Effect of nonpolar field formed by polymer ligand on the oxidation of 2,6-xylenol catalyzed by Cu complexes

The oxidative polymerization catalyzed by Cu(II)-poly(vinylpyridine) derivatives and the effect of the nonpolar field formed by the polymer ligand on the catalysis was studied in dimethyl sulfoxide (DMSO) solvent. The catalytic activity of the Cu complex increases in the following order; Cu-(styrene-vinylpyridine copolymer) (St·VP) complex > Cu-partially quarternized (by benzyl chloride) poly(vinylpyridine)(BCQP) complex > Cu-poly(vinylpyridine) (PVP) complex > Cu-pyridine (Py) complex > Cu-partially quarternized (by ethyl bromide) poly(vinylpyridine) (EBQP) complex. This order is the same as that of the reoxidation rate constant of the catalyst. Acceleration of k_o process in Cu-St>VP and Cu-BCQP systems, where the active site is in the nonpolar field formed by the polymer ligand, is explained by an increase in strength of the coordination bonds.