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Your search keyword '"Chen, Hsuan-Ying"' showing total 9 results
Start Over Author "Chen, Hsuan-Ying" Journal organometallics
9 results on '"Chen, Hsuan-Ying"'

9. Comparative Study of LactidePolymerization with Lithium, Sodium, Magnesium, and Calcium Complexesof BHT.

Author

Chen, Hsuan-Ying, Mialon, Laurent, Abboud, Khalil A., and Miller, Stephen A.

Subjects
*LACTIDES, *POLYMERIZATION, *METAL complexes, *LITHIUM compounds, *PHENOL, *LIGANDS (Chemistry), *X-ray crystallography, *COMPLEX compounds
Abstract

A series of Li, Na, Mg, and Ca complexes with 2,6-di-tert-butyl-4-methylphenol (BHT) as the ligand has been synthesized,and their reactivity for the ring-opening polymerization of lactidehas been studied. The Ca complex with 2,2′-ethylidenebis(4,6-di-tert-butylphenol) (EDBP) as the ligand also has been synthesizedto compare with the BHT systems. All complexes, in the presence ofbenzyl alcohol as initiator, exhibit high activity for the ring-openingpolymerization of lactide. Polymerization activities follow the orderof Na ≫ Li > Ca ≫ Mg. Additionally, metal–BHTsystems are more efficient than metal–EDBP systems, and thissuperiority was pronounced in THF solution. Four model metal–BHTcomplexes with coordinated dimethoxyethane (DME) have been characterizedby single-crystal X-ray diffraction. These complexes exhibited a widevariation in the Cipso–O–metal angle (159.3°to 180.0°), and DFT calculations suggested that this flexibilityallows the metal to vary its electron density and thereby expeditethe catalytic cycle that requires both monomer activation and substratelability. [ABSTRACT FROM AUTHOR]

Published
2012
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