Living ROMP of <i>exo</i>-Norbornene Esters Possessing Pd<sup>II</sup> SCS Pincer Complexes or Diaminopyridines

Pollino, Joel M.; Stubbs, Ludger P.; Weck, Marcus

doi:10.1021/ma025873n

Cited by 134 publications

(151 citation statements)

References 34 publications

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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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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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“…Taking the values of activation parameters, it is assumed that there may exist active ruthenium in chelated form, which is proved in the following studies [28,36,45].…”

Section: Resultsmentioning

confidence: 99%

Ring Opening Metathesis Polymerization

Lyapkov¹,

Kiselev²,

Bozhenkova³

et al. 2018

Recent Research in Polymerization

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In recent years, the olefins metathesis has established itself as a powerful tool for carboncarbon bonds forming and has found numerous applications in polymer chemistry. One of the important directions of metathesis is the polymerization with cycle opening. A study of new ruthenium catalysts, resistant to the many functional groups effects, has showed the possibility of synthesizing functionalized polymers with unique properties. In this chapter, reactivity and activation parameters of eight different norbornene dicarboxylic acid alkyl esters in the presence of a Hoveyda-Grubbs II catalyst for the ring opening metathesis polymerization were determined by 1 H NMR analysis in-situ. The molecules of esters differ in the aliphatic radical structure and the location of the substituent groups. Kinetic studies have shown that effective polymerization constants and activation parameters strongly depend on the monomer structure. It is shown that the elongation of the aliphatic radical does not significantly affect the reactivity, but significantly changes the activation parameters. The branching of the aliphatic radical significantly affects both the reactivity of the corresponding ester and the activation parameters of the polymerization. The position of the substituents in the norbornene ring of the ester also has a significant effect on the activation parameters of metathesis polymerization.

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“…The simplest conceptual route to metal-containing polymers is the direct polymerization of metal-containing monomers. For the specific preparation of block copolymers, several notable routes of this sort have been developed, including the ring-opening polymerization of ferrocene derivatives, 47 the ring-opening metathesis polymerization of metal-coordinated norbornenes and Pd-pincer complexes, 48,49 and the chain polymerization of vinylferrocene. 6 In each case, a metal-containing monomer that is stable to the polymerization conditions is necessary; thus, either particularly stable monomers or mild polymerization conditions are required.…”

Section: Spatial Organization With Block Copolymersmentioning

confidence: 99%

Hybrid metal–polymer composites from functional block copolymers

Grubbs

2005

J. Polym. Sci. A Polym. Chem.

142

102

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ABSTRACT:The combination of metals and polymers in hybrid materials is a research area of great current interest. A number of methods for controlling the positioning of metallic species within polymer matrices on the nanometer scale have been developed. This highlight focuses on the use of functional block copolymers for the localization of metal species, especially nanoparticles, on the nanometer scale through block copolymer phase segregation. Research from the author's group on the use of alkyne-functional block copolymers for the preparation of cobalt-containing materials is discussed in this context.

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Living ROMP of exo-Norbornene Esters Possessing Pd^II SCS Pincer Complexes or Diaminopyridines

Cited by 134 publications

References 34 publications

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

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

Ring Opening Metathesis Polymerization

Hybrid metal–polymer composites from functional block copolymers

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Living ROMP of exo-Norbornene Esters Possessing PdII SCS Pincer Complexes or Diaminopyridines

Cited by 134 publications

References 34 publications

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

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

Ring Opening Metathesis Polymerization

Hybrid metal–polymer composites from functional block copolymers

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Product

Resources

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Living ROMP of exo-Norbornene Esters Possessing Pd^II SCS Pincer Complexes or Diaminopyridines