Abstract:
Allene derivatives have cumulated double bonds and can be regarded as the isomers of propargyl derivatives. Due to their unique structures with 1,2-cumulative double bonds, they can exhibit special reactivity and can selectively conduct 1,2- or 2,3-position polymerization under appropriate conditions. Taking advantage of this characteristic, polymers with exomethylene substituents can be obtained through the selective polymerization of either part (1,2- or 2,3-)of the cumulated double bonds. Allylnickel( II)complexes and poly( 3-hexylthiophene)( P3HT)have been reported to promote the living/controlled polymerization of allene derivatives. The polymerization of allene using the catalysts such as allylnickel( II)complexes and poly( 3-hexylthiophene)( P3HT)is presented with detailed discussion, including the impact of the substituents on the monomers, the reaction solvent during the polymerization using allylnickel( II)complexes as catalyst, the application of living polymerization of allene using different allylnickel( II)complexes, and the self-assembly performance of polyallenes using P3HT as catalyst. In addition, living polymerizations of chiral allene monomers with allylnickel complex as a catalyst afforded helical polyallenes was also described. The helical structure of the polyallenes was quite stable with a preferred handedness in aprotic solvents. The helical polyalkenes behaved pH-responsive property due to the amino group on the pendant.