Living coordination polymerization of allene (1,2-propadiene) by pi-allylnickel catalyst and selective hydrosilylation reaction of polymers having polyallene units

The coordination polymerization of allene (1,2-propadiene, 2A) was carried out by [(eta (3)-allyl)NiOCOCF3](2) (1) to obtain narrowly dispersed poly(2 A) in high yield. The linear relationship between the ratio of 2A/1 and the molecular weight of the polymer supported the living character of the poly merization. The block copolymer of 2A with l-phenylethyl isonitrile (2B) wa s obtained in a two-stage process, the polymerization of 2A followed by tha t of 2B. Hydrosilylation of poly(2A) or poly(2A)-block-poly(2B) with silico n hydrides (3A and 3B) in the presence of H2PtCl6 catalyst successfully inc orporated the silyl groups into the polyallene segments.