Ring-opening polymerization of norbornene by a living tungsten alkylidene complex

Schrock, Richard R.; Feldman, Jerald; Cannizzo, Louis F.; Grubbs, Robert H.

doi:10.1021/ma00171a053

Cited by 248 publications

(99 citation statements)

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“…Tungsten (W) chloride-based catalysts polymerize strained cyclic olefins in a nonliving fashion. On the other hand, well-defined W-carbene complex 5 (Scheme 7) catalyzes the living ROMP of norbornene, 15 and W-based catalysts are tolerant to ester groups. The initiation and propagation rate constants have been examined in the ROMP of variously substituted ester-containing norbornenes using W-carbene complex 6.…”

Section: Intermolecular Chain Transfermentioning

confidence: 99%

Recent advances in ring-opening metathesis polymerization, and application to synthesis of functional materials

Sutthasupa

Shiotsuki

Sanda

2010

Polym J

339

273

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This article reviews the development of catalysts for ring-opening metathesis polymerization (ROMP), synthesis of polymers bearing amino acids and peptides by ROMP of functionalized norbornenes, formation of aggregates and micelles, and applications of the polymers to medical materials. It also describes the control of monomer unit sequences, that is, living polymerization to synthesize block copolymers, and alternating copolymerization that is achieved on the basis of acid-base interactions. Polymer Journal (2010) 42, 905-915; doi:10.1038/pj.2010.94; published online 13 October 2010Keywords: alternating copolymerization; amino acid; block copolymerization; living polymerization; metathesis catalyst; peptide; ROMP INTRODUCTIONOlefin metathesis reactions are metal-mediated carbon-carbon (C-C) double bond exchange processes, 1,2 which were discovered in the mid 1950s. Chauvin proposed the commonly accepted mechanism for metathesis involving a metallacyclobutane, as illustrated in Scheme 1. 3 Initially, olefin metathesis was regarded as an odd reaction, but now it has undoubtedly established the position as one of the most important C-C bond formation reactions applicable to synthesis of a wide variety of useful products. In the early stages, transition metal chlorides were used as catalysts for the reaction, but the transition metal carbene complex catalysts designed by Schrock and Grubbs have remarkably advanced mechanistic analysis and control of catalytic activity by the choice of ligands. In 2005, Chauvin, Grubbs and Schrock were awarded the Nobel Prize in chemistry for development of the metathesis method in organic synthesis.Olefin metathesis polymerization is an application of metathesis reactions to polymer synthesis and includes ring-opening metathesis polymerization (ROMP) and acyclic diene metathesis (ADMET) polycondensation (Scheme 2). ADMET has been extensively developed by Wagener since 1987 4 for the synthesis of polyolefins having regularly spaced functional group branches and high thermal stability and crystallinity. 5,6 ADMET is also useful for synthesizing polymeric materials containing in-chain functionality. Although the general structures of the polymers obtained by ROMP and ADMET are illustratable in the same fashion as shown in Scheme 2, a completely different treatment is necessary from the viewpoint of polymerization kinetics. The former involves chain polymerization, whereas the latter is a step-growth polymerization process.

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Section: Intermolecular Chain Transfermentioning

confidence: 99%

Recent advances in ring-opening metathesis polymerization, and application to synthesis of functional materials

Sutthasupa

Shiotsuki

Sanda

2010

Polym J

339

273

View full text Add to dashboard Cite

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“…Gillom et al 1) performed kinetic studies on the polymerization of norbornene initiated by Ti-based complexes in toluene solution. Using the same solvent, a study was performed by Schrock et al 2) on W-based complexes as initiators. These authors mentioned zero-order kinetics with respect to monomer and accounted for this behavior in considerFull Paper: The solvent influence was studied on the polymerizability of norbornene, whereby a Mo-based Schrock complex was used as the initiator due to its ability to generate a persistent active center.…”

