PREPARATION OF POLYMERS WITH VIOLOGEN MOIETIES AND THEIR APPLICATION TO THE SELECTIVE REDUCTION OF SUBSTITUTED NITROARENES

Polymers with viologen moieties were synthesized by using polychloreth yl vinyl ether (PCEVE) as mother supports. These polymers were used as electron-transfer catalysts (ETC) for the reduction of substituted ni troarenes under heterophase conditions (reductant: Na2S2O4 in CH2Cl2-H 2O). The experimental results show that the substituted nitroarenes we re reduced selectively and efficiently to the corresponding aniline de rivatives in the presence of viologen polymers. The catalytic active s pecies of viologen were detected by ESR and electrochemical methods. I t was found that the viologen cation radical (V-+>) acts as the active species during the viologen-mediated reduction of substituted nitroar enes.