Delocalised electrons along the conjugated backbone of polypyrrole result in an extended pi-system which is filled with valence electrons. Adding or removing electrons from the pi-system (doping) produces a charged unit called a bipolaron unit which is cabable of conducting electricity.
Optical properties are also affected by electron delocalisation
as they respond to changes in applied potential, temperature,
solvent and binding to other molecules.
* Indicates that the button contains a hover feature. Click on the JSmol window and hover over part of the molecule to see its repeating unit.