfer Agents: Highly Selective Synthesis of Monofunctional Macroinitiators for Atom Transfer Radical Polymerization

Cited by 51 publications

References 16 publications

Metal Vinylidenes and Allenylidenes in Catalysis: Applications in Anti‐Markovnikov Additions to Terminal Alkynes and Alkene Metathesis

Metal Vinylidenes and Allenylidenes in Catalysis: Applications in Anti‐Markovnikov Additions to Terminal Alkynes and Alkene Metathesis

Combining Ring-Opening Metathesis Polymerization and Cyclic Ester Ring-Opening Polymerization To Form ABA Triblock Copolymers from 1,5-Cyclooctadiene andd,l-Lactide

Block Copolymers by the Conversion of Living Lithium Initiated Anionic Polymerization into Living Ruthenium ROMP

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