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A Bicyclo[4.2.0]octene-Derived Monomer Provides Completely Linear Alternating Copolymers via Alternating Ring-Opening Metathesis Polymerization (AROMP).

Tan L, Parker KA, Sampson NS - Macromolecules (2014)

Bottom Line: Strained bicyclic carbomethoxy olefins were utilized as substrates in alternating ring-opening metathesis polymerization and found to provide low-dispersity polymers with novel backbones.Chem.Soc.2009, 131, 3444].

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Stony Brook University , Stony Brook, New York 11794-3400, United States.

ABSTRACT
Strained bicyclic carbomethoxy olefins were utilized as substrates in alternating ring-opening metathesis polymerization and found to provide low-dispersity polymers with novel backbones. The polymerization of methyl bicyclo[4.2.0]oct-7-ene-7-carboxylate with cyclohexene in the presence of the fast-initiating Grubbs catalyst (H2IMes)(3-Br-Pyr)2Cl2Ru=CHPh leads to a completely linear as well as alternating copolymer, as demonstrated by NMR spectroscopy, isotopic labeling, and gel permeation chromatography. In contrast, intramolecular chain-transfer reactions were observed with [5.2.0] and [3.2.0] bicyclic carbomethoxy olefins, although to a lesser extent than with the previously reported monocyclic cyclobutenecarboxylic ester monomers [Song A.; Parker K. A.; Sampson N. S.J. Am. Chem. Soc.2009, 131, 3444]. Inclusion of cyclohexyl rings fused to the copolymer backbone minimizes intramolecular chain-transfer reactions and provides a framework for creating alternating functionality in a one-step polymerization.

No MeSH data available.


Kineticmonitoring of ring-opening metathesis of monomers 1 and 3–5. Monomer and GrubbsIII catalyst were mixed in a 1:1 ratio, [A] = [GrubbsIII] = 0.03 M. Percent conversion was determined by 1HNMR spectroscopy and integration of the Ru alkylidene α protonresonance relative to the methyl ester resonances (Supporting Information). t1/2 wereobtained from the plot, monomer 1: t1/2 = 40 min, monomer 3: t1/2 = 25 min, monomer 4: t1/2 = 100 min; monomer 5: t1/2 = 300 min. Each experiment was performed at leasttwice, and data from representative experiments are shown.
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fig2: Kineticmonitoring of ring-opening metathesis of monomers 1 and 3–5. Monomer and GrubbsIII catalyst were mixed in a 1:1 ratio, [A] = [GrubbsIII] = 0.03 M. Percent conversion was determined by 1HNMR spectroscopy and integration of the Ru alkylidene α protonresonance relative to the methyl ester resonances (Supporting Information). t1/2 wereobtained from the plot, monomer 1: t1/2 = 40 min, monomer 3: t1/2 = 25 min, monomer 4: t1/2 = 100 min; monomer 5: t1/2 = 300 min. Each experiment was performed at leasttwice, and data from representative experiments are shown.

Mentions: First, we undertook kinetic monitoring of the initialring-openingmetathesis (ROM) reactions for each of these monomers by 1H NMR spectroscopy (Figure 2). In each ofthe experiments, an equimolar amount of monomer A (thebicycloalkene ester) and Grubbs III catalyst was mixed in CD2Cl2. The disappearance of the alkylidene signal of thecatalyst at 19.1 ppm was followed by 1H NMR spectroscopy;the signal was integrated relative to the methyl ester signals between3.8 and 3.5 ppm. Under the conditions of the experiment, 50% of monomer 3 was ring opened in 25 min, whereas 50% of monomer 1 was ring-opened in 40 min. Under the same conditions, monomer 4 underwent 50% ring-opening in 100 min and monomer 5 required 300 min for 50% ring-opening. Thus, upon additionof Grubbs III catalyst, monomer 3 has the fastest ring-openingrate, in accordance with the predicted ring strains.36−38


A Bicyclo[4.2.0]octene-Derived Monomer Provides Completely Linear Alternating Copolymers via Alternating Ring-Opening Metathesis Polymerization (AROMP).

