Yttrium phosphasalen initiators for rac-lactide polymerization: excellent rates and high iso-selectivities.
J Am Chem Soc
; 134(51): 20577-80, 2012 Dec 26.
Article
em En
| MEDLINE
| ID: mdl-23231748
ABSTRACT
Highly active yttrium phosphasalen initiators for the stereocontrolled ring-opening polymerization of rac-lactide are reported. The initiators are coordinated by a new class of ancillary ligand an iminophosphorane derivative of the popular "salen" ligand, termed "phosphasalen". Changing the phosphasalen structure enables access to high iso-selectivities (P(i) = 0.84) or hetero-selectivities (P(s) = 0.87). The initiators also show very high rates, excellent polymerization control, and tolerance to low loadings; furthermore, no chiral auxiliaries/ligands are needed for the stereocontrol. The combination of such high rates with high iso-selectivities is very unusual.
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Bases de dados:
MEDLINE
Assunto principal:
Poliésteres
/
Ítrio
/
Dioxanos
/
Etilenodiaminas
/
Polimerização
Idioma:
En
Revista:
J Am Chem Soc
Ano de publicação:
2012
Tipo de documento:
Article
País de afiliação:
Reino Unido