Stability of Fe(III) and Sn(IV) Metalloporphyrins Adsorbed on Cation-Exchanged Montmorillonite

The iron(III)tetraphenylporphyrin chloride Fe(III)TPPCl, iron(III)tetra-naphthylporphyrin Fe(III)TNPCl, μ-oxo-bis[tetraphenylporphyriniron(III)] [(Fe(III)TPP)2O], μ-oxo-bis[tetranaphthylporphyriniron(III)] [(Fe(III)TNP)2O], tin(IV)tetraphenylporphyrin chloride Sn(IV)TPPCl2 and tin(IV)tetra-naphthylporphyrin Sn(IV)TNPCl2 complexes were all found to be adsorbed onto the montmorillonite MMT clay without demetallation. The evidence from the visible absorption and diffuse reflectance spectra all showed that the species present on the montmorillonite are the metallated form. Also the evidence from Mossbauer spectroscopy confirm these findings. The only process that occurs is that the dimeric form of the iron complexes underwent transformation to the monomeric form. The clay-complex systems were characterized using visible absorption spectra, diffuse reflectance spectra, X-ray diffraction, Mossbauer spectra and Electron microscopy. HIGHLIGHTS Fe(III)TPPCl, Fe(III)TNPCl, Sn(IV)TPPCl2, and Sn(IV)TNPCl2 porphyrin complexes adsorbed onto the montmorillonite clay without demetallation The dimeric forms of iron porphyrin complexes [(Fe(III)TPP)2O] and [(Fe(III)TNP)2O are converted to the monomeric form when adsorbed on montmorillonite clay The weak acidity of montmorillonite clay does not have the ability to cause demetallation of the metallo complexes of porphyrin