Copolymerization of 1,3-butadiene and norbornene catalyzed by Ni complexes [1]

Abstract (bpy)NiBr 2 catalyzes the copolymerization of butadiene and norbornene (56:44) in the presence of methylaluminoxane at 30 °C. 1 H NMR spectrum of the copolymer contains signals of norbornene units and 1,4-butadiene units and shows the molar ratio of the two monomer units to be 56:44. Copolymerization with a higher portion of norbornene monomer catalyzed by (bpy)NiBr 2 affords a solid copolymer rich in norbornene unit, whereas the copolymerization with a higher portion of butadiene forms an oily copolymer rich in butadiene unit. Composition of the monomer units of the copolymer in terms of butadiene/norbornene ratio varies from 12:88 to 91:9, depending on the initial ratio of the monomers; this finding is different from the previous results obtained using Ni catalyst.