5,10,15,20-Tetra-p-phenylsulfonyporphinatocobalt(III), a water-soluble Co(III) porphyrin

An alternative procedure is described for producing diffraction-quality crystals of the sodium salt of the water-soluble porphyrin diaqua-5,10,15,20-tetra-p-phenylsulfonyporphinatocobalt(III), Na[Co(TPPS)(H2O)2]·4H2O by vapour diffusion of ethyl acetate into an aqueous solution of the porphyrin overlaid with a layer of acetone. The structure contains a large amount of disordered solvent in channels but application of an appropriate algorithm (SQUEEZE – an algorithm incorporated into PLATON that applies a Fourier transform of the observed density in the solvent areas and incorporates its contribution to the structure factors) permits a structure solution.