The catalytic effects of the aminated polystyrene ligand in the oxidative polymerization of 2,6‐xylenol

Abstract 2,6‐Xylenol (2) was oxidatively polymerized using a copper complex of partially diethylaminomethylated polystyrene (1) as catalyst in a homogeneous o‐dichlorobenzene solution. The catalytic effects of the Cu‐1 complex are discussed on the basis of the kinetic parameters and spectroscopic measurements. The catalytic activity of the Cu‐1 complex was higher in the dimerization of 2, compared to the Cu‐triethylamine catalyst, but the Cu‐1 catalyzed polymerization of oligo(2) proceeded slower. The smaller value of K1 (the formation constant of the intermediate complex) and the lower molecular weight of the polymer obtained with the Cu‐1 catalyst system suggests that a bulky 1‐ligand obstructs the coordination of the substrate to the cupric ion. The higher catalytic activity of the Cu‐1 complex is caused by the fact that the rate constant of the electron‐transfer step (ke) is larger and the activation enthalpy is smaller. This is due to an acceleration of the electron transfer step by the strain in the chain of ligand 1.