Cited by 109biodegradable polymer synthesis and propertiesCarbon dioxide utilization in catalysisAdvanced Polymer Synthesis and Characterization

Bis- and Tris-Urea H-Bond Donors for Ring-Opening Polymerization: Unprecedented Activity and Control from an Organocatalyst

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Fastnacht, Kurt V., Spink, Samuel S., Dharmaratne, Nayanthara U., Pothupitiya, Jinal U., Datta, Partha P., Kiesewetter, Elizabeth T., Kiesewetter, Matthew K.·2016·ACS Macro Letters

Abstract

A new class of H-bond donating ureas was developed for the ring-opening polymerization (ROP) of lactone monomers, and they exhibit dramatic rate acceleration versus previous H-bond mediated polymerization catalysts. The most active of these new catalysts, a tris-urea H-bond donor, is among the most active organocatalysts known for ROP, yet it retains the high selectivity of H-bond mediated organocatalysts. The urea cocatalyst, along with an H-bond accepting base, exhibits the characteristics of a "living" ROP, is highly active, in one case, accelerating a reaction from days to minutes, and remains active at low catalyst loadings. The rate acceleration exhibited by this H-bond donor occurs for all base cocatalysts examined. A mechanism of action is proposed, and the new catalysts are shown to accelerate small molecule transesterifications versus currently known monothiourea catalysts. It is no longer necessary to choose between a highly active or highly selective organocatalyst for ROP.

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Crossref · 10.1021/acsmacrolett.6b00527

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  • The rate acceleration is proposed to arise from an "activated (thio)urea" mechanism in which each additional (thio)urea moiety enhances the acidity via intramolecular H-bond activation, supported by DFT calculations.

    “The rate acceleration is proposed to arise from an “activated (thio)urea” mechanism in which each additional (thio)urea moiety enhances the acidity via intramolecular H-bond activation (Scheme 13), supported by DFT calculations.”

    From Catalysis as an Enabling Science for Sustainable Polymers (2018) · cites this paper as [338]

  • Kiesewetter reported a series of bis- and tris-(thio)urea based H-bond donors, which exhibited dramatic rate acceleration compared to the mono-TU/amine systems, yet retaining the high selectivity for propagation over transesterification.

    “Kiesewetter reported a series of bis-and tris-(thio)urea based H-bond donors (Scheme 13), which exhibited dramatic rate acceleration compared to the mono-TU/amine systems, yet retaining the high selectivity for propagation over transesterification. 337,338”

    From Catalysis as an Enabling Science for Sustainable Polymers (2018) · cites this paper as [338]

  • The most active one, a trisurea/MTBD, is approximately 100 times faster than mono-TU/MTBD for the ROP of CL, with equally good control on molecular weights and molecular weight distributions (Ð < 1.05).

    “The most active one, a trisurea/MTBD, is approximately 100 times faster than mono-TU/MTBD for the ROP of CL, with equally good control on molecular weights and molecular weight distributions (Ð < 1.05).”

    From Catalysis as an Enabling Science for Sustainable Polymers (2018) · cites this paper as [338]

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Authors
Fastnacht, K. V., Spink, S. S., Dharmaratne, N. U., Pothupitiya, J. U., Datta, P. P., Kiesewetter, E. T., & Kiesewetter, M. K.
Affiliations
University of Rhode Island (US)
Corresponding author
Kiesewetter, Matthew K.
Venue
ACS Macro Letters
Published
2016-08-03
Volume
5
Issue
8
Pages
982-986
ISSN
2161-1653 (ISSN-L)
OpenAlex
W2500824099
Cited by
109
References
38
Citations by year
2026: 5 · 2025: 11 · 2024: 12 · 2023: 9 · 2022: 5 · 2021: 9 · 2020: 11 · 2019: 15 · 2018: 18 · 2017: 12 · 2016: 2
FWCI
6.41
Type
journal article
Language
en
Open access
Licence
cc-by-nc-nd
Locations
  • ACS Macro Letters (publishedVersion)
  • PubMed (publishedVersion)
  • Journal of Media Literacy Education (submittedVersion, cc-by-nc-nd)
  • Journal of Media Literacy Education (submittedVersion, cc-by)
Funders
Division of Chemistry (CHE-1554830)
Topics
  • Physical Sciences › Materials Science › Biomaterials › biodegradable polymer synthesis and properties
  • Physical Sciences › Chemical Engineering › Process Chemistry and Technology › Carbon dioxide utilization in catalysis
  • Physical Sciences › Chemistry › Organic Chemistry › Advanced Polymer Synthesis and Characterization
Keywords
ring-opening polymerization, lactone monomers, organocatalysis, living polymerization, transesterification, catalytic mechanism, catalyst selectivity

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