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.
|Original language||English (US)|
|Number of pages||4|
|State||Published - Jun 7 1991|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Materials Chemistry
- Polymers and Plastics