Tan L, Parker KA, Sampson NS - Macromolecules (2014)

Kineticmonitoring of ring-opening metathesis of monomers 1 and 3–5. Monomer and GrubbsIII catalyst were mixed in a 1:1 ratio, [A] = [GrubbsIII] = 0.03 M. Percent conversion was determined by 1HNMR spectroscopy and integration of the Ru alkylidene α protonresonance relative to the methyl ester resonances (Supporting Information). t1/2 wereobtained from the plot, monomer 1: t1/2 = 40 min, monomer 3: t1/2 = 25 min, monomer 4: t1/2 = 100 min; monomer 5: t1/2 = 300 min. Each experiment was performed at leasttwice, and data from representative experiments are shown.
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fig2: Kineticmonitoring of ring-opening metathesis of monomers 1 and 3–5. Monomer and GrubbsIII catalyst were mixed in a 1:1 ratio, [A] = [GrubbsIII] = 0.03 M. Percent conversion was determined by 1HNMR spectroscopy and integration of the Ru alkylidene α protonresonance relative to the methyl ester resonances (Supporting Information). t1/2 wereobtained from the plot, monomer 1: t1/2 = 40 min, monomer 3: t1/2 = 25 min, monomer 4: t1/2 = 100 min; monomer 5: t1/2 = 300 min. Each experiment was performed at leasttwice, and data from representative experiments are shown.
Mentions: First, we undertook kinetic monitoring of the initialring-openingmetathesis (ROM) reactions for each of these monomers by 1H NMR spectroscopy (Figure 2). In each ofthe experiments, an equimolar amount of monomer A (thebicycloalkene ester) and Grubbs III catalyst was mixed in CD2Cl2. The disappearance of the alkylidene signal of thecatalyst at 19.1 ppm was followed by 1H NMR spectroscopy;the signal was integrated relative to the methyl ester signals between3.8 and 3.5 ppm. Under the conditions of the experiment, 50% of monomer 3 was ring opened in 25 min, whereas 50% of monomer 1 was ring-opened in 40 min. Under the same conditions, monomer 4 underwent 50% ring-opening in 100 min and monomer 5 required 300 min for 50% ring-opening. Thus, upon additionof Grubbs III catalyst, monomer 3 has the fastest ring-openingrate, in accordance with the predicted ring strains.36−38

Bottom Line: Strained bicyclic carbomethoxy olefins were utilized as substrates in alternating ring-opening metathesis polymerization and found to provide low-dispersity polymers with novel backbones.Chem.Soc.2009, 131, 3444].

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Stony Brook University , Stony Brook, New York 11794-3400, United States.

ABSTRACT
Strained bicyclic carbomethoxy olefins were utilized as substrates in alternating ring-opening metathesis polymerization and found to provide low-dispersity polymers with novel backbones. The polymerization of methyl bicyclo[4.2.0]oct-7-ene-7-carboxylate with cyclohexene in the presence of the fast-initiating Grubbs catalyst (H2IMes)(3-Br-Pyr)2Cl2Ru=CHPh leads to a completely linear as well as alternating copolymer, as demonstrated by NMR spectroscopy, isotopic labeling, and gel permeation chromatography. In contrast, intramolecular chain-transfer reactions were observed with [5.2.0] and [3.2.0] bicyclic carbomethoxy olefins, although to a lesser extent than with the previously reported monocyclic cyclobutenecarboxylic ester monomers [Song A.; Parker K. A.; Sampson N. S.J. Am. Chem. Soc.2009, 131, 3444]. Inclusion of cyclohexyl rings fused to the copolymer backbone minimizes intramolecular chain-transfer reactions and provides a framework for creating alternating functionality in a one-step polymerization.

No MeSH data available.