Section: Introductionmentioning

confidence: 99%

“…Recently, our team started a comprehensive study on the structural parameters controlling the reactivity in ROMP. In a previous paper 5) , we presented kinetic parameters for the "living" polymerization of norbornene (chosen as the reference monomer) initiated by Mo(NAr)(O-t-Bu) 2 (CHCMe 2 Ph) (with Ar = Ph (iPr)2 ) in tetrahydrofuran (THF). First order kinetics with respect to both the monomer and the initiator were established and the rate constant of polymerization was measured.…”

Section: Introductionmentioning

confidence: 99%

Polymerizability of cycloalkenes in a living ring-opening metathesis polymerization initiated by Schrock complexes, 1. Effect of the solvent on the polymerization kinetics

Cazalis

Héroguez

Fontanille³

2000

Macromol. Chem. Phys.

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“…5,[8][9][10][11][12][13][14] Because this initiator tolerates a variety of functional groups, the molecular engineering of polymers with novel structures and functionalities, including side chain liquid crystalline polymers (SCLCPs), should be possible. Related tungsten complexes 15 have also been shown to behave as initiators for certain living polymerization reactions, 16,17 although tungsten complexes do not appear to tolerate functionalities as well as molybdenum complexes. 5 SCLCPs have been prepared mainly by radical polymerization of mesogenic acrylates and methacrylates, and by hydrosilating mesogenic olefins with Si-H groups in polysiloxane backbones.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Side Chain Liquid Crystal Polymers by Living Ring Opening Metathesis Polymerization. 1. Influence of Molecular Weight, Polydispersity, and Flexible Spacer Length (n=2-8) on the Thermotropic behavior of the Resulting Polymers

Komiya¹,

Pugh²,

Schrock³

1992

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Awte'a;e I h,,ir Decr fe~orse. ABSTRACT IwI2001 ~Olds) The living ring opening metathesis polymerization of 5-carbo(n-[(4'-methoxy-4-biphenylyl)oxy]alkyl)bicyclo[2.2.1]hept-2-ene (1-n, n=2-8) by Mo(CH-t-Bu)(NAr) (0-t-Bu) 2 (Ar=2,6-C 6 H 3 -t-Pr 2 ) is described. Polymers with degrees of polymerization from 5 to 100 and narrow molecular weight distributions (Mw/Mnz1.05-1.24) were obtained in high yield. All polymers exhibit an enantiotropic nematic mesophase. Glass transition and isotropization temperatures increase with increasing molecular weight and become independent at approximately 30-50 repeat units. The change in enthalpy of isotropization is relatively independent of molecular weight. Using polymer blends, it was shown that polydispersity has no effect on either the transition temperatures or the temperature range of isotropization. Isotropization alternates in an odd-even manner up to spacer lengths of n=6, and then levels off. Reproduction in whole or in part is permitted for any purpose of the United States Government.This document has been approved for public release and sale; its distribution is unlimited. (Ar = 2,6-C 6 H3-i-Pr2) is described. Polymers with degrees of polymerization from 5 to 100 and narrow molecular weight distributions (Mw/Mn = 1.05-1.24) were obtained in high yield. All polymers exhibit an enantiotropic nematic mesophase. Glass transition and isotropization temperatures increase with increasing molecular weight and become independent at approximately 30-50 repeat units. The change in enthalpy of isotropization is relatively independent of molecular weight. Using polymer blends, it was shown that polydispersity has no effect on either the transition temperatures or the temperature range of isotropization. Isotropization alternates in an odd-even manner up to spacer lengths of n = 6, and then levels off.

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Ring-opening polymerization of norbornene by a living tungsten alkylidene complex

Cited by 248 publications

References 3 publications

Recent advances in ring-opening metathesis polymerization, and application to synthesis of functional materials

Recent advances in ring-opening metathesis polymerization, and application to synthesis of functional materials

Polymerizability of cycloalkenes in a living ring-opening metathesis polymerization initiated by Schrock complexes, 1. Effect of the solvent on the polymerization kinetics

Synthesis of Side Chain Liquid Crystal Polymers by Living Ring Opening Metathesis Polymerization. 1. Influence of Molecular Weight, Polydispersity, and Flexible Spacer Length (n=2-8) on the Thermotropic behavior of the Resulting Polymers

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