Organocatalytic Stereoselective Ring-Opening Polymerization of Lactide with Dimeric Phosphazene Bases

Journal Article · Mon Jan 01 00:00:00 EST 2007 · Journal of the American Chemical Society

DOI:https://doi.org/10.1021/ja074131c· OSTI ID:940792

Zhang, Lei ^[1]; Nederberg, Fredrik ^[1]; Messman, Jamie M ^[2]; Pratt, Russel C ^[1]; Hedrick, James ^[1]; Wade, Charles G ^[1]

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1. Almaden Research Center
2. ORNL

Highly isotactic polylactide with a high melting temperature was synthesized from rac-lactide through an organocatalytic route using dimeric phosphazene base 1-tert-butyl-2,2,4,4,4-pentakis(dimethylamino)-2 5,4 5-catenadi(phosphazene) (P2-t-Bu) catalyst at low temperature. Microstructural analysis of the prepared polymer using homodecoupled 1H NMR spectroscopy revealed the formation of a stereoblock architecture containing long isotactic sequence of R- and S- blocks in the main chain. A proposed mechanism involving chain-end control and stereoerror explains the stereoselective polymerization.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 940792
• Journal Information: Journal of the American Chemical Society, Vol. 129, Issue 42; ISSN 0002-7863
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CATALYSTS
POLYMERIZATION
LACTATES
ORGANIC PHOSPHORUS COMPOUNDS
ORGANIC POLYMERS
STEREOCHEMISTRY
MOLECULAR STRUCTURE