We present MNDO geometry optimization results and VEH band structure calculations on the base and protonated forms of polypyrrylenemethine (PPM), a conjugated polymer based on oxidized pyrrole rings bridged by a methine-type carbon. The 1.47 eV bandgap calculated for neutral PPM decreases to 0.78 eV after protonation of the nitrogens. This is a consequence of the geometry modifications imposed by the protonation process which leads to a situation where the pyrrole rings alternate between aromatic and quinoid geometries. It is important pointing out that both the neutral and protonated forms of PPM have been recently synthesized.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Materials Chemistry
- Polymers and Plastics