meso‐Tetrakis[4‐(diphenylphosphino)‐phenyl]porphyrin and a Water‐Soluble Octakis‐(phosphonium salt) Porphyrin Double‐Decker with a Cage Structure

A phosphino-substituted porphyrin was synthesized in its free and metalcontaining (M = 2H, Zn, Co) form for the first time (depicted on the right). The reaction of two porphyrin molecules of this type with α,ω-dihalogen compounds results in a water-soluble, macrocyclic phosphonium ion, in which the porphyrin rings are arranged parallel to each other, and together with the spacers this leads to a large cage. Whether guest molecules can be incorporated in this cavity requires further study.