Bidirectional ROMP of paracylophane-1,9-dienes to tri- and penta-block p-phenylenevinylene copolymers

Dialkoxy and dialkyl substituted paracyclophane-1,9-dienes undergo bidirectional ring opening metathesis polymerisation (ROMP) on addition of bifunctional Hoveyda-Grubbs initiators. The living nature of the polymerisation was demonstrated for different [monomer]/[initiator] ratios and block copolymers were prepared by sequential ROMP and ROMP-ATRP to give fully conjugated rod-rod-rod and partially conjugated coil-rod-coil ABA and BAB triblock copolymers, respectively. These strategies were successfully extended to the synthesis of the corresponding pentablock copolymers. Optical and electrochemical properties of cis/trans and all trans homo and block copolymers are discussed.