Ironporphyrins trapped sol–gel glasses: a chemometric approach

The optimised conditions for preparation of ironporphyrin (FeP)-template trapped silica obtained by the sol–gel process are analysed by fractional factorial design. The FeP iron 5,10,15,20-tetrakis(pentafluorophenyl)-porphyrin (FeTFPPCl), iron 5,10,15,20-tetrakis(2,6-dichlorophenyl-3-sulphonatophenyl)-porphyrin (FeTDCSPP(Na)4Cl), iron 5,10,15,20-tetrakis-p-carboxyphenylporphyrin (FeTCPP(Na)4Cl) and iron 5,10,15,20-tetrakis-p-methylpyridilporphyrin (FeTMPyP(Cl)5) were used. Pyridine or 4-phenylimidazole was used as template. Scanning electron microscopy (SEM) shows that the use of different porphyrins and conditions in the preparation of xerogel produce different product morphologies. The prepared materials have surface areas, between 300 and 1000 m2/g. The electron paramagnetic resonance spectra of trapped materials have characteristic signal of FeIII high spin, the presence of porphyrin species in a rhombic symmetry and porphyrin aggregates were also observed.