Ironporphyrins trapped sol-gel glasses: a chemometric approach

The optimised conditions for preparation of ironporphyrin (FeP)-template tr apped silica obtained by the sol-gel process are analysed by fractional fac torial design. The FeP iron 5,10,15,20-tetrakis(pentafluorophenyl)-porphyri n (FeTFPPCl), iron 5,10,15,20-tetrakis(2,6-dichlorophenyl-3-sulphonatopheny l)-porphyrin (FeTDCSPP(Na)(4)Cl), iron 5,10,15,20-tetrakis-p-carboxyphenylp orphyrin (FeTCPP(Na)(4)Cl) and iron 5,10,15,20-tetrakis-p-methylpyridilporp hyrin (FeTMPyP(Cl)(5)] were used. Pyridine or 4-phenylimidazole was used as template. Scanning electron microscopy (SEM) shows that the use of differe nt porphyrins and conditions in the preparation of xerogel produce differen t product morphologies. The prepared materials have surface areas. between 300 and 1000 m(2)/g. The electron paramagnetic resonance spectra of trapped materials have characteristic signal of Fe-III high spin, the presence of porphyrin species in a rhombic symmetry and porphyrin aggregates were also observed. (C) 2001 Elsevier Science B.V. All rights reserved.