Fig. 1. Top row: chemical structures of the porphyrin, chlorin and phthalocyanine scaffolds. Bottom row: chemical structures of manganese texaphyrin (R₁ = –CH₂CH₂CH₂OH, R₂ = –(CH₂CH₂O)₃CH₃) and 26 π-electron-conjugated bis-metal (Zn and Cu) dioxohexaphyrin complexes (M = Cu or Zn, R₃ = C₆F₅) reported by Furuta and collaborators.²².