Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA.
J Am Chem Soc. 2013 Feb 13;135(6):2132-5. doi: 10.1021/ja312463f. Epub 2013 Jan 29.
Modulation of steric interactions remote from the active sites within a series of dinuclear bis-propagators derived from racemic 2-4 was used to attenuate the rate of reversible chain transfer between active transition-metal centers and excess equivalents of inactive main-group-metal alkyl species relative to chain growth propagation, as a strategy for achieving the stereoselective living coordinative chain transfer polymerization of propene to provide isotactic stereoblock polypropene. Under identical conditions, the corresponding mononuclear propagator derived from racemic 1 produced only atactic polypropene.
通过调节一系列源于外消旋 2-4 的双核双引发剂中远离活性位的立体位阻，可削弱活性过渡金属中心与过量非活性主族金属烷基物种之间可逆链转移的速率，从而促进链增长，以此作为实现丙烯的立体选择性配位链转移聚合以得到等规立构嵌段聚丙烯的策略。在相同条件下，源于外消旋 1 的相应单核引发剂仅得到无规聚丙烯。
