α-Diimine-Palladium Complexes Incorporated in Vinylic-Addition Polynorbornenes: Synthesis and Catalytic Activity

alpha-Diimine polymeric ligands have been synthesized using the bicyclic norbornane structure, present in vinylic-addition polynorbornene (VA-PNB). The VA-PNB-diimine ligands have been prepared by functionalization of the copolymer obtained by Ni-catalyzed polymerization of norbornene and norbornenylcarbonate. Immobilized palladium complexes of the type VA-PNB-diimine-PdX2 have been prepared, and their catalytic activity has been tested. The trifluoroacetato complex (X = CF3COO) can be used as a recyclable precatalyst in the Suzuki reaction. It is the source of minute amounts of homogeneous palladium active species, which carry out the catalysis with high turnover numbers. The recovered polymeric complex can be reused several times with no significant loss of activity. The polymeric analogue to Brookhart's catalyst, VA-PNB-diimine-PdMeCl, can also polymerize ethylene, although it is less active than its monomeric counterparts.