The structure/property relationship in a series of pyrrolic polysquaraines

Eight polymeric pyrrolic squaraines produced from bispyrroles separated by directly linked arene groups have been prepared and studied for their structure/property relationship. Of the eight only two electrically conduct, those containing furan and thiophene, respectively. These two polymers are unique in this series because they are the only ones that are possibly flat and closely π-stacked, as suggested by the presented crystal structure of the furan bispyrrole and also indicated in their powder XRD patterns. Electron microscope images of the particulate grains of each polymer were also utilized to explain the physical behaviour of the two electrically conductive polymers. Thermogravimetric analysis of each of the polymers shows that they are capable of absorbing up to almost twice their own weight in nitrogen.