Half-Lanthanocene/Dialkylmagnesium-Mediated Coordinative Chain Transfer Copolymerization of Styrene and Hexene

The Cp*La(BH4)(2)(THF)(2)/n-butylethylmagnesium (BEM) catalytic system has been assessed for the coordinative chain transfer copolymerization of styrene and 1-hexene. Poly(styrene-co-hexene) statistical copolymers were obtained with number-average molecular weight up to 7600 g/mol, PDI around 1.4 and 1.5 and up to 23% hexene content. The occurence of chain transfer reactions in the presence of excess BEM is established in the course of the statistical copolymerization. Thanks to this transfer process, the quantity of 1-hexene in the copolymer is increased by a factor of about 3 for high ratio of hexene in the feed, extending the range of our concept of a chain transfer induced control of the composition of statistical copolymers to poly(styrene-co-hexene) copolymers. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 3778-3782, 2011