Nontraditional Step‐Growth Polymerization: ADMET

Church, Allen C.; Smith, Jason A.; Pawlow, James H.; Wagener, Kenneth B.

doi:10.1002/0471220523.ch8

Cited by 6 publications

(7 citation statements)

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“…ADMET polymerization of M6 and M8 were performed using either 1.0 mol % Grubbs I or Grubbs II catalyst in CH 2 Cl 2 at 40 °C under continuous nitrogen purge (a technique applied to remove the generated ethylene) . The corresponding polymeric products were designated as P6-1 , P6-2 , P8-1 , and P8-2 , respectively.…”

Section: Resultsmentioning

confidence: 99%

“…Acyclic diene metathesis polymerization (ADMET) has been proved to be a powerful and convenient method for synthesizing polyolefins via step-growth mechanism . The polymerization can tolerate polar groups using ruthenium-based catalysts (best known as Grubbs catalysts); therefore, many functionalized polyethylenes with well-defined microstructures and advanced functions have been synthesized through rational design of diene monomers. − Among them, copolymers of ethylene with other vinyl monomers represent a series of precision polyethylenes with functional groups separated by aliphatic carbon chains of defined length. ,,− However, in most cases, only a single functional entity is introduced into the middle of the diene monomer structure, while more complex sequence has rarely been reported. We hypothesized that ADMET of diene monomers containing rigid cyclic structure would yield new types of periodic copolymer with good thermal stability and high crystallinity.…”

Section: Introductionmentioning

confidence: 99%

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Periodic Vinyl Copolymers Containing γ-Butyrolactone via ADMET Polymerization of Designed Diene Monomers with Built-in Sequence

Li¹,

Li²,

Deng³

et al. 2012

Macromolecules

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The synthesis of a new family of periodic copolymers containing γ-butyrolactones by acyclic diene metathesis polymerization (ADMET) and their thermal properties are presented. Two symmetric diene monomers, M6 and M8, were designed. Both monomers contain two γ-butyrolactone units, but they are different in the length of methylene spacers between cyclic structures and terminal alkenes. The monomers have been prepared by a two-step approach; first, the atom transfer radical addition (ATRA) of diethyl meso-2,5-diiodohexanedioate with either 1,5-hexadiene or 1,7-octadiene was conducted to yield intermediates containing two γ-iodo ester sequences; subsequently, the specific sequence was transformed into γ-butyrolactone unit via intramolecular cyclization upon heating. The two monomers were polymerized using two Grubbs catalysts (Grubbs I and Grubbs II) to produce four polymers with moderate to high molecular weights (P6-1, P6-2, P8-1, and P8-2) and hydrogenation of which gave the final saturated polymers. The expected periodic copolymers have been obtained and were characterized with a variety of methods, indicating that the γ-butyrolactone units could endure the polymerization and hydrogenation. Polymers catalyzed by Grubbs II catalyst suffer from chain heterogeneity due to severe olefin isomerization. Thermal properties of the polymers were investigated via thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). TGA measurements show that these polymers are stable up to 350 °C. DSC results demonstrate that the glass transition and melting behaviors of the polymers are not only affected by the rigidity of γ-butyrolactone units in polyethylene chains but also dependent on the methylene spacer length and chain homogeneity. Copolymerization of M6 or M8 with 1,9-decadiene resulted in random copolymers with lower γ-butyrolactone content and less regular chain structure. These copolymers exhibit lower T g or T m compared with the periodic copolymers.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Periodic Vinyl Copolymers Containing γ-Butyrolactone via ADMET Polymerization of Designed Diene Monomers with Built-in Sequence

Li¹,

Li²,

Deng³

et al. 2012

Macromolecules

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“…ADMET polymerization of 1 using Schrock’s catalyst afforded an oligomer (Figure ) with M n = 2300, which is approximately 3 repeat units ( n ∼ 3) . ADMET polymerization is ideally performed in bulk monomer to maximize monomer concentration and favor formation of polymer. , However, the monomer in this case is a solid well above room temperatures and above the temperature range of catalyst stability. The polymerization was carried out therefore in a concentrated solution of toluene.…”

Section: Discussionmentioning

confidence: 99%

“…A modified synthetic strategy from Wagener was used for the polymerization reactions. ,, A 25 mL Schlenk flask was charged with [(η 5 -C 5 H 4 (CH 2 ) 8 CHCH 2 )Mo(CO) 3 ] 2 (0.40 g, 0.51 mmol) and then treated with a solution of Schrock’s catalyst (5 mol %) in toluene (2 mL) while stirring to form a slurry. The flask was attached to a vacuum line (2 Torr) and opened to vacuum at periodic intervals (generally every 5−10 min) to remove ethylene gas.…”

