Studies of the end-capping of living anionic poly(ferrocenyldimethylsilane) with 1,1-diphenylethylene

The efficiency of capping poly(ferrocenyldimethylsilane) (PFDMS) with 1,1-diphenylethylene (DPE) at room temperature and at 50 °C is reported. The capping of living anionic PFDMS chains was investigated by synthesizing short PFDMS oligomers of 10 repeat monomer units for which the end groups can be probed by ¹H NMR. DPE is known to mediate the reactivity of the PFDMS, permitting the synthesis of block copolymers unobtainable by direct, sequential, living anionic polymerization such as poly(ferrocenyldimethylsilane)-block-poly(methylmethacrylate) (PFDMS-b-PMMA) and poly(ferrocenyldimethylsilane)-block-poly(2-vinylpyridine) (PFDMS-b-P2VP). However, at room temperature addition of the DPE is slow. We report that carrying out the capping of living PFDMS chains at elevated temperatures (50 °C) avoids the need to use a second reagent to facilitate the addition of DPE, or follow more complex synthetic routes.