Synthesis and and characterisation of novel regioregular polythiophenes - Tuning the redox properties

The synthesis and full characterisation of three novel regioregular polythiophenes 8, 9, and 15 is presented. By varying the nature of the substituents on the polythiophene backbone in these materials it is possible to increase their first oxidation potential by almost 0.5 V. Because the first reduction potential follows the same trend, the electrochemical band gap of these polymers is essentially constant. The constant band gap inferred from the electrochemical data is confirmed by the onset of the optical absorption spectrum of the polythiophenes, which shows only small changes.