5,10,15,20-Tetrakis(1-methylpyridinium-4-yl)porphyrin tetraiodide tetrahydrate

The asymmetric unit of the title compound, C44H38N82+·4I−·4H2O, comprises two halves of non-equivalent cations of 5,10,15,20-tetrakis(1-methylpyridinium)porphyrin (with the full molecule of each completed by the application of inversion symmetry), four charge balancing iodide anions and four water molecules of crystallization (two water molecules are fully occupied and four molecules have a site occupancy of 50%). The porphyrin cations are arranged into supramolecular columns parallel to the b axis, mediated by π–π [centroid–centroid distance = 3.762 (4) Å] and C—H...π supramolecular interactions [C...centroid distance = 3.522 (7) Å, C—H...centroid = 128°], leading to the formation of columns parallel to the b axis. The close packing leads to the presence of a one-dimensional channel filled with partially occupied water molecules engaged in O—H...O and O—H...I hydrogen bonds