It is Better with Salt: Aqueous Ring-Opening Metathesis Polymerization at Neutral pH (2024)

Foster, J. C., Grocott, M. C., Arkinstall, L. A., Varlas, S., Redding, M. J., Grayson, S. M., & O'Reilly, R. K. (2020). It is Better with Salt: Aqueous Ring-Opening Metathesis Polymerization at Neutral pH. Journal of the American Chemical Society, 142(32), 13878-13885. https://doi.org/10.1021/jacs.0c05499

Foster, Jeffrey C. ; Grocott, Marcus C. ; Arkinstall, Lucy A. et al. / It is Better with Salt : Aqueous Ring-Opening Metathesis Polymerization at Neutral pH. In: Journal of the American Chemical Society. 2020 ; Vol. 142, No. 32. pp. 13878-13885.

@article{b3a13016f0734929827226b1b18ccd1a,

title = "It is Better with Salt: Aqueous Ring-Opening Metathesis Polymerization at Neutral pH",

abstract = "Aqueous ring-opening metathesis polymerization (ROMP) is a powerful tool for polymer synthesis under environmentally friendly conditions, functionalization of biomacromolecules, and preparation of polymeric nanoparticles via ROMP-induced self-assembly (ROMPISA). Although new water-soluble Ru-based metathesis catalysts have been developed and evaluated for their efficiency in mediating cross metathesis (CM) and ring-closing metathesis (RCM) reactions, little is known with regards to their catalytic activity and stability during aqueous ROMP. Here, we investigate the influence of solution pH, the presence of salt additives, and catalyst loading on ROMP monomer conversion and catalyst lifetime. We find that ROMP in aqueous media is particularly sensitive to chloride ion concentration and propose that this sensitivity originates from chloride ligand displacement by hydroxide or H2O at the Ru center, which reversibly generates an unstable and metathesis inactive complex. The formation of this Ru-(OH)n complex not only reduces monomer conversion and catalyst lifetime but also influences polymer microstructure. However, we find that the addition of chloride salts dramatically improves ROMP conversion and control. By carrying out aqueous ROMP in the presence of various chloride sources such as NaCl, KCl, or tetrabutylammonium chloride, we show that diblock copolymers can be readily synthesized via ROMPISA in solutions with high concentrations of neutral H2O (i.e., 90 v/v%) and relatively low concentrations of catalyst (i.e., 1 mol %). The capability to conduct aqueous ROMP at neutral pH is anticipated to enable new research avenues, particularly for applications in biological media, where the unique characteristics of ROMP provide distinct advantages over other polymerization strategies.",

author = "Foster, {Jeffrey C.} and Grocott, {Marcus C.} and Arkinstall, {Lucy A.} and Spyridon Varlas and Redding, {McKenna J.} and Grayson, {Scott M.} and O'Reilly, {Rachel K.}",

note = "Publisher Copyright: Copyright {\textcopyright} 2020 American Chemical Society.",

year = "2020",

month = aug,

day = "12",

doi = "10.1021/jacs.0c05499",

language = "English",

volume = "142",

pages = "13878--13885",

journal = "Journal of the American Chemical Society",

issn = "0002-7863",

publisher = "American Chemical Society",

number = "32",

}

Foster, JC, Grocott, MC, Arkinstall, LA, Varlas, S, Redding, MJ, Grayson, SM & O'Reilly, RK 2020, 'It is Better with Salt: Aqueous Ring-Opening Metathesis Polymerization at Neutral pH', Journal of the American Chemical Society, vol. 142, no. 32, pp. 13878-13885. https://doi.org/10.1021/jacs.0c05499

It is Better with Salt: Aqueous Ring-Opening Metathesis Polymerization at Neutral pH. / Foster, Jeffrey C.; Grocott, Marcus C.; Arkinstall, Lucy A. et al.
In: Journal of the American Chemical Society, Vol. 142, No. 32, 12.08.2020, p. 13878-13885.

Research output: Contribution to journal › Article › peer-review

TY - JOUR

T1 - It is Better with Salt

T2 - Aqueous Ring-Opening Metathesis Polymerization at Neutral pH

AU - Foster, Jeffrey C.

