Isoselective ring-opening polymerization of rac-lactide initiated by achiral heteroscorpionate zwitterionic zinc complexes.
نویسندگان
چکیده
A highly isotactic stereoblock PLA has been obtained using the achiral heteroscorpionate zwitterionic zinc complexes as catalysts, for the first time, via a chain-end control mechanism.
منابع مشابه
Zinc-Catalyzed Highly Isoselective Ring Opening Polymerization of rac-Lactide
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.
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A series of racemic 2-[(2′-(dimethylamino)binaphthyl-2-ylimino)methyl]-4-R2-6-R(1)-phenols (L1H–L6H) were reacted with 1 equiv. of Mg[N(SiMe3)2]2 or Zn[N(SiMe3)2]2 to provide three heteroleptic magnesium silylamido complexes [(L4–(6))MgN(SiMe3)2] (4a: R(1) = R(2) = cumyl; 5a: R(1) = CPh3, R(2) = Me; 6a: R(1) = CPh3, R(2) = (t)Bu) and one heteroleptic zinc silylamido complex [(L(4))ZnN(SiMe3)2] ...
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عنوان ژورنال:
- Chemical communications
دوره 50 77 شماره
صفحات -
تاریخ انتشار 2014