A chiral thiourea and a phosphazene for fast and stereoselective organocatalytic ring-opening-polymerization of racemic lactide
نویسندگان
چکیده
The isoselective organocatalyzed ring-opening polymerization of rac-lactide is triggered by a chiral binary organocatalytic system, achieving highly semi-crystalline and metal-free polylactides.
منابع مشابه
Chiral indium alkoxide complexes as initiators for the stereoselective ring-opening polymerization of rac-lactide.
The indium complex InL(2)N'' has been prepared from the reaction of 2 equiv of ((t)Bu)(2)P(O)CH(2)CH((t)Bu)OH (HL) with InN''(3) (N'' = N(SiMe(3))(2)). This complex reacts with a further equivalent of 2,6-di-tert-butylphenol or HL to afford the adducts InL(2)(OAr) and InL(3), respectively. Confirmation that the anion L(-) exhibits "ligand self-recognition" in the formation of predominantly homo...
متن کاملOrganocatalytic 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...
متن کاملStereoselective ring-opening polymerization of racemic lactide using aluminum-achiral ligand complexes: exploration of a chain-end control mechanism.
Stereoselective polymerization of racemic lactide (rac-LA) was examined using Al-achiral ligand complexes. By introduction of substituents in aromatic rings of Schiff base ligands, a higher selectivity was obtained without any chiral auxiliaries in the catalyst via a chain-end control mechanism. The T(m) values (T(m) 170-192 degrees C) were comparable to or higher than that of homochiral polyme...
متن کاملRobust chiral zirconium alkoxide initiators for the room-temperature stereoselective ring-opening polymerisation of rac-lactide.
Chiral Schiff bases (1H to 4H) and a series of their Group 4 metal alkoxide complexes [(R-1)2Ti(O(i)Pr)2, (R-2)2Ti(O(i)Pr)2, (R-1)(2)Zr(O(i)Pr)2, (R-2)2Zr(O(i)Pr)2, (R-3)2Zr(O(i)Pr)2, (R-4)2Zr(O(i)Pr)2, (S-1)2Zr(O(i)Pr)2 and (rac-1)2Zr(O(i)Pr)2] have been prepared and characterised by 1H, and 13C NMR spectroscopy. In solution, both Lambda and Delta isomers were observed, suggesting a low degree...
متن کاملA robust zirconium N-heterocyclic carbene complex for the living and highly stereoselective ring-opening polymerization of rac-lactide.
A readily accessible and robust Zr-NHC complex was found to polymerize rac-lactide in a highly controlled, living and stereoselective manner to afford heterotactic PLA.
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ژورنال
عنوان ژورنال: Chemical Communications
سال: 2021
ISSN: ['1359-7345', '1364-548X']
DOI: https://doi.org/10.1039/d0cc08022e