Theoretical approach to the design of supramolecular conjugated porphyrin polymers

The design of novel conjugated polymers mainly consisting of porphyrin and/or phthalocyanine rings is studied by the use of the tight-binding crystal orbital method based on the extended Hückel approximation. This paper focuses on the tuning of the electronic structures of these polymers by ethynyl bridging as well as various linkage modes. It has been clarified that the bridging sites (meso-to-meso, meso-to-β and β-to-β) and the bridging patterns (linear or zigzag) in the ethynyl-bridged porphyrin polymers are crucial for tuning the π-conjugation throughout the main chain. Furthermore, comparison of two-dimensional (2D) porphyrin polymer sheets and stacked porphyrin polymers demonstrates quite different electronic properties.