Investigation of Organoboronates in Metathesis Polymerization

Wolfe, Patrick S.; Wagener, Kenneth B.

doi:10.1021/ma981784s

Cited by 42 publications

(22 citation statements)

References 24 publications

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“…Signals due to traces of hexane used during isolation of the polymer are also observed at d ¼ 0.9 and 1.0 ppm, even though each sample was dried in vacuo for 24 h prior to analysis. Similar hydrocarbon incorporation by polymers derived from aminoacids was previously reported by Gibson et al [16] It is known that an endo isomer is much less reactive than the corresponding exo isomer towards ROMP [1, [27][28][29][30][31][32][33][34] and herein, NBAz substrate follows the same trend. The difference in reactivity has been attributed to the catalyst inhibition by chelation of the propagating metal center by the endo functional group.…”

Section: Romp Reactivity Of Endo-and Exo-nbazsupporting

confidence: 83%

“…[1,[27][28][29][30][31][32][33][34] So, we investigated ROMP of both racemic endo-NBAz and exo-NBAz using Ru-initiators as (PCy 3 ) 2 (Cl) 2-Ru CHPh, 1, and (SIMes)(PCy 3 )(Cl) 2 Ru CHPh, 2, in order to evaluate the tolerance of these catalysts towards the azlactone ring and to compare the polymerizability of the two isomers.…”

Section: Romp Of Nbaz By Ruthenium Initiatorsmentioning

confidence: 99%

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Synthesis and Ring‐Opening Metathesis Polymerization (ROMP) Reactivity of endo‐and exo‐Norbornenylazlactone Using Ruthenium Catalysts

Lapinte

Brosse

Fontaine

2004

Macro Chemistry & Physics

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Summary: Norbornenylazlactone (NBAz) was prepared by a Diels‐Alder cycloaddition between cyclopentadiene and 2‐vinyl‐4,4‐dimethyl‐5‐oxazolone. The stereoselectivity of this pericyclic reaction was in favour of endo isomers. The ring‐opening metathesis polymerization (ROMP) of NBAz was carried out in presence of ruthenium catalysts [(PCy3)2(Cl)2RuCHPh 1; (SIMes)(PCy3)(Cl)2RuCHPh 2 (SIMes: 1,3‐dimesityl‐4,5‐dihydroimidazol‐2‐ylidene); (PiPr3)2(Cl)2RuCHSPh 3; (PiPr3)(Cl)2RuCH(CH2)2C, N‐2‐C5H4N 4]. It was found that the exo isomer is much more reactive than the corresponding endo isomer. Some hypotheses of mechanism are suggested to justify the low polymerization rate of endo isomer using the results of NBAz derivatives as the hydrolyzed NBAz, 5, and the coupling product between NBAz and glycine methyl ester hydrochloride, 6. For exo‐NBAz, the propagating rate constant, kp, was determined with the four Ru‐initiators and their activity decreases in the order 2 > 1 > 3 > 4. Complementary kinetic measurements with 1 and 2 were given as kp/ki ratio. The ROMP of exo isomer was faster with 2 than 1 in spite of a worse control of the chains size. The azlactone ring survived intact during the polymerization and may be used for further reactions with nucleophiles.ROMP of NBAz by ruthenium initiators.magnified imageROMP of NBAz by ruthenium initiators.

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Section: Romp Reactivity Of Endo-and Exo-nbazsupporting

confidence: 83%

Section: Romp Of Nbaz By Ruthenium Initiatorsmentioning

confidence: 99%

Synthesis and Ring‐Opening Metathesis Polymerization (ROMP) Reactivity of endo‐and exo‐Norbornenylazlactone Using Ruthenium Catalysts

Lapinte

Brosse

Fontaine

2004

Macro Chemistry & Physics

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“…In agreement with this work, previous studies of the ROMP of norbornene derivatives have also observed that endo isomers polymerize more slowly than their exo counterparts. 54,[60][61][62][63] The observed rate trends could be motivated by a combination of factors, including but not limited to pyridine coordination, olefin coordination, cycloaddition, and formation of a sixmembered chelate involving the ruthenium center and the esteror imide-functionalized chain end. 64 In order to deconvolute these potential contributions to khomo, we examined the mechanism of ROMP.…”

