Metal-Size Influence in Iso-Selective Lactide Polymerization

Autor:	Bakewell, C, White, AJP, Long, NJ, Williams, CK
Přispěvatelé:	Engineering & Physical Science Research Council (EPSRC)
Rok vydání:	2014
Předmět:	Science & Technology lanthanum ring-opening polymerization Chemistry Multidisciplinary Organic Chemistry STEREOCOMPLEX FORMATION General Medicine iso-selectivity RACEMIC LACTIDE STEREOSELECTIVE POLYMERIZATION 3. Good health lutetium Chemistry YTTRIUM PHOSPHASALEN INITIATORS BIS(PHENOLATO) LIGANDS RAC-LACTIDE Physical Sciences lactide CYCLIC ESTERS 03 Chemical Sciences ALUMINUM COMPLEXES INDIUM CATALYST
Zdroj:	Angewandte Chemie. 126:9380-9384
ISSN:	0044-8249
Popis:	Iso-selective initiators for the ring-opening polymerization (ROP) of rac-lactide are rare outside of Group 13. We describe the first examples of highly iso-selective lutetium initiators. The phosphasalen lutetium ethoxide complex shows excellent iso-selectivity, with a Pi value of 0.81–0.84 at 298 K, excellent rates, and high degrees of polymerization control. Conversely, the corresponding La derivative exhibits moderate heteroselectivity (Ps=0.74, 298 K). Thus, the choice of metal center is shown to be crucial in determining the level and mode of stereocontrol. The relative order of rates for the series of complexes is inversely related to metallic covalent radius: that is, La>Y>Lu.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_dedup___::1c9f6a6a97ba6d17b1f990073a8b8fe7 https://doi.org/10.1002/ange.201403643 Zobrazit plný text záznamu Plný text ve formátu PDF Plný text ve formátu HTML
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