Self-assembly to ordered films of the homoassociate solutions of the tetrasodium salt of 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin dihydrochloride

Films were obtained from the evaporation on flat glass substrates of homoassociate water solutions of the title porphyrin. The films of 1 were characterized by UV–VIS and FT-IR spectroscopy, microscopy, X-ray diffraction, thermogravimetry (TG) and differential scanning calorimetry (DSC). The films are composed by a birefrigent organic phase and NaCl crystallites; the organic phase shows an orientated structure. The water content of the film depends directly on the water-vapour pressure of the surrounding atmosphere; a change of structure occurs for pH2O>10 Torr and there is a transition to gel-like material for pH2O>20 Torr. In the organic phase, water, sodium, and chloride ions are placed in layers or channels parallel to the evaporation surface with thickness depending on the water content.