Porphyrins are well-known organic pigments that have vital roles in natural systems. The high stability and ease of modification of porphyrins make them suitable for diverse applications, e.g., in materials science and catalysts. In spite of the maturity of porphyrin chemistry, no porphyrin derivatives fused with phospholes (the phosphorus analogue of pyrrole) have been reported.

Tomohiro Higashino, Hiroshi Imahori, and colleagues, Kyoto University, Japan, have synthesized a phosphole-fused porphyrin dimer. This molecule was prepared using bis(pyrrolo)phosphole as a key building block. The porphyrin dimer possesses a large π-conjugated system as well as an excellent electron-accepting ability, which are typical features of porphyrins and phospholes, respectively.

According to the researchers, further modifications on the porphyrin and/or phosphole moieties could realize interesting optical and electrochemical properties.

• Fusing Porphyrins and Phospholes: Synthesis and Analysis of a Phosphorus-Containing Porphyrin,
  Tomohiro Higashino, Tomoki Yamada, Tsuneaki Sakurai, Shu Seki, Hiroshi Imahori,
  Angew. Chem. Int. Ed. 2016.
  DOI: 10.1002/anie.201607417