Section: Methodsmentioning

confidence: 99%

Preparation of Photoreactive Oligomers by ADMET Polymerization of [(C₅H₄(CH₂)₈CH═CH₂)Mo(CO)₃]₂

2009

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Polymerization of the [(η5-C5H4(CH2)8CHCH2)Mo(CO)3]2 complex by acyclic diene metathesis polymerization (ADMET) is reported. The polymerization reactions were performed using Schrock’s catalyst, which resulted in formation of a polydisperse oligomer (M n = 2300 and M w/M n = 4.3) with Mo−Mo bonds in the oligomer chain. Under dilute solvent conditions, the reaction was shown to favor the formation of the ring-closing metathesis (RCM) product. The ADMET oligomer was photochemically degradable, and irradiation with λ > 520 nm light in CCl4 resulted in cleavage of the oligomer backbone and formation of the metal chloride complex [μ-C5H4(CH2)8CHCH(CH2)8C5H4{Mo(CO)3Cl}2]. The RCM product was also irradiated and the photochemical product is identical to that formed by irradiation of the oligomer. Copolymerization of [(η5-C5H4(CH2)8CHCH2)Mo(CO)3]2 with 1,9-decadiene using Grubbs’ second-generation catalyst resulted in a higher molecular weight oligomer (M n = 3400, M w/M n = 3.9).

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“…Synthetic methods for obtaining well-defined transition-metal-containing polymers are sought due to the useful properties of these materials. , Acyclic diene metathesis polymerization (ADMET) is a potentially attractive method for synthesizing polymers with transition metal complexes in the backbone because the catalysts employed are tolerant of many functional groups, the reactions conditions are mild, and because a wide range of architectures are accessible. – …”

Section: Introductionmentioning

confidence: 99%

Transition-Metal-Containing Polymers by ADMET: Polymerization of cis-Mo(CO)₄(Ph₂P(CH₂)₃CH═CH₂)₂

2008

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Polymerization of the cis-Mo(CO)4(Ph2P(CH2)3CHCH2)2 complex using acyclic diene metathesis (ADMET) polymerization is reported. Ideally, ADMET polymerization is performed in bulk monomer to maximize monomer concentration and favor formation of polymer. The monomer in this case is a solid with a melting temperature of 128 °C, which is well above room temperature and above the range of catalyst stability. The polymerization was carried out therefore in a concentrated solution of toluene. The complex underwent polymerization when catalyzed with Grubbs’ second-generation catalyst; neither Grubbs’ first-generation catalyst nor Schrock’s catalyst was active. Homopolymerization resulted in oligomers of M n = 2060 (n ≈ 3, GPC relative to polystyrene). At elevated temperatures the coordination core of the polymerized cis-Mo(CO)4(Ph2P(CH2)3CHCH2)2 complex isomerized to the trans geometry. Copolymerization with 1,9-decadiene was also carried out and resulted in an oligomer of slightly higher molecular weight, M n = 5800. It is suggested that ADMET is not an effective method for obtaining high molecular weight polymers in this case because the monomer is neither a liquid nor a low-melting solid, and therefore a high monomer concentration could not be achieved.

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Nontraditional Step‐Growth Polymerization: ADMET

Cited by 6 publications

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Periodic Vinyl Copolymers Containing γ-Butyrolactone via ADMET Polymerization of Designed Diene Monomers with Built-in Sequence

Periodic Vinyl Copolymers Containing γ-Butyrolactone via ADMET Polymerization of Designed Diene Monomers with Built-in Sequence

Preparation of Photoreactive Oligomers by ADMET Polymerization of [(C₅H₄(CH₂)₈CH═CH₂)Mo(CO)₃]₂

Transition-Metal-Containing Polymers by ADMET: Polymerization of cis-Mo(CO)₄(Ph₂P(CH₂)₃CH═CH₂)₂

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Nontraditional Step‐Growth Polymerization: ADMET

Cited by 6 publications

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Periodic Vinyl Copolymers Containing γ-Butyrolactone via ADMET Polymerization of Designed Diene Monomers with Built-in Sequence

Periodic Vinyl Copolymers Containing γ-Butyrolactone via ADMET Polymerization of Designed Diene Monomers with Built-in Sequence

Preparation of Photoreactive Oligomers by ADMET Polymerization of [(C5H4(CH2)8CH═CH2)Mo(CO)3]2

Transition-Metal-Containing Polymers by ADMET: Polymerization of cis-Mo(CO)4(Ph2P(CH2)3CH═CH2)2

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Preparation of Photoreactive Oligomers by ADMET Polymerization of [(C₅H₄(CH₂)₈CH═CH₂)Mo(CO)₃]₂

Transition-Metal-Containing Polymers by ADMET: Polymerization of cis-Mo(CO)₄(Ph₂P(CH₂)₃CH═CH₂)₂