Cocatalyst Binding Effects in Organocatalytic Ring-Opening Polymerization of l-Lactide
نویسندگان
چکیده
منابع مشابه
Organocatalytic ring-opening polymerization.
Modern synthetic methods have revolutionized polymer chemistry through the development of new and powerful strategies for the controlled synthesis of complex polymer architectures.1-5 Many of these developments were spawned by new classes of transition metal catalysts for the synthesis of new polyolefin microstructures,5 the design of highly efficient families of “living” polymerization strateg...
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Thiourea (TU)/amine base cocatalysts are commonly employed for well-controlled, highly active "living" organocatalytic ring-opening polymerizations (ROPs) of cyclic esters and carbonates. In this work, several of the most active cocatalyst pairs are shown by 1H NMR binding studies to be highly associated in solution, dominating all other known noncovalent catalyst/reagent interactions during RO...
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For the first time, the controlled ring-opening polymerization (ROP) of ε-thionocaprolactone (tnCL) is conducted. The organocatalytic ROP of tnCL occurs without carbonyl scrambling, leading to homopoly(ε-thionocaprolactone) (PtnCL). The ROP by base catalysts alone is proposed to proceed via a nucleophilic mechanism, while the addition of an H-bond donating thiourea (TU) is shown to provide exce...
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A family of chiral zinc amido-oxazolinate complexes are shown to be highly active and isoselective initiators for the ring-opening polymerization (ROP) of rac-lactide, yielding isotactic stereoblock polylactides (PLA) with Pm up to 0.91. This represents the highest isoselectivity observed with zinc-based catalysts for ROP of rac-lactide.
متن کاملMagnesium Pyrazolyl-Indolyl Complexes as Catalysts for Ring-Opening Polymerization of L-Lactide
A series indole-based ligand precursors, PzRIndH (R = H, PzHIndH; R = Me, PzMeIndH; R = t-Bu, PztBuIndH; and R = Ph, PzPhIndH), have been synthesized via copper-catalyzed N-arylation (for PzHIndH) or the Bartoli indole synthesis (for PzMeIndH, PztBuIndH and PzPhIndH) reactions with moderate to high yield. Reactions of these ligand precursors with 0.7 equivalent of MgBu2 in THF (for 1) or hexane...
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ژورنال
عنوان ژورنال: Macromolecules
سال: 2015
ISSN: 0024-9297,1520-5835
DOI: 10.1021/acs.macromol.5b01140