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Bulletin of the Korean Chemical Society (BKCS)

ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 31, Number 4
BKCSDE 31(4)
April 20, 2010 

 
Title
Cobalt(III) Complexes of Various Salen-Type Ligand Bearing Four Quaternary
Ammonium Salts and Their Reactivity for CO2/Epoxide Copolymerization
Author
Bo Eun Kim, Jobi Kodiyan Varghese, Yonggyu Han, Bun Yeoul Lee*
Keywords
Carbon dioxide, Epoxide, Salen-cobalt complexes, Quaternary ammonium salt, Polymerization
Abstract
Ligand variation was carried out on a cobalt(III) complex of Salen-type ligand comprised of 1,2-cyclohexenediamine and salicylaldehyde bearing a methyl substituent on 3-position and -[CMe(CH2CH2CH2N+Bu3)2] on 5-position, which is a highly active catalyst for CO2/propylene oxide copolymerization. Replacement of the methyl substituent with bulky isopropyl group resulted in alteration of the binding mode, consequently lowering turnover frequency significantly. Replacement with an ethyl group preserved binding mode and activity. Replacement of the tributylammonium unit with trihexylammonium or trioctylammonium, or replacement of 1,2-cyclohexenediamino unit with -NC(Me)2CH2N- decreased activity, even though the binding mode was unaltered.
Page
829 - 834
Full Text
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