Controlled cyclopolymerisation of 1,7-octadiyne derivatives using Grubbs catalyst

Abstract

Cyclopolymerisation of 1,6-heptadiyne derivatives by Grubbs catalysts gives the conjugated polymers containing a five-membered ring repeat unit. The first example of cyclopolymerisation of 1,7-octadiyne derivatives is demonstrated here to give a new class of conjugated polymer that contains six-memebered rings. This polymerisation was very challenging and efficient cyclopolymerisation was achieved only with monomers that showed a significant Thorpe–Ingold effect. By using a third-generation Grubbs catalyst, we obtained the polymers with excellent molecular weight control and narrow PDIs. This controlled polymerisation allowed the synthesis of diblock copolymers containing five- and six-membered rings, respectively, from 1,6-heptadiyne and the 1,7-octadiyne derivatives.