Electrooxidative polymerization of three new p-nitrophenyl-functionalized t
hiophene derivatives leads to materials which show the electroactivities of
both nitrobenzene and polythiophene. However, other than the reversible re
dox transition in solution, the nitro groups exhibit a complex nature of th
e cyclic voltammetric curve in the obtained solid polymeric films. It was f
ound that the electrochemical behavior of the nitro groups has a dramatic e
ffect on the conjugated pi-electron systems of the substituted polythiophen
es. Upon electrochemical addressing of the nitro groups the electroactiviti
es of the corresponding polymers decrease rapidly compared to their analogo
us polymers without nitro groups. FTIR studies of these polymers revealed t
hat after the reduction/oxidation process of the nitro groups still a large
amount of electrolyte salt remains in the polymer films. As typical of fun
ctionalized polythiophenes, however, these new polymers can be switched und
er controlled conditions between their oxidized and neutral forms and exhib
it the typical properties of electroactive polythiophenes, e.g., electrochr
omism.