Analogies and differences in palladium-catalyzed CO/styrene and ethylene/methyl acrylate copolymerization reactions

The catalytic CO/styrene and ethylene/methyl acrylate copolymerizations are compared for the first time by applying the same precatalysts. With this aim, Pd(II) neutral, [Pd(CH3)Cl(N-N)], and monocationic, [Pd(CH3)(L)(N-N)][PF6] (L = CH3CN, dmso), complexes with 1-naphthyl- and 2-naphthyl-substitued -diimines with both an acenaphthene (BIAN) and a diazabutadiene (DAB) skeleton have been studied. In the case of the complexes with the 1-naphthyl-substituted ligands syn and anti isomers are found both in solid state and in solution. All the monocationic complexes generate active catalysts for the CO/styrene copolymerization leading to syndiotactic or isotactic/atactic stereoblock copolymers depending on the ligand bonded to palladium. Instead, in the case of the ethylene/methyl acrylate copolymerization only the complexes with the 1-naphthyl-substituted ligands generate catalysts for this reaction.