Cyclopolymerization of 1,6-heptadienes and 1,6,11-dodecatrienes having acyclic substituents catalyzed by Pd-diimine complexes

Abstract

Chloro(methyl)palladium complexes with 1,2-diimine ligand catalyze the cyclopolymerization of 1,6-heptadienes having two alkoxymethyl substituents at 4-position. The obtained polymers contain a trans-fused five-membered ring in every repeating unit. Molecular weights of the polymers are in the range of M n = 3,370–13,000 (M w/M n = 1.28–2.01, by GPC using polystyrene standard), depending on the monomer and the catalyst. The reaction using the Pd complex with a C 2 symmetrical structure forms the polymer with racemo linkage between the monomer units more than meso linkage. The polymerization under ethylene atmosphere produces the copolymer having the diene monomer unit composed of the five-membered ring and the branched oligoethylene block. 1,6,11-Dodecatrienes having four alkoxymethyl groups at the 4- and 9-positions undergo the cyclopolymerization to yield the polymer containing two five-membered rings in every monomer unit. Pd-diimine complexes polymerize 1,6-dienes having acyclic substituents and 1,6,11-dodecatrienes having four substituents at 4- and 9-positions to produce the new polymers having trans-five-membered rings along the polymer chain.