Section: Chart 1 Monomer Design For Ring-opening Metathesis Copolymementioning

confidence: 99%

Design, Synthesis, and Self-Assembly of Polymers with Tailored Graft Distributions

et al. 2017

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Grafting density and graft distribution impact the chain dimensions and physical properties of polymers. However, achieving precise control over these structural parameters presents long-standing synthetic challenges. In this report, we introduce a versatile strategy to synthesize polymers with tailored architectures via grafting-through ring-opening metathesis polymerization (ROMP). One-pot copolymerization of an ω-norbornenyl macromonomer and a discrete norbornenyl co-monomer (diluent) provides opportunities to control the backbone sequence and therefore the side chain distribution. Toward sequence control, the homopolymerization kinetics of 23 diluents were studied, representing diverse variations in the stereochemistry, anchor groups, and substituents. These modifications tuned the homopolymerization rate constants over two orders of magnitude (0.36 M −1 s −1 < khomo < 82 M −1 s −1 ). Rate trends were identified and elucidated by complementary mechanistic and density functional theory (DFT) studies. Building on this foundation, complex architectures were achieved through copolymerizations of selected diluents with a poly(D,L-lactide) (PLA), polydimethylsiloxane (PDMS), or polystyrene (PS) macromonomer. The cross-propagation rate constants were obtained by non-linear least squares fitting of the instantaneous co-monomer concentrations according to the Mayo-Lewis terminal model. Indepth kinetic analyses indicate a wide range of accessible macromonomer/diluent reactivity ratios (0.08 < r1/r2 < 20), corresponding to blocky, gradient, or random backbone sequences. We further demonstrated the versatility of this copolymerization approach by synthesizing AB graft diblock polymers with tapered, uniform, and inverse-tapered molecular "shapes." Small-angle X-ray scattering analysis of the self-assembled structures illustrates effects of the graft distribution on the domain spacing and backbone conformation. Collectively, the insights provided herein into the ROMP mechanism, monomer design, and homo-and copolymerization rate trends offer a general strategy for the design and synthesis of graft polymers with arbitrary architectures. Controlled copolymerization therefore expands the parameter space for molecular and materials design.

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“…These results are similar with those previously reported about the lower reactivity of endo-stereoisomers of norbornene towards ROMP compared with exo-stereoisomers. [28][29][30][31][32][33][34][35] This difference of reactivity is also explained by the geometry of the monomer which hinders the double bond accessibility.…”

Section: Kinetic Studiesmentioning

confidence: 99%

Ring Opening Metathesis Polymerization (ROMP) of cis‐ and trans‐3,4‐Bis(acetyloxymethyl)cyclobut‐1‐enes and Synthesis of Block Copolymers

Lapinte¹,

Frémont²,

Montembault³

et al. 2004

Macro Chemistry & Physics

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Summary: The synthesis and living ring opening metathesis polymerization (ROMP) of diacetate functionalized cyclobutene derivatives cis‐3,4‐bis(acetyloxymethyl)cyclobutene (2) and trans‐3,4‐bis(acetyloxymethyl)cyclobutene (3) were investigated with the functional group tolerant initiators (PCy3)2(Cl)2RuCHPh (I) and (SIMes)(PCy3)(Cl)2RuCHPh (II) (SIMes: 1,3‐dimesityl‐4,5‐dihydroimidazol‐2‐ylidene). The kinetic parameters of the ROMP initiated by the ruthenium alkylidene complexes I and II were determined and correlated to monomer stereochemistry. The cis isomer 2 was found to be more reactive than the trans isomer 3 and to generate functional polymers of narrow molecular weight distribution especially with the classical “first generation Grubbs catalyst” I. Block copolymers containing 2 and cyclooctadiene (COD) or norbornene (NBE) were synthesized. Block copolymer poly(2‐b‐COD) was hydrolyzed and converted to a material with a block bearing hydrophilic alcohol functional groups and hydrophobic block.SEC elution profiles: poly(2) prepolymer and block copolymer poly(2‐b‐COD).magnified imageSEC elution profiles: poly(2) prepolymer and block copolymer poly(2‐b‐COD).

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Investigation of Organoboronates in Metathesis Polymerization

Cited by 42 publications

References 24 publications

Synthesis and Ring‐Opening Metathesis Polymerization (ROMP) Reactivity of endo‐and exo‐Norbornenylazlactone Using Ruthenium Catalysts

Synthesis and Ring‐Opening Metathesis Polymerization (ROMP) Reactivity of endo‐and exo‐Norbornenylazlactone Using Ruthenium Catalysts

Design, Synthesis, and Self-Assembly of Polymers with Tailored Graft Distributions

Ring Opening Metathesis Polymerization (ROMP) of cis‐ and trans‐3,4‐Bis(acetyloxymethyl)cyclobut‐1‐enes and Synthesis of Block Copolymers

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