Cited by 76biodegradable polymer synthesis and propertiesAdvanced Polymer Synthesis and CharacterizationOrganometallic Complex Synthesis and Catalysis

Iron Tris(dibenzoylmethane)-Centered Polylactide Stars: Multiple Roles for the Metal Complex in Lactide Ring-Opening Polymerization

Gorczynski, Jessica L., Chen, Jianbin, Fraser, Cassandra L.·2005·Journal of the American Chemical Society

Abstract

Poly(lactic acid) (PLA)-supported dibenzoylmethane (dbm) and corresponding metal complexes have potential applications as biomaterials and catalysts. Using hydroxyl-functionalized dbm (i.e., dbmOH) as the initiator and Sn(oct)2 as the catalyst, lactide ring-opening polymerizations were unexpectedly slow (6 h), and PDIs broadened when molecular weights >10 000 were targeted. Because interactions between the dbm ligand and Sn(oct)2 may be responsible for the diminished catalyst activity and molecular weight control, iron(III) was employed as a protecting group to form Fe(dbmOH)3. Shorter reaction times (10 min) were noted with this trifunctional metalloinitiator and Sn(oct)2, and higher molecular weights were achievable. Moreover, it was discovered that Fe(dbmOH)3 serves not only as an initiator but also as a catalyst and activating group for the polymerization. Even without the tin catalyst, iron-centered polymers with low PDIs (<1.1) were obtained within 10 min ( approximately 70% monomer conversion). The resulting Fe(dbmPLA)3 stars were demetalated by acid treatment to generate dbmPLA for subsequent coordination to other metals. To explore the scope of iron beta-diketonate complexes as catalysts, additional studies were performed with dbmOH and benzyl alcohol initiators using either iron tris(dbm) or iron tris(acac) (acac = acetylacetonate) as the catalyst. Here too, PLA products were obtained, and the iron catalysts were readily separated by treatment with aqueous HCl.

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Crossref · 10.1021/ja0530927

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Authors
Gorczynski, J. L., Chen, J., & Fraser, C. L.
Affiliations
University of Virginia (US)
Venue
Journal of the American Chemical Society
Published
2005-10-06
Volume
127
Issue
43
Pages
14956-14957
ISSN
  • 0002-7863 (ISSN-L)
  • 1520-5126
OpenAlex
W2068861709
Cited by
76
References
8
Citations by year
2026: 1 · 2025: 1 · 2024: 1 · 2023: 5 · 2022: 4 · 2021: 5 · 2020: 1 · 2019: 3 · 2018: 5 · 2017: 5 · 2016: 6 · 2015: 3 · 2014: 3 · 2013: 5 · 2012: 4
FWCI
1.53
Type
journal article
Language
en
Open access
closed
Locations
  • Journal of the American Chemical Society (publishedVersion)
  • PubMed (publishedVersion)
Funders
Division of Chemistry
Topics
  • Physical Sciences › Materials Science › Biomaterials › biodegradable polymer synthesis and properties
  • Physical Sciences › Chemistry › Organic Chemistry › Advanced Polymer Synthesis and Characterization
  • Physical Sciences › Chemistry › Organic Chemistry › Organometallic Complex Synthesis and Catalysis
Keywords
polylactic acid, lactide ring-opening polymerization, dibenzoylmethane, star polymers, tin catalysts, molecular weight control, polydispersity index, demetallation, benzyl alcohol initiator, coordination polymers

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