AU - Grocott, Marcus C.

AU - Arkinstall, Lucy A.

AU - Varlas, Spyridon

AU - Redding, McKenna J.

AU - Grayson, Scott M.

AU - O'Reilly, Rachel K.

N1 - Publisher Copyright:Copyright © 2020 American Chemical Society.

PY - 2020/8/12

Y1 - 2020/8/12

N2 - Aqueous ring-opening metathesis polymerization (ROMP) is a powerful tool for polymer synthesis under environmentally friendly conditions, functionalization of biomacromolecules, and preparation of polymeric nanoparticles via ROMP-induced self-assembly (ROMPISA). Although new water-soluble Ru-based metathesis catalysts have been developed and evaluated for their efficiency in mediating cross metathesis (CM) and ring-closing metathesis (RCM) reactions, little is known with regards to their catalytic activity and stability during aqueous ROMP. Here, we investigate the influence of solution pH, the presence of salt additives, and catalyst loading on ROMP monomer conversion and catalyst lifetime. We find that ROMP in aqueous media is particularly sensitive to chloride ion concentration and propose that this sensitivity originates from chloride ligand displacement by hydroxide or H2O at the Ru center, which reversibly generates an unstable and metathesis inactive complex. The formation of this Ru-(OH)n complex not only reduces monomer conversion and catalyst lifetime but also influences polymer microstructure. However, we find that the addition of chloride salts dramatically improves ROMP conversion and control. By carrying out aqueous ROMP in the presence of various chloride sources such as NaCl, KCl, or tetrabutylammonium chloride, we show that diblock copolymers can be readily synthesized via ROMPISA in solutions with high concentrations of neutral H2O (i.e., 90 v/v%) and relatively low concentrations of catalyst (i.e., 1 mol %). The capability to conduct aqueous ROMP at neutral pH is anticipated to enable new research avenues, particularly for applications in biological media, where the unique characteristics of ROMP provide distinct advantages over other polymerization strategies.

AB - Aqueous ring-opening metathesis polymerization (ROMP) is a powerful tool for polymer synthesis under environmentally friendly conditions, functionalization of biomacromolecules, and preparation of polymeric nanoparticles via ROMP-induced self-assembly (ROMPISA). Although new water-soluble Ru-based metathesis catalysts have been developed and evaluated for their efficiency in mediating cross metathesis (CM) and ring-closing metathesis (RCM) reactions, little is known with regards to their catalytic activity and stability during aqueous ROMP. Here, we investigate the influence of solution pH, the presence of salt additives, and catalyst loading on ROMP monomer conversion and catalyst lifetime. We find that ROMP in aqueous media is particularly sensitive to chloride ion concentration and propose that this sensitivity originates from chloride ligand displacement by hydroxide or H2O at the Ru center, which reversibly generates an unstable and metathesis inactive complex. The formation of this Ru-(OH)n complex not only reduces monomer conversion and catalyst lifetime but also influences polymer microstructure. However, we find that the addition of chloride salts dramatically improves ROMP conversion and control. By carrying out aqueous ROMP in the presence of various chloride sources such as NaCl, KCl, or tetrabutylammonium chloride, we show that diblock copolymers can be readily synthesized via ROMPISA in solutions with high concentrations of neutral H2O (i.e., 90 v/v%) and relatively low concentrations of catalyst (i.e., 1 mol %). The capability to conduct aqueous ROMP at neutral pH is anticipated to enable new research avenues, particularly for applications in biological media, where the unique characteristics of ROMP provide distinct advantages over other polymerization strategies.

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U2 - 10.1021/jacs.0c05499

DO - 10.1021/jacs.0c05499

M3 - Article

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AN - SCOPUS:85089609411

SN - 0002-7863

VL - 142

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EP - 13885

JO - Journal of the American Chemical Society

JF - Journal of the American Chemical Society

IS - 32

ER -

Foster JC, Grocott MC, Arkinstall LA, Varlas S, Redding MJ, Grayson SM et al. It is Better with Salt: Aqueous Ring-Opening Metathesis Polymerization at Neutral pH. Journal of the American Chemical Society. 2020 Aug 12;142(32):13878-13885. doi: 10.1021/jacs.0c05499