Quantification of the Steric Influence of Alkylphosphine鈥揝ulfonate Ligands on Polymerization, Leading to High-Molecular-Weight Copolymers of Ethylene and Polar Monomers

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• 作者：Yusuke Ota ; Shingo Ito ; Jun-ichi Kuroda ; Yoshikuni Okumura ; Kyoko Nozaki
• 刊名：Journal of the American Chemical Society
• 出版年：2014
• 出版时间：August 27, 2014
• 年：2014
• 卷：136
• 期：34
• 页码：11898-11901
• 全文大小：270K
• ISSN：1520-5126

文摘

A series of palladium/alkylphosphine鈥搒ulfonate catalysts were synthesized and examined in the homopolymerization of ethylene and the copolymerization of ethylene and polar monomers. Catalysts with alkylphosphine鈥搒ulfonate ligands containing sterically demanding alkyl substituents afforded (co)polymers whose molecular weight was increased by up to 2 orders of magnitude relative to polymers obtained from previously reported catalyst systems. The polymer molecular weight was found to be closely correlated to the Sterimol B5 parameter of the alkyl substituents in the alkylphosphine鈥搒ulfonate ligands. Thus, the use of bulky alkylphosphine鈥搒ulfonate ligands represents an effective and versatile method to prepare high-molecular-weight copolymers of ethylene and various polar monomers, which are difficult to obtain by previously reported methods.