COVALENT BINDING OF REDOX-ACTIVE CENTERS TO PREFORMED REGIOREGULAR POLYTHIOPHENES

The synthesis of regioregular head-to-tail poly[3-(6-bromohexyl)thioph ene] is reported, together with its reaction with 2-carboxyanthraquino ne (Anth) to give an example of a regioregular polythiophene containin g pendant functional groups (87% loading). NMR data on the two soluble polymers are reported together with preliminary studies of some of th eir physical properties. Cyclic voltammetric studies of anthraquinone polymer coated electrodes show that the observed response is coverage dependent: thin films display four redox couples due to the Anth(0/-/2 -) processes and the p-and n-doping of the conjugated thiophene backbo ne. Thick films are rectifying in the sense that reduction of the Anth groups is inhibited on the negative sweep. Spectroelectrochemical stu dies confirm the nature of the anodic p-doping process (the film turns red to nearly colourless) and show characteristic changes on reductio n (red to black).